SYSTEM CATALOG · 系统目录

pg_constraint

The catalog pg_constraint stores check, not-null, primary key, unique, foreign key, and exclusion constraints on tables. (Column constraints are not treated specially. Every column constraint is equivalent to some table constraint.) User-defined constraint triggers (created with CREATE CONSTRAINT TRIGGER) also give rise to an entry in this table. Check constraints on domains are stored here, too.

首次收录 PG 9.0最近收录 PG 19当前字段 28

9.0 9.1 9.2 9.3 9.4 9.5 9.6 10 11 12 13 14 15 16 17 18 19^β3

已与 PostgreSQL 18.6 实例逐字段核对 · 原始实测记录 ↗

字段结构 PostgreSQL 18

pg_constraint

字段 / COLUMN	类型 / TYPE	说明 / DESCRIPTION
`oid`	`oid`NOT NULL	Row identifier
`conname`	`name`NOT NULL	Constraint name (not necessarily unique!)
`connamespace`	`oid`NOT NULL	The OID of the namespace that contains this constraint引用：`pg_namespace.oid`
`contype`	`"char"`NOT NULL文档原写法：`char`	c = check constraint, f = foreign key constraint, n = not-null constraint, p = primary key constraint, u = unique constraint, t = constraint trigger, x = exclusion constraint
`condeferrable`	`boolean`NOT NULL文档原写法：`bool`	Is the constraint deferrable?
`condeferred`	`boolean`NOT NULL文档原写法：`bool`	Is the constraint deferred by default?
`conenforced`	`boolean`NOT NULL文档原写法：`bool`	Is the constraint enforced?
`convalidated`	`boolean`NOT NULL文档原写法：`bool`	Has the constraint been validated?
`conrelid`	`oid`NOT NULL	The table this constraint is on; zero if not a table constraint引用：`pg_class.oid`
`contypid`	`oid`NOT NULL	The domain this constraint is on; zero if not a domain constraint引用：`pg_type.oid`
`conindid`	`oid`NOT NULL	The index supporting this constraint, if it's a unique, primary key, foreign key, or exclusion constraint; else zero引用：`pg_class.oid`
`conparentid`	`oid`NOT NULL	The corresponding constraint of the parent partitioned table, if this is a constraint on a partition; else zero引用：`pg_constraint.oid`
`confrelid`	`oid`NOT NULL	If a foreign key, the referenced table; else zero引用：`pg_class.oid`
`confupdtype`	`"char"`NOT NULL文档原写法：`char`	Foreign key update action code: a = no action, r = restrict, c = cascade, n = set null, d = set default
`confdeltype`	`"char"`NOT NULL文档原写法：`char`	Foreign key deletion action code: a = no action, r = restrict, c = cascade, n = set null, d = set default
`confmatchtype`	`"char"`NOT NULL文档原写法：`char`	Foreign key match type: f = full, p = partial, s = simple
`conislocal`	`boolean`NOT NULL文档原写法：`bool`	This constraint is defined locally for the relation. Note that a constraint can be locally defined and inherited simultaneously.
`coninhcount`	`smallint`NOT NULL文档原写法：`int2`	The number of direct inheritance ancestors this constraint has. A constraint with a nonzero number of ancestors cannot be dropped nor renamed.
`connoinherit`	`boolean`NOT NULL文档原写法：`bool`	This constraint is defined locally for the relation. It is a non-inheritable constraint.
`conperiod`	`boolean`NOT NULL文档原写法：`bool`	This constraint is defined with WITHOUT OVERLAPS (for primary keys and unique constraints) or PERIOD (for foreign keys).
`conkey`	`smallint[]`文档原写法：`int2[]`	If a table constraint (including foreign keys, but not constraint triggers), list of the constrained columns引用：`pg_attribute.attnum`
`confkey`	`smallint[]`文档原写法：`int2[]`	If a foreign key, list of the referenced columns引用：`pg_attribute.attnum`
`conpfeqop`	`oid[]`	If a foreign key, list of the equality operators for PK = FK comparisons引用：`pg_operator.oid`
`conppeqop`	`oid[]`	If a foreign key, list of the equality operators for PK = PK comparisons引用：`pg_operator.oid`
`conffeqop`	`oid[]`	If a foreign key, list of the equality operators for FK = FK comparisons引用：`pg_operator.oid`
`confdelsetcols`	`smallint[]`文档原写法：`int2[]`	If a foreign key with a SET NULL or SET DEFAULT delete action, the columns that will be updated. If null, all of the referencing columns will be updated.引用：`pg_attribute.attnum`
`conexclop`	`oid[]`	If an exclusion constraint or WITHOUT OVERLAPS primary key/unique constraint, list of the per-column exclusion operators.引用：`pg_operator.oid`
`conbin`	`pg_node_tree`	If a check constraint, an internal representation of the expression. (It's recommended to use pg_get_constraintdef() to extract the definition of a check constraint.)

标记“隐式列”的字段不包含在 SELECT * 中；部分早期统计视图由同版本源码补全，额外来源会显示在字段说明中。

通用系统列 6

PostgreSQL 提供的系统属性，通常不在 SELECT * 中展开。单独保留，不与普通字段混算。

字段	类型	attnum
`tableoid`	`oid`	-6
`cmax`	`cid`	-5
`xmax`	`xid`	-4
`cmin`	`cid`	-3
`xmin`	`xid`	-2
`ctid`	`tid`	-1

字段演化矩阵

悬停查看字段类型

存在新增 / 类型或属性变化移除

字段 / COLUMN	9.0	9.1	9.2	9.3	9.4	9.5	9.6	10	11	12	13	14	15	16	17	18	19
`oid`
`conname`
`connamespace`
`contype`
`condeferrable`
`condeferred`
`conrelid`
`contypid`
`conindid`
`confrelid`
`confupdtype`
`confdeltype`
`confmatchtype`
`conislocal`
`coninhcount`
`conkey`
`confkey`
`conpfeqop`
`conppeqop`
`conffeqop`
`conexclop`
`conbin`
`consrc`										−	–	–	–	–	–	–	–
`convalidated`	–
`connoinherit`	–	–
`conparentid`	–	–	–	–	–	–	–	–
`confdelsetcols`	–	–	–	–	–	–	–	–	–	–	–	–
`conenforced`	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–
`conperiod`	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–

9.0 是收录基线；基线中已存在的字段不标记为新增。矩阵按字段名称对齐，重命名显示为旧字段移除与新字段新增。

演化时间线

相邻大版本的变化

PostgreSQL 18 ← 17

+ conenforced+ conperiod3 处字段说明更新目录说明更新

PostgreSQL 17 ← 16

1 处字段说明更新目录说明更新

PostgreSQL 16 ← 15

~ coninhcount: integer → smallint

PostgreSQL 15 ← 14

+ confdelsetcols

PostgreSQL 14 ← 13

6 处字段说明更新

PostgreSQL 12 ← 11

− consrc~ oid: 隐式列 → 常规列2 处字段说明更新

PostgreSQL 11 ← 10

+ conparentid

PostgreSQL 9.3 ← 9.2

2 处字段说明更新

PostgreSQL 9.2 ← 9.1

+ connoinherit1 处字段说明更新

PostgreSQL 9.1 ← 9.0

+ convalidated~ conbin: text → pg_node_tree

比较任意两个版本

起始版本 / FROM目标版本 / TO包含描述更新

选择两个版本，查看字段的新增、移除与类型变化。交互比较需要 JavaScript；演化时间线可直接阅读。