目录

pg_event_trigger

存储事件触发器信息的系统表

pg_event_trigger 是一个 系统目录表，存储关于 事件触发器的信息。

pg_event_trigger 在 PostgreSQL 9.3 中添加。

psql 命令

\dy 列出可用的事件触发器。

按 PostgreSQL 版本定义

pg_event_trigger (PostgreSQL 19)

         Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Collation | Nullable | Default 
------------+--------+-----------+----------+---------
 oid        | oid    |           | not null | 
 evtname    | name   |           | not null | 
 evtevent   | name   |           | not null | 
 evtowner   | oid    |           | not null | 
 evtfoid    | oid    |           | not null | 
 evtenabled | "char" |           | not null | 
 evttags    | text[] | C         |          | 
Indexes:
    "pg_event_trigger_oid_index" PRIMARY KEY, btree (oid)
    "pg_event_trigger_evtname_index" UNIQUE CONSTRAINT, btree (evtname)

文档: pg_event_trigger

pg_event_trigger (PostgreSQL 18)

         Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Collation | Nullable | Default 
------------+--------+-----------+----------+---------
 oid        | oid    |           | not null | 
 evtname    | name   |           | not null | 
 evtevent   | name   |           | not null | 
 evtowner   | oid    |           | not null | 
 evtfoid    | oid    |           | not null | 
 evtenabled | "char" |           | not null | 
 evttags    | text[] | C         |          | 
Indexes:
    "pg_event_trigger_oid_index" PRIMARY KEY, btree (oid)
    "pg_event_trigger_evtname_index" UNIQUE CONSTRAINT, btree (evtname)

文档: pg_event_trigger

pg_event_trigger (PostgreSQL 17)

         Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Collation | Nullable | Default 
------------+--------+-----------+----------+---------
 oid        | oid    |           | not null | 
 evtname    | name   |           | not null | 
 evtevent   | name   |           | not null | 
 evtowner   | oid    |           | not null | 
 evtfoid    | oid    |           | not null | 
 evtenabled | "char" |           | not null | 
 evttags    | text[] | C         |          | 
Indexes:
    "pg_event_trigger_oid_index" PRIMARY KEY, btree (oid)
    "pg_event_trigger_evtname_index" UNIQUE CONSTRAINT, btree (evtname)

文档: pg_event_trigger

pg_event_trigger (PostgreSQL 16)

         Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Collation | Nullable | Default 
------------+--------+-----------+----------+---------
 oid        | oid    |           | not null | 
 evtname    | name   |           | not null | 
 evtevent   | name   |           | not null | 
 evtowner   | oid    |           | not null | 
 evtfoid    | oid    |           | not null | 
 evtenabled | "char" |           | not null | 
 evttags    | text[] | C         |          | 
Indexes:
    "pg_event_trigger_oid_index" PRIMARY KEY, btree (oid)
    "pg_event_trigger_evtname_index" UNIQUE CONSTRAINT, btree (evtname)

文档: pg_event_trigger

pg_event_trigger (PostgreSQL 15)

         Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Collation | Nullable | Default 
------------+--------+-----------+----------+---------
 oid        | oid    |           | not null | 
 evtname    | name   |           | not null | 
 evtevent   | name   |           | not null | 
 evtowner   | oid    |           | not null | 
 evtfoid    | oid    |           | not null | 
 evtenabled | "char" |           | not null | 
 evttags    | text[] | C         |          | 
Indexes:
    "pg_event_trigger_oid_index" PRIMARY KEY, btree (oid)
    "pg_event_trigger_evtname_index" UNIQUE CONSTRAINT, btree (evtname)

文档: pg_event_trigger

pg_event_trigger (PostgreSQL 14)

         Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Collation | Nullable | Default 
------------+--------+-----------+----------+---------
 oid        | oid    |           | not null | 
 evtname    | name   |           | not null | 
 evtevent   | name   |           | not null | 
 evtowner   | oid    |           | not null | 
 evtfoid    | oid    |           | not null | 
 evtenabled | "char" |           | not null | 
 evttags    | text[] | C         |          | 
Indexes:
    "pg_event_trigger_oid_index" PRIMARY KEY, btree (oid)
    "pg_event_trigger_evtname_index" UNIQUE CONSTRAINT, btree (evtname)

文档: pg_event_trigger

pg_event_trigger (PostgreSQL 13)

         Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Collation | Nullable | Default 
------------+--------+-----------+----------+---------
 oid        | oid    |           | not null | 
 evtname    | name   |           | not null | 
 evtevent   | name   |           | not null | 
 evtowner   | oid    |           | not null | 
 evtfoid    | oid    |           | not null | 
 evtenabled | "char" |           | not null | 
 evttags    | text[] | C         |          | 
Indexes:
    "pg_event_trigger_evtname_index" UNIQUE, btree (evtname)
    "pg_event_trigger_oid_index" UNIQUE, btree (oid)

文档: pg_event_trigger

pg_event_trigger (PostgreSQL 12)

         Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Collation | Nullable | Default 
------------+--------+-----------+----------+---------
 oid        | oid    |           | not null | 
 evtname    | name   |           | not null | 
 evtevent   | name   |           | not null | 
 evtowner   | oid    |           | not null | 
 evtfoid    | oid    |           | not null | 
 evtenabled | "char" |           | not null | 
 evttags    | text[] | C         |          | 
Indexes:
    "pg_event_trigger_evtname_index" UNIQUE, btree (evtname)
    "pg_event_trigger_oid_index" UNIQUE, btree (oid)

文档: pg_event_trigger

pg_event_trigger (PostgreSQL 11)

         Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Collation | Nullable | Default 
------------+--------+-----------+----------+---------
 evtname    | name   |           | not null | 
 evtevent   | name   |           | not null | 
 evtowner   | oid    |           | not null | 
 evtfoid    | oid    |           | not null | 
 evtenabled | "char" |           | not null | 
 evttags    | text[] |           |          | 
Indexes:
    "pg_event_trigger_evtname_index" UNIQUE, btree (evtname)
    "pg_event_trigger_oid_index" UNIQUE, btree (oid)

文档: pg_event_trigger

pg_event_trigger (PostgreSQL 10)

         Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Collation | Nullable | Default 
------------+--------+-----------+----------+---------
 evtname    | name   |           | not null | 
 evtevent   | name   |           | not null | 
 evtowner   | oid    |           | not null | 
 evtfoid    | oid    |           | not null | 
 evtenabled | "char" |           | not null | 
 evttags    | text[] |           |          | 
Indexes:
    "pg_event_trigger_evtname_index" UNIQUE, btree (evtname)
    "pg_event_trigger_oid_index" UNIQUE, btree (oid)

文档: pg_event_trigger

pg_event_trigger (PostgreSQL 9.6)

Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Modifiers 
------------+--------+-----------
 evtname    | name   | not null
 evtevent   | name   | not null
 evtowner   | oid    | not null
 evtfoid    | oid    | not null
 evtenabled | "char" | not null
 evttags    | text[] | 
Indexes:
    "pg_event_trigger_evtname_index" UNIQUE, btree (evtname)
    "pg_event_trigger_oid_index" UNIQUE, btree (oid)

文档: pg_event_trigger

pg_event_trigger (PostgreSQL 9.5)

Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Modifiers 
------------+--------+-----------
 evtname    | name   | not null
 evtevent   | name   | not null
 evtowner   | oid    | not null
 evtfoid    | oid    | not null
 evtenabled | "char" | not null
 evttags    | text[] | 
Indexes:
    "pg_event_trigger_evtname_index" UNIQUE, btree (evtname)
    "pg_event_trigger_oid_index" UNIQUE, btree (oid)

文档: pg_event_trigger

pg_event_trigger (PostgreSQL 9.4)

Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Modifiers 
------------+--------+-----------
 evtname    | name   | not null
 evtevent   | name   | not null
 evtowner   | oid    | not null
 evtfoid    | oid    | not null
 evtenabled | "char" | not null
 evttags    | text[] | 
Indexes:
    "pg_event_trigger_evtname_index" UNIQUE, btree (evtname)
    "pg_event_trigger_oid_index" UNIQUE, btree (oid)

文档: pg_event_trigger

pg_event_trigger (PostgreSQL 9.3)

Table "pg_catalog.pg_event_trigger"
   Column   |  Type  | Modifiers 
------------+--------+-----------
 evtname    | name   | not null
 evtevent   | name   | not null
 evtowner   | oid    | not null
 evtfoid    | oid    | not null
 evtenabled | "char" | not null
 evttags    | text[] | 
Indexes:
    "pg_event_trigger_evtname_index" UNIQUE, btree (evtname)
    "pg_event_trigger_oid_index" UNIQUE, btree (oid)

文档: pg_event_trigger

变更历史

自 PostgreSQL 9.3 添加以来，此表未被修改。

示例

使用以下（人为构造的）示例，该示例创建一个 事件触发器，阻止任何名为 foo 的对象被删除。

CREATE OR REPLACE FUNCTION do_not_drop_foo()
  RETURNS event_trigger
 LANGUAGE plpgsql
  AS $$
BEGIN
  PERFORM * FROM pg_catalog.pg_event_trigger_dropped_objects() WHERE object_name = 'foo';
  IF FOUND THEN
    RAISE EXCEPTION 'objects named ''foo'' may not be dropped';
  END IF;
END;
$$;

CREATE EVENT TRIGGER prevent_foo_drop ON sql_drop
   EXECUTE FUNCTION do_not_drop_foo();

pg_event_trigger 的填充如下：

postgres=# SELECT * FROM pg_event_trigger ;
  oid  |     evtname      | evtevent | evtowner | evtfoid | evtenabled | evttags 
-------+------------------+----------+----------+---------+------------+---------
 16463 | prevent_foo_drop | sql_drop |       10 |   16455 | O          | 
(1 row)

postgres=# \dy
                          List of event triggers
       Name       |  Event   |  Owner   | Enabled |    Function     | Tags 
------------------+----------+----------+---------+-----------------+------
 prevent_foo_drop | sql_drop | postgres | enabled | do_not_drop_foo | 
(1 row)

分类

DDL, 系统目录, 触发器

另请参阅

事件触发器, CREATE EVENT TRIGGER

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