pg_constraint.h

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/*-------------------------------------------------------------------------
 *
 * pg_constraint.h
 *    definition of the system "constraint" relation (pg_constraint)
 *    along with the relation's initial contents.
 *
 *
 * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/catalog/pg_constraint.h
 *
 * NOTES
 *    the genbki.pl script reads this file and generates .bki
 *    information from the DATA() statements.
 *
 *-------------------------------------------------------------------------
 */
#ifndef PG_CONSTRAINT_H
#define PG_CONSTRAINT_H

#include "catalog/genbki.h"

/* ----------------
 *      pg_constraint definition.  cpp turns this into
 *      typedef struct FormData_pg_constraint
 * ----------------
 */
#define ConstraintRelationId  2606

CATALOG(pg_constraint,2606)
{
    /*
     * 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
     * SQL-spec 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? */
    bool        convalidated;   /* constraint has been validated? */

    /*
     * 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 */

    /*
     * conindid links to the index supporting the constraint, if any;
     * otherwise it's 0.  This is used for unique, primary-key, and exclusion
     * constraints, and less obviously for foreign-key constraints (where the
     * index is a unique index on the referenced relation's referenced
     * columns).  Notice that the index is on conrelid in the first case but
     * confrelid in the second.
     */
    Oid         conindid;       /* index supporting this constraint */

    /*
     * 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 */

    /* Has a local definition (hence, do not drop when coninhcount is 0) */
    bool        conislocal;

    /* Number of times inherited from direct parent relation(s) */
    int32       coninhcount;

    /* Has a local definition and cannot be inherited */
    bool        connoinherit;

#ifdef CATALOG_VARLEN           /* variable-length fields start here */

    /*
     * Columns of conrelid that the constraint applies to, if known (this is
     * NULL for trigger constraints)
     */
    int16       conkey[1];

    /*
     * If a foreign key, the referenced columns of confrelid
     */
    int16       confkey[1];

    /*
     * If a foreign key, the OIDs of the PK = FK equality operators for each
     * column of the constraint
     */
    Oid         conpfeqop[1];

    /*
     * If a foreign key, the OIDs of the PK = PK equality operators for each
     * column of the constraint (i.e., equality for the referenced columns)
     */
    Oid         conppeqop[1];

    /*
     * If a foreign key, the OIDs of the FK = FK equality operators for each
     * column of the constraint (i.e., equality for the referencing columns)
     */
    Oid         conffeqop[1];

    /*
     * If an exclusion constraint, the OIDs of the exclusion operators for
     * each column of the constraint
     */
    Oid         conexclop[1];

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

    /*
     * If a check constraint, source-text representation of expression
     */
    text        consrc;
#endif
} 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                 24
#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_convalidated     6
#define Anum_pg_constraint_conrelid         7
#define Anum_pg_constraint_contypid         8
#define Anum_pg_constraint_conindid         9
#define Anum_pg_constraint_confrelid        10
#define Anum_pg_constraint_confupdtype      11
#define Anum_pg_constraint_confdeltype      12
#define Anum_pg_constraint_confmatchtype    13
#define Anum_pg_constraint_conislocal       14
#define Anum_pg_constraint_coninhcount      15
#define Anum_pg_constraint_connoinherit     16
#define Anum_pg_constraint_conkey           17
#define Anum_pg_constraint_confkey          18
#define Anum_pg_constraint_conpfeqop        19
#define Anum_pg_constraint_conppeqop        20
#define Anum_pg_constraint_conffeqop        21
#define Anum_pg_constraint_conexclop        22
#define Anum_pg_constraint_conbin           23
#define Anum_pg_constraint_consrc           24

/* ----------------
 *      initial contents of pg_constraint
 * ----------------
 */

/* nothing, at present */


/* Valid values for contype */
#define CONSTRAINT_CHECK            'c'
#define CONSTRAINT_FOREIGN          'f'
#define CONSTRAINT_PRIMARY          'p'
#define CONSTRAINT_UNIQUE           'u'
#define CONSTRAINT_TRIGGER          't'
#define CONSTRAINT_EXCLUSION        'x'

/*
 * 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.
 */

#endif                          /* PG_CONSTRAINT_H */