src/libpq/include/nodes/parsenodes.h

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/*-------------------------------------------------------------------------
 *
 * parsenodes.h
 *        definitions for parse tree nodes
 *
 *
 * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.292.2.1 2005/11/22 18:23:28 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#ifndef PARSENODES_H
#define PARSENODES_H

#include "nodes/primnodes.h"


/* Possible sources of a Query */
typedef enum QuerySource
{
        QSRC_ORIGINAL,                          /* original parsetree (explicit query) */
        QSRC_PARSER,                            /* added by parse analysis */
        QSRC_INSTEAD_RULE,                      /* added by unconditional INSTEAD rule */
        QSRC_QUAL_INSTEAD_RULE,         /* added by conditional INSTEAD rule */
        QSRC_NON_INSTEAD_RULE           /* added by non-INSTEAD rule */
} QuerySource;

/*
 * Grantable rights are encoded so that we can OR them together in a bitmask.
 * The present representation of AclItem limits us to 16 distinct rights,
 * even though AclMode is defined as uint32.  See utils/acl.h.
 *
 * Caution: changing these codes breaks stored ACLs, hence forces initdb.
 */
typedef uint32 AclMode;                 /* a bitmask of privilege bits */

#define ACL_INSERT              (1<<0)  /* for relations */
#define ACL_SELECT              (1<<1)
#define ACL_UPDATE              (1<<2)
#define ACL_DELETE              (1<<3)
#define ACL_RULE                (1<<4)
#define ACL_REFERENCES  (1<<5)
#define ACL_TRIGGER             (1<<6)
#define ACL_EXECUTE             (1<<7)  /* for functions */
#define ACL_USAGE               (1<<8)  /* for languages and namespaces */
#define ACL_CREATE              (1<<9)  /* for namespaces and databases */
#define ACL_CREATE_TEMP (1<<10) /* for databases */
#define N_ACL_RIGHTS    11              /* 1 plus the last 1<<x */
#define ACL_NO_RIGHTS   0
/* Currently, SELECT ... FOR UPDATE/FOR SHARE requires UPDATE privileges */
#define ACL_SELECT_FOR_UPDATE   ACL_UPDATE


/*****************************************************************************
 *      Query Tree
 *****************************************************************************/

/*
 * Query -
 *        all statements are turned into a Query tree (via transformStmt)
 *        for further processing by the optimizer
 *
 *        utility statements (i.e. non-optimizable statements) have the
 *        utilityStmt field set, and the Query itself is mostly dummy.
 */
typedef struct Query
{
        NodeTag         type;

        CmdType         commandType;    /* select|insert|update|delete|utility */

        QuerySource querySource;        /* where did I come from? */

        bool            canSetTag;              /* do I set the command result tag? */

        Node       *utilityStmt;        /* non-null if this is a non-optimizable
                                                                 * statement */

        int                     resultRelation; /* target relation (index into rtable) */

        RangeVar   *into;                       /* target relation for SELECT INTO */
        bool            intoHasOids;    /* should target relation contain OIDs? */

        bool            hasAggs;                /* has aggregates in tlist or havingQual */
        bool            hasSubLinks;    /* has subquery SubLink */

        List       *rtable;                     /* list of range table entries */
        FromExpr   *jointree;           /* table join tree (FROM and WHERE clauses) */

        List       *rowMarks;           /* integer list of RT indexes of relations
                                                                 * that are selected FOR UPDATE/SHARE */

        bool            forUpdate;              /* true if rowMarks are FOR UPDATE, false if
                                                                 * they are FOR SHARE */
        bool            rowNoWait;              /* FOR UPDATE/SHARE NOWAIT option */

        List       *targetList;         /* target list (of TargetEntry) */

        List       *groupClause;        /* a list of GroupClause's */

        Node       *havingQual;         /* qualifications applied to groups */

        List       *distinctClause; /* a list of SortClause's */

        List       *sortClause;         /* a list of SortClause's */

        Node       *limitOffset;        /* # of result tuples to skip */
        Node       *limitCount;         /* # of result tuples to return */

        Node       *setOperations;      /* set-operation tree if this is top level of
                                                                 * a UNION/INTERSECT/EXCEPT query */

        /*
         * If the resultRelation turns out to be the parent of an inheritance
         * tree, the planner will add all the child tables to the rtable and store
         * a list of the rtindexes of all the result relations here. This is done
         * at plan time, not parse time, since we don't want to commit to the
         * exact set of child tables at parse time.  This field ought to go in
         * some sort of TopPlan plan node, not in the Query.
         */
        List       *resultRelations;    /* integer list of RT indexes, or NIL */
} Query;


/****************************************************************************
 *      Supporting data structures for Parse Trees
 *
 *      Most of these node types appear in raw parsetrees output by the grammar,
 *      and get transformed to something else by the analyzer.  A few of them
 *      are used as-is in transformed querytrees.
 ****************************************************************************/

/*
 * TypeName - specifies a type in definitions
 *
 * For TypeName structures generated internally, it is often easier to
 * specify the type by OID than by name.  If "names" is NIL then the
 * actual type OID is given by typeid, otherwise typeid is unused.
 *
 * If pct_type is TRUE, then names is actually a field name and we look up
 * the type of that field.      Otherwise (the normal case), names is a type
 * name possibly qualified with schema and database name.
 */
typedef struct TypeName
{
        NodeTag         type;
        List       *names;                      /* qualified name (list of Value strings) */
        Oid                     typeid;                 /* type identified by OID */
        bool            timezone;               /* timezone specified? */
        bool            setof;                  /* is a set? */
        bool            pct_type;               /* %TYPE specified? */
        int32           typmod;                 /* type modifier */
        List       *arrayBounds;        /* array bounds */
} TypeName;

/*
 * ColumnRef - specifies a reference to a column, or possibly a whole tuple
 *
 *              The "fields" list must be nonempty; its last component may be "*"
 *              instead of a regular field name.
 *
 * Note: any array subscripting or selection of fields from composite columns
 * is represented by an A_Indirection node above the ColumnRef.  However,
 * for simplicity in the normal case, initial field selection from a table
 * name is represented within ColumnRef and not by adding A_Indirection.
 */
typedef struct ColumnRef
{
        NodeTag         type;
        List       *fields;                     /* field names (list of Value strings) */
} ColumnRef;

/*
 * ParamRef - specifies a $n parameter reference
 */
typedef struct ParamRef
{
        NodeTag         type;
        int                     number;                 /* the number of the parameter */
} ParamRef;

/*
 * A_Expr - infix, prefix, and postfix expressions
 */
typedef enum A_Expr_Kind
{
        AEXPR_OP,                                       /* normal operator */
        AEXPR_AND,                                      /* booleans - name field is unused */
        AEXPR_OR,
        AEXPR_NOT,
        AEXPR_OP_ANY,                           /* scalar op ANY (array) */
        AEXPR_OP_ALL,                           /* scalar op ALL (array) */
        AEXPR_DISTINCT,                         /* IS DISTINCT FROM - name must be "=" */
        AEXPR_NULLIF,                           /* NULLIF - name must be "=" */
        AEXPR_OF                                        /* IS (not) OF - name must be "=" or "!=" */
} A_Expr_Kind;

typedef struct A_Expr
{
        NodeTag         type;
        A_Expr_Kind kind;                       /* see above */
        List       *name;                       /* possibly-qualified name of operator */
        Node       *lexpr;                      /* left argument, or NULL if none */
        Node       *rexpr;                      /* right argument, or NULL if none */
} A_Expr;

/*
 * A_Const - a constant expression
 */
typedef struct A_Const
{
        NodeTag         type;
        Value           val;                    /* the value (with the tag) */
        TypeName   *typename;           /* typecast */
} A_Const;

/*
 * TypeCast - a CAST expression
 *
 * NOTE: for mostly historical reasons, A_Const parsenodes contain
 * room for a TypeName; we only generate a separate TypeCast node if the
 * argument to be casted is not a constant.  In theory either representation
 * would work, but it is convenient to have the target type immediately
 * available while resolving a constant's datatype.
 */
typedef struct TypeCast
{
        NodeTag         type;
        Node       *arg;                        /* the expression being casted */
        TypeName   *typename;           /* the target type */
} TypeCast;

/*
 * FuncCall - a function or aggregate invocation
 *
 * agg_star indicates we saw a 'foo(*)' construct, while agg_distinct
 * indicates we saw 'foo(DISTINCT ...)'.  In either case, the construct
 * *must* be an aggregate call.  Otherwise, it might be either an
 * aggregate or some other kind of function.
 */
typedef struct FuncCall
{
        NodeTag         type;
        List       *funcname;           /* qualified name of function */
        List       *args;                       /* the arguments (list of exprs) */
        bool            agg_star;               /* argument was really '*' */
        bool            agg_distinct;   /* arguments were labeled DISTINCT */
} FuncCall;

/*
 * A_Indices - array reference or bounds ([lidx:uidx] or [uidx])
 */
typedef struct A_Indices
{
        NodeTag         type;
        Node       *lidx;                       /* could be NULL */
        Node       *uidx;
} A_Indices;

/*
 * A_Indirection - select a field and/or array element from an expression
 *
 * The indirection list can contain both A_Indices nodes (representing
 * subscripting) and string Value nodes (representing field selection
 * --- the string value is the name of the field to select).  For example,
 * a complex selection operation like
 *                              (foo).field1[42][7].field2
 * would be represented with a single A_Indirection node having a 4-element
 * indirection list.
 *
 * Note: as of Postgres 8.0, we don't support arrays of composite values,
 * so cases in which a field select follows a subscript aren't actually
 * semantically legal.  However the parser is prepared to handle such.
 */
typedef struct A_Indirection
{
        NodeTag         type;
        Node       *arg;                        /* the thing being selected from */
        List       *indirection;        /* subscripts and/or field names */
} A_Indirection;

/*
 * ResTarget -
 *        result target (used in target list of pre-transformed parse trees)
 *
 * In a SELECT or INSERT target list, 'name' is the column label from an
 * 'AS ColumnLabel' clause, or NULL if there was none, and 'val' is the
 * value expression itself.  The 'indirection' field is not used.
 *
 * INSERT has a second ResTarget list which is the target-column-names list.
 * Here, 'val' is not used, 'name' is the name of the destination column,
 * and 'indirection' stores any subscripts attached to the destination.
 *
 * In an UPDATE target list, 'name' is the name of the destination column,
 * 'indirection' stores any subscripts attached to the destination, and
 * 'val' is the expression to assign.
 *
 * See A_Indirection for more info about what can appear in 'indirection'.
 */
typedef struct ResTarget
{
        NodeTag         type;
        char       *name;                       /* column name or NULL */
        List       *indirection;        /* subscripts and field names, or NIL */
        Node       *val;                        /* the value expression to compute or assign */
} ResTarget;

/*
 * SortBy - for ORDER BY clause
 */
#define SORTBY_ASC              1
#define SORTBY_DESC             2
#define SORTBY_USING    3

typedef struct SortBy
{
        NodeTag         type;
        int                     sortby_kind;    /* see codes above */
        List       *useOp;                      /* name of op to use, if SORTBY_USING */
        Node       *node;                       /* expression to sort on */
} SortBy;

/*
 * RangeSubselect - subquery appearing in a FROM clause
 */
typedef struct RangeSubselect
{
        NodeTag         type;
        Node       *subquery;           /* the untransformed sub-select clause */
        Alias      *alias;                      /* table alias & optional column aliases */
} RangeSubselect;

/*
 * RangeFunction - function call appearing in a FROM clause
 */
typedef struct RangeFunction
{
        NodeTag         type;
        Node       *funccallnode;       /* untransformed function call tree */
        Alias      *alias;                      /* table alias & optional column aliases */
        List       *coldeflist;         /* list of ColumnDef nodes for runtime
                                                                 * assignment of RECORD TupleDesc */
} RangeFunction;

/*
 * ColumnDef - column definition (used in various creates)
 *
 * If the column has a default value, we may have the value expression
 * in either "raw" form (an untransformed parse tree) or "cooked" form
 * (the nodeToString representation of an executable expression tree),
 * depending on how this ColumnDef node was created (by parsing, or by
 * inheritance from an existing relation).      We should never have both
 * in the same node!
 *
 * The constraints list may contain a CONSTR_DEFAULT item in a raw
 * parsetree produced by gram.y, but transformCreateStmt will remove
 * the item and set raw_default instead.  CONSTR_DEFAULT items
 * should not appear in any subsequent processing.
 *
 * The "support" field, if not null, denotes a supporting relation that
 * should be linked by an internal dependency to the column.  Currently
 * this is only used to link a SERIAL column's sequence to the column.
 */
typedef struct ColumnDef
{
        NodeTag         type;
        char       *colname;            /* name of column */
        TypeName   *typename;           /* type of column */
        int                     inhcount;               /* number of times column is inherited */
        bool            is_local;               /* column has local (non-inherited) def'n */
        bool            is_not_null;    /* NOT NULL constraint specified? */
        Node       *raw_default;        /* default value (untransformed parse tree) */
        char       *cooked_default; /* nodeToString representation */
        List       *constraints;        /* other constraints on column */
        RangeVar   *support;            /* supporting relation, if any */
} ColumnDef;

/*
 * inhRelation - Relations a CREATE TABLE is to inherit attributes of
 */
typedef struct InhRelation
{
        NodeTag         type;
        RangeVar   *relation;
        bool            including_defaults;
} InhRelation;

/*
 * IndexElem - index parameters (used in CREATE INDEX)
 *
 * For a plain index attribute, 'name' is the name of the table column to
 * index, and 'expr' is NULL.  For an index expression, 'name' is NULL and
 * 'expr' is the expression tree.
 */
typedef struct IndexElem
{
        NodeTag         type;
        char       *name;                       /* name of attribute to index, or NULL */
        Node       *expr;                       /* expression to index, or NULL */
        List       *opclass;            /* name of desired opclass; NIL = default */
} IndexElem;

/*
 * DefElem -
 *        a definition (used in definition lists in the form of defname = arg)
 */
typedef struct DefElem
{
        NodeTag         type;
        char       *defname;
        Node       *arg;                        /* a (Value *) or a (TypeName *) */
} DefElem;

/*
 * LockingClause - raw representation of FOR UPDATE/SHARE options
 *
 * Note: lockedRels == NIL means "all relations in query".      Otherwise it
 * is a list of String nodes giving relation eref names.
 */
typedef struct LockingClause
{
        NodeTag         type;
        List       *lockedRels;         /* FOR UPDATE or FOR SHARE relations */
        bool            forUpdate;              /* true = FOR UPDATE, false = FOR SHARE */
        bool            nowait;                 /* NOWAIT option */
} LockingClause;


/****************************************************************************
 *      Nodes for a Query tree
 ****************************************************************************/

/*--------------------
 * RangeTblEntry -
 *        A range table is a List of RangeTblEntry nodes.
 *
 *        A range table entry may represent a plain relation, a sub-select in
 *        FROM, or the result of a JOIN clause.  (Only explicit JOIN syntax
 *        produces an RTE, not the implicit join resulting from multiple FROM
 *        items.  This is because we only need the RTE to deal with SQL features
 *        like outer joins and join-output-column aliasing.)  Other special
 *        RTE types also exist, as indicated by RTEKind.
 *
 *        alias is an Alias node representing the AS alias-clause attached to the
 *        FROM expression, or NULL if no clause.
 *
 *        eref is the table reference name and column reference names (either
 *        real or aliases).  Note that system columns (OID etc) are not included
 *        in the column list.
 *        eref->aliasname is required to be present, and should generally be used
 *        to identify the RTE for error messages etc.
 *
 *        In RELATION RTEs, the colnames in both alias and eref are indexed by
 *        physical attribute number; this means there must be colname entries for
 *        dropped columns.      When building an RTE we insert empty strings ("") for
 *        dropped columns.      Note however that a stored rule may have nonempty
 *        colnames for columns dropped since the rule was created (and for that
 *        matter the colnames might be out of date due to column renamings).
 *        The same comments apply to FUNCTION RTEs when the function's return type
 *        is a named composite type.
 *
 *        In JOIN RTEs, the colnames in both alias and eref are one-to-one with
 *        joinaliasvars entries.  A JOIN RTE will omit columns of its inputs when
 *        those columns are known to be dropped at parse time.  Again, however,
 *        a stored rule might contain entries for columns dropped since the rule
 *        was created.  (This is only possible for columns not actually referenced
 *        in the rule.)  When loading a stored rule, we replace the joinaliasvars
 *        items for any such columns with NULL Consts.  (We can't simply delete
 *        them from the joinaliasvars list, because that would affect the attnums
 *        of Vars referencing the rest of the list.)
 *
 *        inh is TRUE for relation references that should be expanded to include
 *        inheritance children, if the rel has any.  This *must* be FALSE for
 *        RTEs other than RTE_RELATION entries.
 *
 *        inFromCl marks those range variables that are listed in the FROM clause.
 *        It's false for RTEs that are added to a query behind the scenes, such
 *        as the NEW and OLD variables for a rule, or the subqueries of a UNION.
 *        This flag is not used anymore during parsing, since the parser now uses
 *        a separate "namespace" data structure to control visibility, but it is
 *        needed by ruleutils.c to determine whether RTEs should be shown in
 *        decompiled queries.
 *
 *        requiredPerms and checkAsUser specify run-time access permissions
 *        checks to be performed at query startup.      The user must have *all*
 *        of the permissions that are OR'd together in requiredPerms (zero
 *        indicates no permissions checking).  If checkAsUser is not zero,
 *        then do the permissions checks using the access rights of that user,
 *        not the current effective user ID.  (This allows rules to act as
 *        setuid gateways.)
 *--------------------
 */
typedef enum RTEKind
{
        RTE_RELATION,                           /* ordinary relation reference */
        RTE_SUBQUERY,                           /* subquery in FROM */
        RTE_JOIN,                                       /* join */
        RTE_SPECIAL,                            /* special rule relation (NEW or OLD) */
        RTE_FUNCTION                            /* function in FROM */
} RTEKind;

typedef struct RangeTblEntry
{
        NodeTag         type;

        RTEKind         rtekind;                /* see above */

        /*
         * XXX the fields applicable to only some rte kinds should be merged into
         * a union.  I didn't do this yet because the diffs would impact a lot of
         * code that is being actively worked on.  FIXME later.
         */

        /*
         * Fields valid for a plain relation RTE (else zero):
         */
        Oid                     relid;                  /* OID of the relation */

        /*
         * Fields valid for a subquery RTE (else NULL):
         */
        Query      *subquery;           /* the sub-query */

        /*
         * Fields valid for a function RTE (else NULL):
         */
        Node       *funcexpr;           /* expression tree for func call */
        List       *coldeflist;         /* list of ColumnDef nodes for runtime
                                                                 * assignment of RECORD TupleDesc */

        /*
         * Fields valid for a join RTE (else NULL/zero):
         *
         * joinaliasvars is a list of Vars or COALESCE expressions corresponding
         * to the columns of the join result.  An alias Var referencing column K
         * of the join result can be replaced by the K'th element of joinaliasvars
         * --- but to simplify the task of reverse-listing aliases correctly, we
         * do not do that until planning time.  In a Query loaded from a stored
         * rule, it is also possible for joinaliasvars items to be NULL Consts,
         * denoting columns dropped since the rule was made.
         */
        JoinType        jointype;               /* type of join */
        List       *joinaliasvars;      /* list of alias-var expansions */

        /*
         * Fields valid in all RTEs:
         */
        Alias      *alias;                      /* user-written alias clause, if any */
        Alias      *eref;                       /* expanded reference names */
        bool            inh;                    /* inheritance requested? */
        bool            inFromCl;               /* present in FROM clause? */
        AclMode         requiredPerms;  /* bitmask of required access permissions */
        Oid                     checkAsUser;    /* if valid, check access as this role */
} RangeTblEntry;

/*
 * SortClause -
 *         representation of ORDER BY clauses
 *
 * tleSortGroupRef must match ressortgroupref of exactly one entry of the
 * associated targetlist; that is the expression to be sorted (or grouped) by.
 * sortop is the OID of the ordering operator.
 *
 * SortClauses are also used to identify targets that we will do a "Unique"
 * filter step on (for SELECT DISTINCT and SELECT DISTINCT ON).  The
 * distinctClause list is simply a copy of the relevant members of the
 * sortClause list.  Note that distinctClause can be a subset of sortClause,
 * but cannot have members not present in sortClause; and the members that
 * do appear must be in the same order as in sortClause.
 */
typedef struct SortClause
{
        NodeTag         type;
        Index           tleSortGroupRef;        /* reference into targetlist */
        Oid                     sortop;                 /* the sort operator to use */
} SortClause;

/*
 * GroupClause -
 *         representation of GROUP BY clauses
 *
 * GroupClause is exactly like SortClause except for the nodetag value
 * (it's probably not even really necessary to have two different
 * nodetags...).  We have routines that operate interchangeably on both.
 */
typedef SortClause GroupClause;


/*****************************************************************************
 *              Optimizable Statements
 *****************************************************************************/

/* ----------------------
 *              Insert Statement
 * ----------------------
 */
typedef struct InsertStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* relation to insert into */
        List       *cols;                       /* optional: names of the target columns */

        /*
         * An INSERT statement has *either* VALUES or SELECT, never both. If
         * VALUES, a targetList is supplied (empty for DEFAULT VALUES). If SELECT,
         * a complete SelectStmt (or set-operation tree) is supplied.
         */
        List       *targetList;         /* the target list (of ResTarget) */
        Node       *selectStmt;         /* the source SELECT */
} InsertStmt;

/* ----------------------
 *              Delete Statement
 * ----------------------
 */
typedef struct DeleteStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* relation to delete from */
        Node       *whereClause;        /* qualifications */
        List       *usingClause;        /* optional using clause for more tables */
} DeleteStmt;

/* ----------------------
 *              Update Statement
 * ----------------------
 */
typedef struct UpdateStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* relation to update */
        List       *targetList;         /* the target list (of ResTarget) */
        Node       *whereClause;        /* qualifications */
        List       *fromClause;         /* optional from clause for more tables */
} UpdateStmt;

/* ----------------------
 *              Select Statement
 *
 * A "simple" SELECT is represented in the output of gram.y by a single
 * SelectStmt node.  A SELECT construct containing set operators (UNION,
 * INTERSECT, EXCEPT) is represented by a tree of SelectStmt nodes, in
 * which the leaf nodes are component SELECTs and the internal nodes
 * represent UNION, INTERSECT, or EXCEPT operators.  Using the same node
 * type for both leaf and internal nodes allows gram.y to stick ORDER BY,
 * LIMIT, etc, clause values into a SELECT statement without worrying
 * whether it is a simple or compound SELECT.
 * ----------------------
 */
typedef enum SetOperation
{
        SETOP_NONE = 0,
        SETOP_UNION,
        SETOP_INTERSECT,
        SETOP_EXCEPT
} SetOperation;

typedef enum ContainsOids
{
        MUST_HAVE_OIDS,                         /* WITH OIDS explicitely specified */
        MUST_NOT_HAVE_OIDS,                     /* WITHOUT OIDS explicitely specified */
        DEFAULT_OIDS                            /* neither specified; use the default, which
                                                                 * is the value of the default_with_oids GUC
                                                                 * var */
} ContainsOids;

typedef struct SelectStmt
{
        NodeTag         type;

        /*
         * These fields are used only in "leaf" SelectStmts.
         *
         * into, intoColNames and intoHasOids are a kluge; they belong somewhere
         * else...
         */
        List       *distinctClause; /* NULL, list of DISTINCT ON exprs, or
                                                                 * lcons(NIL,NIL) for all (SELECT DISTINCT) */
        RangeVar   *into;                       /* target table (for select into table) */
        List       *intoColNames;       /* column names for into table */
        ContainsOids intoHasOids;       /* should target table have OIDs? */
        List       *targetList;         /* the target list (of ResTarget) */
        List       *fromClause;         /* the FROM clause */
        Node       *whereClause;        /* WHERE qualification */
        List       *groupClause;        /* GROUP BY clauses */
        Node       *havingClause;       /* HAVING conditional-expression */

        /*
         * These fields are used in both "leaf" SelectStmts and upper-level
         * SelectStmts.
         */
        List       *sortClause;         /* sort clause (a list of SortBy's) */
        Node       *limitOffset;        /* # of result tuples to skip */
        Node       *limitCount;         /* # of result tuples to return */
        LockingClause *lockingClause;           /* FOR UPDATE/FOR SHARE */

        /*
         * These fields are used only in upper-level SelectStmts.
         */
        SetOperation op;                        /* type of set op */
        bool            all;                    /* ALL specified? */
        struct SelectStmt *larg;        /* left child */
        struct SelectStmt *rarg;        /* right child */
        /* Eventually add fields for CORRESPONDING spec here */
} SelectStmt;


/* ----------------------
 *              Set Operation node for post-analysis query trees
 *
 * After parse analysis, a SELECT with set operations is represented by a
 * top-level Query node containing the leaf SELECTs as subqueries in its
 * range table.  Its setOperations field shows the tree of set operations,
 * with leaf SelectStmt nodes replaced by RangeTblRef nodes, and internal
 * nodes replaced by SetOperationStmt nodes.
 * ----------------------
 */
typedef struct SetOperationStmt
{
        NodeTag         type;
        SetOperation op;                        /* type of set op */
        bool            all;                    /* ALL specified? */
        Node       *larg;                       /* left child */
        Node       *rarg;                       /* right child */
        /* Eventually add fields for CORRESPONDING spec here */

        /* Fields derived during parse analysis: */
        List       *colTypes;           /* list of OIDs of output column types */
} SetOperationStmt;


/*****************************************************************************
 *              Other Statements (no optimizations required)
 *
 *              Some of them require a little bit of transformation (which is also
 *              done by transformStmt). The whole structure is then passed on to
 *              ProcessUtility (by-passing the optimization step) as the utilityStmt
 *              field in Query.
 *****************************************************************************/

/*
 * When a command can act on several kinds of objects with only one
 * parse structure required, use these constants to designate the
 * object type.
 */

typedef enum ObjectType
{
        OBJECT_AGGREGATE,
        OBJECT_CAST,
        OBJECT_COLUMN,
        OBJECT_CONSTRAINT,
        OBJECT_CONVERSION,
        OBJECT_DATABASE,
        OBJECT_DOMAIN,
        OBJECT_FUNCTION,
        OBJECT_INDEX,
        OBJECT_LANGUAGE,
        OBJECT_LARGEOBJECT,
        OBJECT_OPCLASS,
        OBJECT_OPERATOR,
        OBJECT_ROLE,
        OBJECT_RULE,
        OBJECT_SCHEMA,
        OBJECT_SEQUENCE,
        OBJECT_TABLE,
        OBJECT_TABLESPACE,
        OBJECT_TRIGGER,
        OBJECT_TYPE,
        OBJECT_VIEW
} ObjectType;

/* ----------------------
 *              Create Schema Statement
 *
 * NOTE: the schemaElts list contains raw parsetrees for component statements
 * of the schema, such as CREATE TABLE, GRANT, etc.  These are analyzed and
 * executed after the schema itself is created.
 * ----------------------
 */
typedef struct CreateSchemaStmt
{
        NodeTag         type;
        char       *schemaname;         /* the name of the schema to create */
        char       *authid;                     /* the owner of the created schema */
        List       *schemaElts;         /* schema components (list of parsenodes) */
} CreateSchemaStmt;

typedef enum DropBehavior
{
        DROP_RESTRICT,                          /* drop fails if any dependent objects */
        DROP_CASCADE                            /* remove dependent objects too */
} DropBehavior;

/* ----------------------
 *      Alter Table
 * ----------------------
 */
typedef struct AlterTableStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* table to work on */
        List       *cmds;                       /* list of subcommands */
        ObjectType      relkind;                /* type of object */
} AlterTableStmt;

typedef enum AlterTableType
{
        AT_AddColumn,                           /* add column */
        AT_ColumnDefault,                       /* alter column default */
        AT_DropNotNull,                         /* alter column drop not null */
        AT_SetNotNull,                          /* alter column set not null */
        AT_SetStatistics,                       /* alter column statistics */
        AT_SetStorage,                          /* alter column storage */
        AT_DropColumn,                          /* drop column */
        AT_DropColumnRecurse,           /* internal to commands/tablecmds.c */
        AT_AddIndex,                            /* add index */
        AT_ReAddIndex,                          /* internal to commands/tablecmds.c */
        AT_AddConstraint,                       /* add constraint */
        AT_ProcessedConstraint,         /* pre-processed add constraint (local in
                                                                 * parser/analyze.c) */
        AT_DropConstraint,                      /* drop constraint */
        AT_DropConstraintQuietly,       /* drop constraint, no error/warning (local in
                                                                 * commands/tablecmds.c) */
        AT_AlterColumnType,                     /* alter column type */
        AT_ToastTable,                          /* create toast table */
        AT_ChangeOwner,                         /* change owner */
        AT_ClusterOn,                           /* CLUSTER ON */
        AT_DropCluster,                         /* SET WITHOUT CLUSTER */
        AT_DropOids,                            /* SET WITHOUT OIDS */
        AT_SetTableSpace,                       /* SET TABLESPACE */
        AT_EnableTrig,                          /* ENABLE TRIGGER name */
        AT_DisableTrig,                         /* DISABLE TRIGGER name */
        AT_EnableTrigAll,                       /* ENABLE TRIGGER ALL */
        AT_DisableTrigAll,                      /* DISABLE TRIGGER ALL */
        AT_EnableTrigUser,                      /* ENABLE TRIGGER USER */
        AT_DisableTrigUser                      /* DISABLE TRIGGER USER */
} AlterTableType;

typedef struct AlterTableCmd    /* one subcommand of an ALTER TABLE */
{
        NodeTag         type;
        AlterTableType subtype;         /* Type of table alteration to apply */
        char       *name;                       /* column, constraint, or trigger to act on,
                                                                 * or new owner or tablespace */
        Node       *def;                        /* definition of new column, column type,
                                                                 * index, or constraint */
        Node       *transform;          /* transformation expr for ALTER TYPE */
        DropBehavior behavior;          /* RESTRICT or CASCADE for DROP cases */
} AlterTableCmd;


/* ----------------------
 *      Alter Domain
 *
 * The fields are used in different ways by the different variants of
 * this command.
 * ----------------------
 */
typedef struct AlterDomainStmt
{
        NodeTag         type;
        char            subtype;                /*------------
                                                                 *      T = alter column default
                                                                 *      N = alter column drop not null
                                                                 *      O = alter column set not null
                                                                 *      C = add constraint
                                                                 *      X = drop constraint
                                                                 *------------
                                                                 */
        List       *typename;           /* domain to work on */
        char       *name;                       /* column or constraint name to act on */
        Node       *def;                        /* definition of default or constraint */
        DropBehavior behavior;          /* RESTRICT or CASCADE for DROP cases */
} AlterDomainStmt;


/* ----------------------
 *              Grant|Revoke Statement
 * ----------------------
 */
typedef enum GrantObjectType
{
        ACL_OBJECT_RELATION,            /* table, view, sequence */
        ACL_OBJECT_DATABASE,            /* database */
        ACL_OBJECT_FUNCTION,            /* function */
        ACL_OBJECT_LANGUAGE,            /* procedural language */
        ACL_OBJECT_NAMESPACE,           /* namespace */
        ACL_OBJECT_TABLESPACE           /* tablespace */
} GrantObjectType;

typedef struct GrantStmt
{
        NodeTag         type;
        bool            is_grant;               /* true = GRANT, false = REVOKE */
        GrantObjectType objtype;        /* kind of object being operated on */
        List       *objects;            /* list of RangeVar nodes, FuncWithArgs nodes,
                                                                 * or plain names (as Value strings) */
        List       *privileges;         /* list of privilege names (as Strings) */
        /* privileges == NIL denotes "all privileges" */
        List       *grantees;           /* list of PrivGrantee nodes */
        bool            grant_option;   /* grant or revoke grant option */
        DropBehavior behavior;          /* drop behavior (for REVOKE) */
} GrantStmt;

typedef struct PrivGrantee
{
        NodeTag         type;
        char       *rolname;            /* if NULL then PUBLIC */
} PrivGrantee;

/*
 * Note: FuncWithArgs carries only the types of the input parameters of the
 * function.  So it is sufficient to identify an existing function, but it
 * is not enough info to define a function nor to call it.
 */
typedef struct FuncWithArgs
{
        NodeTag         type;
        List       *funcname;           /* qualified name of function */
        List       *funcargs;           /* list of Typename nodes */
} FuncWithArgs;

/* This is only used internally in gram.y. */
typedef struct PrivTarget
{
        NodeTag         type;
        GrantObjectType objtype;
        List       *objs;
} PrivTarget;

/* ----------------------
 *              Grant/Revoke Role Statement
 *
 * Note: the lists of roles are lists of names, as Value strings
 * ----------------------
 */
typedef struct GrantRoleStmt
{
        NodeTag         type;
        List       *granted_roles;      /* list of roles to be granted/revoked */
        List       *grantee_roles;      /* list of member roles to add/delete */
        bool            is_grant;               /* true = GRANT, false = REVOKE */
        bool            admin_opt;              /* with admin option */
        char       *grantor;            /* set grantor to other than current role */
        DropBehavior behavior;          /* drop behavior (for REVOKE) */
} GrantRoleStmt;

/* ----------------------
 *              Copy Statement
 * ----------------------
 */
typedef struct CopyStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* the relation to copy */
        List       *attlist;            /* List of column names (as Strings), or NIL
                                                                 * for all columns */
        bool            is_from;                /* TO or FROM */
        char       *filename;           /* if NULL, use stdin/stdout */
        List       *options;            /* List of DefElem nodes */
} CopyStmt;

/* ----------------------
 *              Create Table Statement
 *
 * NOTE: in the raw gram.y output, ColumnDef, Constraint, and FkConstraint
 * nodes are intermixed in tableElts, and constraints is NIL.  After parse
 * analysis, tableElts contains just ColumnDefs, and constraints contains
 * just Constraint nodes (in fact, only CONSTR_CHECK nodes, in the present
 * implementation).
 * ----------------------
 */

/* What to do at commit time for temporary relations */
typedef enum OnCommitAction
{
        ONCOMMIT_NOOP,                          /* No ON COMMIT clause (do nothing) */
        ONCOMMIT_PRESERVE_ROWS,         /* ON COMMIT PRESERVE ROWS (do nothing) */
        ONCOMMIT_DELETE_ROWS,           /* ON COMMIT DELETE ROWS */
        ONCOMMIT_DROP                           /* ON COMMIT DROP */
} OnCommitAction;

typedef struct CreateStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* relation to create */
        List       *tableElts;          /* column definitions (list of ColumnDef) */
        List       *inhRelations;       /* relations to inherit from (list of
                                                                 * inhRelation) */
        List       *constraints;        /* constraints (list of Constraint nodes) */
        ContainsOids hasoids;           /* should it have OIDs? */
        OnCommitAction oncommit;        /* what do we do at COMMIT? */
        char       *tablespacename; /* table space to use, or NULL */
} CreateStmt;

/* ----------
 * Definitions for plain (non-FOREIGN KEY) constraints in CreateStmt
 *
 * XXX probably these ought to be unified with FkConstraints at some point?
 * To this end we include CONSTR_FOREIGN in the ConstrType enum, even though
 * the parser does not generate it.
 *
 * For constraints that use expressions (CONSTR_DEFAULT, CONSTR_CHECK)
 * we may have the expression in either "raw" form (an untransformed
 * parse tree) or "cooked" form (the nodeToString representation of
 * an executable expression tree), depending on how this Constraint
 * node was created (by parsing, or by inheritance from an existing
 * relation).  We should never have both in the same node!
 *
 * Constraint attributes (DEFERRABLE etc) are initially represented as
 * separate Constraint nodes for simplicity of parsing.  analyze.c makes
 * a pass through the constraints list to attach the info to the appropriate
 * FkConstraint node (and, perhaps, someday to other kinds of constraints).
 * ----------
 */

typedef enum ConstrType                 /* types of constraints */
{
        CONSTR_NULL,                            /* not SQL92, but a lot of people expect it */
        CONSTR_NOTNULL,
        CONSTR_DEFAULT,
        CONSTR_CHECK,
        CONSTR_FOREIGN,
        CONSTR_PRIMARY,
        CONSTR_UNIQUE,
        CONSTR_ATTR_DEFERRABLE,         /* attributes for previous constraint node */
        CONSTR_ATTR_NOT_DEFERRABLE,
        CONSTR_ATTR_DEFERRED,
        CONSTR_ATTR_IMMEDIATE
} ConstrType;

typedef struct Constraint
{
        NodeTag         type;
        ConstrType      contype;
        char       *name;                       /* name, or NULL if unnamed */
        Node       *raw_expr;           /* expr, as untransformed parse tree */
        char       *cooked_expr;        /* expr, as nodeToString representation */
        List       *keys;                       /* String nodes naming referenced column(s) */
        char       *indexspace;         /* index tablespace for PKEY/UNIQUE
                                                                 * constraints; NULL for default */
} Constraint;

/* ----------
 * Definitions for FOREIGN KEY constraints in CreateStmt
 *
 * Note: FKCONSTR_ACTION_xxx values are stored into pg_constraint.confupdtype
 * and pg_constraint.confdeltype columns; FKCONSTR_MATCH_xxx values are
 * stored into pg_constraint.confmatchtype.  Changing the code values may
 * require an initdb!
 *
 * If skip_validation is true then we skip checking that the existing rows
 * in the table satisfy the constraint, and just install the catalog entries
 * for the constraint.  This is currently used only during CREATE TABLE
 * (when we know the table must be empty).
 * ----------
 */
#define FKCONSTR_ACTION_NOACTION        'a'
#define FKCONSTR_ACTION_RESTRICT        'r'
#define FKCONSTR_ACTION_CASCADE         'c'
#define FKCONSTR_ACTION_SETNULL         'n'
#define FKCONSTR_ACTION_SETDEFAULT      'd'

#define FKCONSTR_MATCH_FULL                     'f'
#define FKCONSTR_MATCH_PARTIAL          'p'
#define FKCONSTR_MATCH_UNSPECIFIED      'u'

typedef struct FkConstraint
{
        NodeTag         type;
        char       *constr_name;        /* Constraint name, or NULL if unnamed */
        RangeVar   *pktable;            /* Primary key table */
        List       *fk_attrs;           /* Attributes of foreign key */
        List       *pk_attrs;           /* Corresponding attrs in PK table */
        char            fk_matchtype;   /* FULL, PARTIAL, UNSPECIFIED */
        char            fk_upd_action;  /* ON UPDATE action */
        char            fk_del_action;  /* ON DELETE action */
        bool            deferrable;             /* DEFERRABLE */
        bool            initdeferred;   /* INITIALLY DEFERRED */
        bool            skip_validation;        /* skip validation of existing rows? */
} FkConstraint;


/* ----------------------
 *              Create/Drop Table Space Statements
 * ----------------------
 */

typedef struct CreateTableSpaceStmt
{
        NodeTag         type;
        char       *tablespacename;
        char       *owner;
        char       *location;
} CreateTableSpaceStmt;

typedef struct DropTableSpaceStmt
{
        NodeTag         type;
        char       *tablespacename;
} DropTableSpaceStmt;

/* ----------------------
 *              Create/Drop TRIGGER Statements
 * ----------------------
 */

typedef struct CreateTrigStmt
{
        NodeTag         type;
        char       *trigname;           /* TRIGGER's name */
        RangeVar   *relation;           /* relation trigger is on */
        List       *funcname;           /* qual. name of function to call */
        List       *args;                       /* list of (T_String) Values or NIL */
        bool            before;                 /* BEFORE/AFTER */
        bool            row;                    /* ROW/STATEMENT */
        char            actions[4];             /* 1 to 3 of 'i', 'u', 'd', + trailing \0 */

        /* The following are used for referential */
        /* integrity constraint triggers */
        bool            isconstraint;   /* This is an RI trigger */
        bool            deferrable;             /* [NOT] DEFERRABLE */
        bool            initdeferred;   /* INITIALLY {DEFERRED|IMMEDIATE} */
        RangeVar   *constrrel;          /* opposite relation */
} CreateTrigStmt;

/* ----------------------
 *              Create/Drop PROCEDURAL LANGUAGE Statement
 * ----------------------
 */
typedef struct CreatePLangStmt
{
        NodeTag         type;
        char       *plname;                     /* PL name */
        List       *plhandler;          /* PL call handler function (qual. name) */
        List       *plvalidator;        /* optional validator function (qual. name) */
        bool            pltrusted;              /* PL is trusted */
} CreatePLangStmt;

typedef struct DropPLangStmt
{
        NodeTag         type;
        char       *plname;                     /* PL name */
        DropBehavior behavior;          /* RESTRICT or CASCADE behavior */
} DropPLangStmt;

/* ----------------------
 *      Create/Alter/Drop Role Statements
 *
 * Note: these node types are also used for the backwards-compatible
 * Create/Alter/Drop User/Group statements.  In the ALTER and DROP cases
 * there's really no need to distinguish what the original spelling was,
 * but for CREATE we mark the type because the defaults vary.
 * ----------------------
 */
typedef enum RoleStmtType
{
        ROLESTMT_ROLE,
        ROLESTMT_USER,
        ROLESTMT_GROUP
} RoleStmtType;

typedef struct CreateRoleStmt
{
        NodeTag         type;
        RoleStmtType stmt_type;         /* ROLE/USER/GROUP */
        char       *role;                       /* role name */
        List       *options;            /* List of DefElem nodes */
} CreateRoleStmt;

typedef struct AlterRoleStmt
{
        NodeTag         type;
        char       *role;                       /* role name */
        List       *options;            /* List of DefElem nodes */
        int                     action;                 /* +1 = add members, -1 = drop members */
} AlterRoleStmt;

typedef struct AlterRoleSetStmt
{
        NodeTag         type;
        char       *role;                       /* role name */
        char       *variable;           /* GUC variable name */
        List       *value;                      /* value for variable, or NIL for Reset */
} AlterRoleSetStmt;

typedef struct DropRoleStmt
{
        NodeTag         type;
        List       *roles;                      /* List of roles to remove */
} DropRoleStmt;

/* ----------------------
 *              {Create|Alter} SEQUENCE Statement
 * ----------------------
 */

typedef struct CreateSeqStmt
{
        NodeTag         type;
        RangeVar   *sequence;           /* the sequence to create */
        List       *options;
} CreateSeqStmt;

typedef struct AlterSeqStmt
{
        NodeTag         type;
        RangeVar   *sequence;           /* the sequence to alter */
        List       *options;
} AlterSeqStmt;

/* ----------------------
 *              Create {Aggregate|Operator|Type} Statement
 * ----------------------
 */
typedef struct DefineStmt
{
        NodeTag         type;
        ObjectType      kind;                   /* aggregate, operator, type */
        List       *defnames;           /* qualified name (list of Value strings) */
        List       *definition;         /* a list of DefElem */
} DefineStmt;

/* ----------------------
 *              Create Domain Statement
 * ----------------------
 */
typedef struct CreateDomainStmt
{
        NodeTag         type;
        List       *domainname;         /* qualified name (list of Value strings) */
        TypeName   *typename;           /* the base type */
        List       *constraints;        /* constraints (list of Constraint nodes) */
} CreateDomainStmt;

/* ----------------------
 *              Create Operator Class Statement
 * ----------------------
 */
typedef struct CreateOpClassStmt
{
        NodeTag         type;
        List       *opclassname;        /* qualified name (list of Value strings) */
        char       *amname;                     /* name of index AM opclass is for */
        TypeName   *datatype;           /* datatype of indexed column */
        List       *items;                      /* List of CreateOpClassItem nodes */
        bool            isDefault;              /* Should be marked as default for type? */
} CreateOpClassStmt;

#define OPCLASS_ITEM_OPERATOR           1
#define OPCLASS_ITEM_FUNCTION           2
#define OPCLASS_ITEM_STORAGETYPE        3

typedef struct CreateOpClassItem
{
        NodeTag         type;
        int                     itemtype;               /* see codes above */
        /* fields used for an operator or function item: */
        List       *name;                       /* operator or function name */
        List       *args;                       /* argument types */
        int                     number;                 /* strategy num or support proc num */
        bool            recheck;                /* only used for operators */
        /* fields used for a storagetype item: */
        TypeName   *storedtype;         /* datatype stored in index */
} CreateOpClassItem;

/* ----------------------
 *              Drop Table|Sequence|View|Index|Type|Domain|Conversion|Schema Statement
 * ----------------------
 */

typedef struct DropStmt
{
        NodeTag         type;
        List       *objects;            /* list of sublists of names (as Values) */
        ObjectType      removeType;             /* object type */
        DropBehavior behavior;          /* RESTRICT or CASCADE behavior */
} DropStmt;

/* ----------------------
 *              Drop Rule|Trigger Statement
 *
 * In general this may be used for dropping any property of a relation;
 * for example, someday soon we may have DROP ATTRIBUTE.
 * ----------------------
 */

typedef struct DropPropertyStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* owning relation */
        char       *property;           /* name of rule, trigger, etc */
        ObjectType      removeType;             /* OBJECT_RULE or OBJECT_TRIGGER */
        DropBehavior behavior;          /* RESTRICT or CASCADE behavior */
} DropPropertyStmt;

/* ----------------------
 *                              Truncate Table Statement
 * ----------------------
 */
typedef struct TruncateStmt
{
        NodeTag         type;
        List       *relations;          /* relations (RangeVars) to be truncated */
} TruncateStmt;

/* ----------------------
 *                              Comment On Statement
 * ----------------------
 */
typedef struct CommentStmt
{
        NodeTag         type;
        ObjectType      objtype;                /* Object's type */
        List       *objname;            /* Qualified name of the object */
        List       *objargs;            /* Arguments if needed (eg, for functions) */
        char       *comment;            /* Comment to insert, or NULL to remove */
} CommentStmt;

/* ----------------------
 *              Declare Cursor Statement
 * ----------------------
 */
#define CURSOR_OPT_BINARY               0x0001
#define CURSOR_OPT_SCROLL               0x0002
#define CURSOR_OPT_NO_SCROLL    0x0004
#define CURSOR_OPT_INSENSITIVE  0x0008
#define CURSOR_OPT_HOLD                 0x0010

typedef struct DeclareCursorStmt
{
        NodeTag         type;
        char       *portalname;         /* name of the portal (cursor) */
        int                     options;                /* bitmask of options (see above) */
        Node       *query;                      /* the SELECT query */
} DeclareCursorStmt;

/* ----------------------
 *              Close Portal Statement
 * ----------------------
 */
typedef struct ClosePortalStmt
{
        NodeTag         type;
        char       *portalname;         /* name of the portal (cursor) */
} ClosePortalStmt;

/* ----------------------
 *              Fetch Statement (also Move)
 * ----------------------
 */
typedef enum FetchDirection
{
        /* for these, howMany is how many rows to fetch; FETCH_ALL means ALL */
        FETCH_FORWARD,
        FETCH_BACKWARD,
        /* for these, howMany indicates a position; only one row is fetched */
        FETCH_ABSOLUTE,
        FETCH_RELATIVE
} FetchDirection;

#define FETCH_ALL       LONG_MAX

typedef struct FetchStmt
{
        NodeTag         type;
        FetchDirection direction;       /* see above */
        long            howMany;                /* number of rows, or position argument */
        char       *portalname;         /* name of portal (cursor) */
        bool            ismove;                 /* TRUE if MOVE */
} FetchStmt;

/* ----------------------
 *              Create Index Statement
 * ----------------------
 */
typedef struct IndexStmt
{
        NodeTag         type;
        char       *idxname;            /* name of new index, or NULL for default */
        RangeVar   *relation;           /* relation to build index on */
        char       *accessMethod;       /* name of access method (eg. btree) */
        char       *tableSpace;         /* tablespace, or NULL to use parent's */
        List       *indexParams;        /* a list of IndexElem */
        Node       *whereClause;        /* qualification (partial-index predicate) */
        List       *rangetable;         /* range table for qual and/or expressions,
                                                                 * filled in by transformStmt() */
        bool            unique;                 /* is index unique? */
        bool            primary;                /* is index on primary key? */
        bool            isconstraint;   /* is it from a CONSTRAINT clause? */
} IndexStmt;

/* ----------------------
 *              Create Function Statement
 * ----------------------
 */
typedef struct CreateFunctionStmt
{
        NodeTag         type;
        bool            replace;                /* T => replace if already exists */
        List       *funcname;           /* qualified name of function to create */
        List       *parameters;         /* a list of FunctionParameter */
        TypeName   *returnType;         /* the return type */
        List       *options;            /* a list of DefElem */
        List       *withClause;         /* a list of DefElem */
} CreateFunctionStmt;

typedef enum FunctionParameterMode
{
        /* the assigned enum values appear in pg_proc, don't change 'em! */
        FUNC_PARAM_IN = 'i',            /* input only */
        FUNC_PARAM_OUT = 'o',           /* output only */
        FUNC_PARAM_INOUT = 'b'          /* both */
} FunctionParameterMode;

typedef struct FunctionParameter
{
        NodeTag         type;
        char       *name;                       /* parameter name, or NULL if not given */
        TypeName   *argType;            /* TypeName for parameter type */
        FunctionParameterMode mode; /* IN/OUT/INOUT */
} FunctionParameter;

typedef struct AlterFunctionStmt
{
        NodeTag         type;
        FuncWithArgs *func;                     /* name and args of function */
        List       *actions;            /* list of DefElem */
} AlterFunctionStmt;

/* ----------------------
 *              Drop Aggregate Statement
 * ----------------------
 */
typedef struct RemoveAggrStmt
{
        NodeTag         type;
        List       *aggname;            /* aggregate to drop */
        TypeName   *aggtype;            /* TypeName for input datatype, or NULL */
        DropBehavior behavior;          /* RESTRICT or CASCADE behavior */
} RemoveAggrStmt;

/* ----------------------
 *              Drop Function Statement
 * ----------------------
 */
typedef struct RemoveFuncStmt
{
        NodeTag         type;
        List       *funcname;           /* function to drop */
        List       *args;                       /* types of the arguments */
        DropBehavior behavior;          /* RESTRICT or CASCADE behavior */
} RemoveFuncStmt;

/* ----------------------
 *              Drop Operator Statement
 * ----------------------
 */
typedef struct RemoveOperStmt
{
        NodeTag         type;
        List       *opname;                     /* operator to drop */
        List       *args;                       /* types of the arguments */
        DropBehavior behavior;          /* RESTRICT or CASCADE behavior */
} RemoveOperStmt;

/* ----------------------
 *              Drop Operator Class Statement
 * ----------------------
 */
typedef struct RemoveOpClassStmt
{
        NodeTag         type;
        List       *opclassname;        /* qualified name (list of Value strings) */
        char       *amname;                     /* name of index AM opclass is for */
        DropBehavior behavior;          /* RESTRICT or CASCADE behavior */
} RemoveOpClassStmt;

/* ----------------------
 *              Alter Object Rename Statement
 * ----------------------
 */
typedef struct RenameStmt
{
        NodeTag         type;
        ObjectType      renameType;             /* OBJECT_TABLE, OBJECT_COLUMN, etc */
        RangeVar   *relation;           /* in case it's a table */
        List       *object;                     /* in case it's some other object */
        List       *objarg;                     /* argument types, if applicable */
        char       *subname;            /* name of contained object (column, rule,
                                                                 * trigger, etc) */
        char       *newname;            /* the new name */
} RenameStmt;

/* ----------------------
 *              ALTER object SET SCHEMA Statement
 * ----------------------
 */
typedef struct AlterObjectSchemaStmt
{
        NodeTag         type;
        ObjectType objectType;          /* OBJECT_TABLE, OBJECT_TYPE, etc */
        RangeVar   *relation;           /* in case it's a table */
        List       *object;                     /* in case it's some other object */
        List       *objarg;                     /* argument types, if applicable */
        char       *addname;            /* additional name if needed */
        char       *newschema;          /* the new schema */
} AlterObjectSchemaStmt;

/* ----------------------
 *              Alter Object Owner Statement
 * ----------------------
 */
typedef struct AlterOwnerStmt
{
        NodeTag         type;
        ObjectType objectType;          /* OBJECT_TABLE, OBJECT_TYPE, etc */
        RangeVar   *relation;           /* in case it's a table */
        List       *object;                     /* in case it's some other object */
        List       *objarg;                     /* argument types, if applicable */
        char       *addname;            /* additional name if needed */
        char       *newowner;           /* the new owner */
} AlterOwnerStmt;


/* ----------------------
 *              Create Rule Statement
 * ----------------------
 */
typedef struct RuleStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* relation the rule is for */
        char       *rulename;           /* name of the rule */
        Node       *whereClause;        /* qualifications */
        CmdType         event;                  /* SELECT, INSERT, etc */
        bool            instead;                /* is a 'do instead'? */
        List       *actions;            /* the action statements */
        bool            replace;                /* OR REPLACE */
} RuleStmt;

/* ----------------------
 *              Notify Statement
 * ----------------------
 */
typedef struct NotifyStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* qualified name to notify */
} NotifyStmt;

/* ----------------------
 *              Listen Statement
 * ----------------------
 */
typedef struct ListenStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* qualified name to listen on */
} ListenStmt;

/* ----------------------
 *              Unlisten Statement
 * ----------------------
 */
typedef struct UnlistenStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* qualified name to unlisten on, or '*' */
} UnlistenStmt;

/* ----------------------
 *              {Begin|Commit|Rollback} Transaction Statement
 * ----------------------
 */
typedef enum TransactionStmtKind
{
        TRANS_STMT_BEGIN,
        TRANS_STMT_START,                       /* semantically identical to BEGIN */
        TRANS_STMT_COMMIT,
        TRANS_STMT_ROLLBACK,
        TRANS_STMT_SAVEPOINT,
        TRANS_STMT_RELEASE,
        TRANS_STMT_ROLLBACK_TO,
        TRANS_STMT_PREPARE,
        TRANS_STMT_COMMIT_PREPARED,
        TRANS_STMT_ROLLBACK_PREPARED
} TransactionStmtKind;

typedef struct TransactionStmt
{
        NodeTag         type;
        TransactionStmtKind kind;       /* see above */
        List       *options;            /* for BEGIN/START and savepoint commands */
        char       *gid;                        /* for two-phase-commit related commands */
} TransactionStmt;

/* ----------------------
 *              Create Type Statement, composite types
 * ----------------------
 */
typedef struct CompositeTypeStmt
{
        NodeTag         type;
        RangeVar   *typevar;            /* the composite type to be created */
        List       *coldeflist;         /* list of ColumnDef nodes */
} CompositeTypeStmt;


/* ----------------------
 *              Create View Statement
 * ----------------------
 */
typedef struct ViewStmt
{
        NodeTag         type;
        RangeVar   *view;                       /* the view to be created */
        List       *aliases;            /* target column names */
        Query      *query;                      /* the SQL statement */
        bool            replace;                /* replace an existing view? */
} ViewStmt;

/* ----------------------
 *              Load Statement
 * ----------------------
 */
typedef struct LoadStmt
{
        NodeTag         type;
        char       *filename;           /* file to load */
} LoadStmt;

/* ----------------------
 *              Createdb Statement
 * ----------------------
 */
typedef struct CreatedbStmt
{
        NodeTag         type;
        char       *dbname;                     /* name of database to create */
        List       *options;            /* List of DefElem nodes */
} CreatedbStmt;

/* ----------------------
 *      Alter Database
 * ----------------------
 */
typedef struct AlterDatabaseStmt
{
        NodeTag         type;
        char       *dbname;                     /* name of database to alter */
        List       *options;            /* List of DefElem nodes */
} AlterDatabaseStmt;

typedef struct AlterDatabaseSetStmt
{
        NodeTag         type;
        char       *dbname;
        char       *variable;
        List       *value;
} AlterDatabaseSetStmt;

/* ----------------------
 *              Dropdb Statement
 * ----------------------
 */
typedef struct DropdbStmt
{
        NodeTag         type;
        char       *dbname;                     /* database to drop */
} DropdbStmt;

/* ----------------------
 *              Cluster Statement (support pbrown's cluster index implementation)
 * ----------------------
 */
typedef struct ClusterStmt
{
        NodeTag         type;
        RangeVar   *relation;           /* relation being indexed, or NULL if all */
        char       *indexname;          /* original index defined */
} ClusterStmt;

/* ----------------------
 *              Vacuum and Analyze Statements
 *
 * Even though these are nominally two statements, it's convenient to use
 * just one node type for both.
 * ----------------------
 */
typedef struct VacuumStmt
{
        NodeTag         type;
        bool            vacuum;                 /* do VACUUM step */
        bool            full;                   /* do FULL (non-concurrent) vacuum */
        bool            analyze;                /* do ANALYZE step */
        bool            freeze;                 /* early-freeze option */
        bool            verbose;                /* print progress info */
        RangeVar   *relation;           /* single table to process, or NULL */
        List       *va_cols;            /* list of column names, or NIL for all */
} VacuumStmt;

/* ----------------------
 *              Explain Statement
 * ----------------------
 */
typedef struct ExplainStmt
{
        NodeTag         type;
        Query      *query;                      /* the query */
        bool            verbose;                /* print plan info */
        bool            analyze;                /* get statistics by executing plan */
} ExplainStmt;

/* ----------------------
 * Checkpoint Statement
 * ----------------------
 */
typedef struct CheckPointStmt
{
        NodeTag         type;
} CheckPointStmt;

/* ----------------------
 * Set Statement
 * ----------------------
 */

typedef struct VariableSetStmt
{
        NodeTag         type;
        char       *name;
        List       *args;
        bool            is_local;               /* SET LOCAL */
} VariableSetStmt;

/* ----------------------
 * Show Statement
 * ----------------------
 */

typedef struct VariableShowStmt
{
        NodeTag         type;
        char       *name;
} VariableShowStmt;

/* ----------------------
 * Reset Statement
 * ----------------------
 */

typedef struct VariableResetStmt
{
        NodeTag         type;
        char       *name;
} VariableResetStmt;

/* ----------------------
 *              LOCK Statement
 * ----------------------
 */
typedef struct LockStmt
{
        NodeTag         type;
        List       *relations;          /* relations to lock */
        int                     mode;                   /* lock mode */
        bool            nowait;                 /* no wait mode */
} LockStmt;

/* ----------------------
 *              SET CONSTRAINTS Statement
 * ----------------------
 */
typedef struct ConstraintsSetStmt
{
        NodeTag         type;
        List       *constraints;        /* List of names as Value strings */
        bool            deferred;
} ConstraintsSetStmt;

/* ----------------------
 *              REINDEX Statement
 * ----------------------
 */
typedef struct ReindexStmt
{
        NodeTag         type;
        ObjectType      kind;                   /* OBJECT_INDEX, OBJECT_TABLE, OBJECT_DATABASE */
        RangeVar   *relation;           /* Table or index to reindex */
        const char *name;                       /* name of database to reindex */
        bool            do_system;              /* include system tables in database case */
        bool            do_user;                /* include user tables in database case */
} ReindexStmt;

/* ----------------------
 *              CREATE CONVERSION Statement
 * ----------------------
 */
typedef struct CreateConversionStmt
{
        NodeTag         type;
        List       *conversion_name;    /* Name of the conversion */
        char       *for_encoding_name;          /* source encoding name */
        char       *to_encoding_name;           /* destination encoding name */
        List       *func_name;          /* qualified conversion function name */
        bool            def;                    /* is this a default conversion? */
} CreateConversionStmt;

/* ----------------------
 *      CREATE CAST Statement
 * ----------------------
 */
typedef struct CreateCastStmt
{
        NodeTag         type;
        TypeName   *sourcetype;
        TypeName   *targettype;
        FuncWithArgs *func;
        CoercionContext context;
} CreateCastStmt;

/* ----------------------
 *      DROP CAST Statement
 * ----------------------
 */
typedef struct DropCastStmt
{
        NodeTag         type;
        TypeName   *sourcetype;
        TypeName   *targettype;
        DropBehavior behavior;
} DropCastStmt;


/* ----------------------
 *              PREPARE Statement
 * ----------------------
 */
typedef struct PrepareStmt
{
        NodeTag         type;
        char       *name;                       /* Name of plan, arbitrary */
        List       *argtypes;           /* Types of parameters (TypeNames) */
        List       *argtype_oids;       /* Types of parameters (OIDs) */
        Query      *query;                      /* The query itself */
} PrepareStmt;


/* ----------------------
 *              EXECUTE Statement
 * ----------------------
 */

typedef struct ExecuteStmt
{
        NodeTag         type;
        char       *name;                       /* The name of the plan to execute */
        RangeVar   *into;                       /* Optional table to store results in */
        List       *params;                     /* Values to assign to parameters */
} ExecuteStmt;


/* ----------------------
 *              DEALLOCATE Statement
 * ----------------------
 */
typedef struct DeallocateStmt
{
        NodeTag         type;
        char       *name;                       /* The name of the plan to remove */
} DeallocateStmt;

#endif   /* PARSENODES_H */