parsenodes.h

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 *	  checkForRead, checkForWrite, and checkAsUser control run-time access
 *	  permissions checks.  A rel will be checked for read or write access
 *	  (or both, or neither) per checkForRead and checkForWrite.  If
 *	  checkAsUser is not InvalidOid, 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.
	 */
	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 */
	bool		checkForRead;	/* check rel for read access */
	bool		checkForWrite;	/* check rel for write access */
	Oid			checkAsUser;	/* if not zero, check access as this user */
} RangeTblEntry;

/*
 * SortClause -
 *	   representation of ORDER BY clauses
 *
 * tleSortGroupRef must match ressortgroupref of exactly one Resdom 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 Resdoms 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 */
} 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 struct SelectStmt
{
	NodeTag		type;

	/*
	 * These fields are used only in "leaf" SelectStmts.
	 *
	 * into and intoColNames 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 */
	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 */
	List	   *forUpdate;		/* FOR UPDATE clause */

	/*
	 * 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_GROUP,
	OBJECT_INDEX,
	OBJECT_LANGUAGE,
	OBJECT_OPCLASS,
	OBJECT_OPERATOR,
	OBJECT_RULE,
	OBJECT_SCHEMA,
	OBJECT_SEQUENCE,
	OBJECT_TABLE,
	OBJECT_TRIGGER,
	OBJECT_TYPE,
	OBJECT_USER,
	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
 *
 * The fields are used in different ways by the different variants of
 * this command.
 * ----------------------
 */
typedef struct AlterTableStmt
{
	NodeTag		type;
	char		subtype;		/*------------
								 *	A = add column
								 *	T = alter column default
								 *	N = alter column drop not null
								 *	n = alter column set not null
								 *	S = alter column statistics
								 *	M = alter column storage
								 *	D = drop column
								 *	C = add constraint
								 *	c = pre-processed add constraint
								 *		(local in parser/analyze.c)
								 *	X = drop constraint
								 *	E = create toast table
								 *	U = change owner
								 *	L = CLUSTER ON
								 *	o = DROP OIDS
								 *------------
								 */
	RangeVar   *relation;		/* table to work on */
	char	   *name;			/* column or constraint name to act on, or
								 * new owner */
	Node	   *def;			/* definition of new column or constraint */
	DropBehavior behavior;		/* RESTRICT or CASCADE for DROP cases */
} AlterTableStmt;

/* ----------------------
 *	Alter Domain
 *
 * The fields are used in different ways by the different variants of
 * this command. Subtypes should match AlterTable subtypes where possible.
 * ----------------------
 */
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
								 *	U = change owner
								 *------------
								 */
	List	   *typename;		/* table to work on */
	char	   *name;			/* column or constraint name to act on, or
								 * new owner */
	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 */
} GrantObjectType;

/*
 * Grantable rights are encoded so that we can OR them together in a bitmask.
 * The present representation of AclItem limits us to 15 distinct rights.
 * Caution: changing these codes breaks stored ACLs, hence forces initdb.
 */
#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_ALL_RIGHTS	(-1)	/* all-privileges marker in GRANT list */
#define ACL_NO_RIGHTS	0

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;		/* integer list of privilege codes */
	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	   *username;		/* if both are NULL then PUBLIC */
	char	   *groupname;
} PrivGrantee;

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;