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62f34097c8
This follows in the spirit of commit dfb75e478, which created primary
key and uniqueness constraints to improve the visibility of constraints
imposed on the system catalogs. While our catalogs contain many
foreign-key-like relationships, they don't quite follow SQL semantics,
in that the convention for an omitted reference is to write zero not
NULL. Plus, we have some cases in which there are arrays each of whose
elements is supposed to be an FK reference; SQL has no way to model that.
So we can't create actual foreign key constraints to describe the
situation. Nonetheless, we can collect and use knowledge about these
relationships.
This patch therefore adds annotations to the catalog header files to
declare foreign-key relationships. (The BKI_LOOKUP annotations cover
simple cases, but we weren't previously distinguishing which such
columns are allowed to contain zeroes; we also need new markings for
multi-column FK references.) Then, Catalog.pm and genbki.pl are
taught to collect this information into a table in a new generated
header "system_fk_info.h". The only user of that at the moment is
a new SQL function pg_get_catalog_foreign_keys(), which exposes the
table to SQL. The oidjoins regression test is rewritten to use
pg_get_catalog_foreign_keys() to find out which columns to check.
Aside from removing the need for manual maintenance of that test
script, this allows it to cover numerous relationships that were not
checked by the old implementation based on findoidjoins. (As of this
commit, 217 relationships are checked by the test, versus 181 before.)
Discussion: https://postgr.es/m/3240355.1612129197@sss.pgh.pa.us
69 lines
2.3 KiB
C
69 lines
2.3 KiB
C
/*-------------------------------------------------------------------------
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*
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* pg_enum.h
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* definition of the "enum" system catalog (pg_enum)
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*
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*
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* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/catalog/pg_enum.h
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*
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* NOTES
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* The Catalog.pm module reads this file and derives schema
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* information.
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef PG_ENUM_H
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#define PG_ENUM_H
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#include "catalog/genbki.h"
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#include "catalog/pg_enum_d.h"
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#include "nodes/pg_list.h"
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/* ----------------
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* pg_enum definition. cpp turns this into
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* typedef struct FormData_pg_enum
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* ----------------
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*/
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CATALOG(pg_enum,3501,EnumRelationId)
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{
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Oid oid; /* oid */
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Oid enumtypid BKI_LOOKUP(pg_type); /* OID of owning enum type */
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float4 enumsortorder; /* sort position of this enum value */
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NameData enumlabel; /* text representation of enum value */
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} FormData_pg_enum;
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/* ----------------
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* Form_pg_enum corresponds to a pointer to a tuple with
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* the format of pg_enum relation.
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* ----------------
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*/
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typedef FormData_pg_enum *Form_pg_enum;
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DECLARE_UNIQUE_INDEX_PKEY(pg_enum_oid_index, 3502, on pg_enum using btree(oid oid_ops));
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#define EnumOidIndexId 3502
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DECLARE_UNIQUE_INDEX(pg_enum_typid_label_index, 3503, on pg_enum using btree(enumtypid oid_ops, enumlabel name_ops));
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#define EnumTypIdLabelIndexId 3503
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DECLARE_UNIQUE_INDEX(pg_enum_typid_sortorder_index, 3534, on pg_enum using btree(enumtypid oid_ops, enumsortorder float4_ops));
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#define EnumTypIdSortOrderIndexId 3534
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/*
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* prototypes for functions in pg_enum.c
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*/
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extern void EnumValuesCreate(Oid enumTypeOid, List *vals);
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extern void EnumValuesDelete(Oid enumTypeOid);
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extern void AddEnumLabel(Oid enumTypeOid, const char *newVal,
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const char *neighbor, bool newValIsAfter,
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bool skipIfExists);
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extern void RenameEnumLabel(Oid enumTypeOid,
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const char *oldVal, const char *newVal);
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extern bool EnumUncommitted(Oid enum_id);
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extern Size EstimateUncommittedEnumsSpace(void);
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extern void SerializeUncommittedEnums(void *space, Size size);
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extern void RestoreUncommittedEnums(void *space);
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extern void AtEOXact_Enum(void);
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#endif /* PG_ENUM_H */
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