pg_constraint.h

来自「PostgreSQL7.4.6 for Linux」· C头文件 代码 · 共 186 行

/*-------------------------------------------------------------------------
 *
 * pg_constraint.h
 *	  definition of the system "constraint" relation (pg_constraint)
 *	  along with the relation's initial contents.
 *
 *
 * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $Id: pg_constraint.h,v 1.9 2003/08/08 21:42:32 momjian Exp $
 *
 * NOTES
 *	  the genbki.sh script reads this file and generates .bki
 *	  information from the DATA() statements.
 *
 *-------------------------------------------------------------------------
 */
#ifndef PG_CONSTRAINT_H
#define PG_CONSTRAINT_H

/* ----------------
 *		postgres.h contains the system type definitions and the
 *		CATALOG(), BOOTSTRAP and DATA() sugar words so this file
 *		can be read by both genbki.sh and the C compiler.
 * ----------------
 */

/* ----------------
 *		pg_constraint definition.  cpp turns this into
 *		typedef struct FormData_pg_constraint
 * ----------------
 */
CATALOG(pg_constraint)
{
	/*
	 * conname + connamespace is deliberately not unique; we allow, for
	 * example, the same name to be used for constraints of different
	 * relations.  This is partly for backwards compatibility with past
	 * Postgres practice, and partly because we don't want to have to
	 * obtain a global lock to generate a globally unique name for a
	 * nameless constraint.  We associate a namespace with constraint
	 * names only for SQL92 compatibility.
	 */
	NameData	conname;		/* name of this constraint */
	Oid			connamespace;	/* OID of namespace containing constraint */
	char		contype;		/* constraint type; see codes below */
	bool		condeferrable;	/* deferrable constraint? */
	bool		condeferred;	/* deferred by default? */

	/*
	 * conrelid and conkey are only meaningful if the constraint applies
	 * to a specific relation (this excludes domain constraints and
	 * assertions).  Otherwise conrelid is 0 and conkey is NULL.
	 */
	Oid			conrelid;		/* relation this constraint constrains */

	/*
	 * contypid links to the pg_type row for a domain if this is a domain
	 * constraint.	Otherwise it's 0.
	 *
	 * For SQL-style global ASSERTIONs, both conrelid and contypid would be
	 * zero.  This is not presently supported, however.
	 */
	Oid			contypid;		/* domain this constraint constrains */

	/*
	 * These fields, plus confkey, are only meaningful for a foreign-key
	 * constraint.	Otherwise confrelid is 0 and the char fields are
	 * spaces.
	 */
	Oid			confrelid;		/* relation referenced by foreign key */
	char		confupdtype;	/* foreign key's ON UPDATE action */
	char		confdeltype;	/* foreign key's ON DELETE action */
	char		confmatchtype;	/* foreign key's match type */

	/*
	 * VARIABLE LENGTH FIELDS start here.  These fields may be NULL, too.
	 */

	/*
	 * Columns of conrelid that the constraint applies to
	 */
	int2		conkey[1];

	/*
	 * If a foreign key, the referenced columns of confrelid
	 */
	int2		confkey[1];

	/*
	 * If a check constraint, nodeToString representation of expression
	 */
	text		conbin;

	/*
	 * If a check constraint, source-text representation of expression
	 */
	text		consrc;
} FormData_pg_constraint;

/* ----------------
 *		Form_pg_constraint corresponds to a pointer to a tuple with
 *		the format of pg_constraint relation.
 * ----------------
 */
typedef FormData_pg_constraint *Form_pg_constraint;

/* ----------------
 *		compiler constants for pg_constraint
 * ----------------
 */
#define Natts_pg_constraint					15
#define Anum_pg_constraint_conname			1
#define Anum_pg_constraint_connamespace		2
#define Anum_pg_constraint_contype			3
#define Anum_pg_constraint_condeferrable	4
#define Anum_pg_constraint_condeferred		5
#define Anum_pg_constraint_conrelid			6
#define Anum_pg_constraint_contypid			7
#define Anum_pg_constraint_confrelid		8
#define Anum_pg_constraint_confupdtype		9
#define Anum_pg_constraint_confdeltype		10
#define Anum_pg_constraint_confmatchtype	11
#define Anum_pg_constraint_conkey			12
#define Anum_pg_constraint_confkey			13
#define Anum_pg_constraint_conbin			14
#define Anum_pg_constraint_consrc			15


/* Valid values for contype */
#define CONSTRAINT_CHECK			'c'
#define CONSTRAINT_FOREIGN			'f'
#define CONSTRAINT_PRIMARY			'p'
#define CONSTRAINT_UNIQUE			'u'

/*
 * Valid values for confupdtype and confdeltype are the FKCONSTR_ACTION_xxx
 * constants defined in parsenodes.h.  Valid values for confmatchtype are
 * the FKCONSTR_MATCH_xxx constants defined in parsenodes.h.
 */

/*
 * Used for constraint support functions where the
 * and conrelid, contypid columns being looked up
 */
typedef enum CONSTRAINTCATEGORY
{
	CONSTRAINT_RELATION,
	CONSTRAINT_DOMAIN,
	CONSTRAINT_ASSERTION
} CONSTRAINTCATEGORY;

/*
 * prototypes for functions in pg_constraint.c
 */
extern Oid CreateConstraintEntry(const char *constraintName,
					  Oid constraintNamespace,
					  char constraintType,
					  bool isDeferrable,
					  bool isDeferred,
					  Oid relId,
					  const int16 *constraintKey,
					  int constraintNKeys,
					  Oid domainId,
					  Oid foreignRelId,
					  const int16 *foreignKey,
					  int foreignNKeys,
					  char foreignUpdateType,
					  char foreignDeleteType,
					  char foreignMatchType,
					  Oid indexRelId,
					  Node *conExpr,
					  const char *conBin,
					  const char *conSrc);

extern void RemoveConstraintById(Oid conId);

extern bool ConstraintNameIsUsed(CONSTRAINTCATEGORY conCat, Oid objId, Oid objNamespace,
					 const char *cname);
extern char *GenerateConstraintName(CONSTRAINTCATEGORY conCat, Oid objId, Oid objNamespace,
					   int *counter);
extern bool ConstraintNameIsGenerated(const char *cname);

#endif   /* PG_CONSTRAINT_H */