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SQL COMMAND · 其它对象

COMMENT

定义或修改对象的注释

define or change the comment of an object

COMMENT其它对象引入 7.0现存至 20 devel15 次语法变更

动词
COMMENT
对象
—
引入版本
7.0
状态
现存
语法变更次数
15
手册小节数
5

本站手册 · 18官方文档 ↗

版本轨迹

相对 PostgreSQL 17 语法未变，正文有更新。

语法铁道图 PostgreSQL 18

沿轨道从左向右阅读，分岔表示选择，绕行表示可选，回环表示重复。方框为参数，点击带下划线的参数可展开子规则。

COMMENT ON ACCESS METHOD object_name AGGREGATE aggregate_name ( aggregate_signature ) CAST ( source_type AS target_type ) COLLATION object_name COLUMN relation_name . column_name CONSTRAINT constraint_name ON table_name CONSTRAINT constraint_name ON DOMAIN domain_name CONVERSION object_name DATABASE object_name DOMAIN object_name EXTENSION object_name EVENT TRIGGER object_name FOREIGN DATA WRAPPER object_name FOREIGN TABLE object_name FUNCTION function_name ( argmode argname argtype , ) INDEX object_name LARGE OBJECT large_object_oid MATERIALIZED VIEW object_name OPERATOR operator_name ( left_type , right_type ) OPERATOR CLASS object_name USING index_method OPERATOR FAMILY object_name USING index_method POLICY policy_name ON table_name PROCEDURAL LANGUAGE object_name PROCEDURE procedure_name ( argmode argname argtype , ) PUBLICATION object_name ROLE object_name ROUTINE routine_name ( argmode argname argtype , ) RULE rule_name ON table_name SCHEMA object_name SEQUENCE object_name SERVER object_name STATISTICS object_name SUBSCRIPTION object_name TABLE object_name TABLESPACE object_name TEXT SEARCH CONFIGURATION object_name TEXT SEARCH DICTIONARY object_name TEXT SEARCH PARSER object_name TEXT SEARCH TEMPLATE object_name TRANSFORM FOR type_name LANGUAGE lang_name TRIGGER trigger_name ON table_name TYPE object_name VIEW object_name IS string_literal NULL
aggregate_signature
* argmode argname argtype , argmode argname argtype , ORDER BY argmode argname argtype ,

锁模式 PostgreSQL 18

具体锁模式取决于操作变体、目标对象和执行阶段；同一命令可同时取得表锁与行锁。查看完整冲突矩阵

SHARE UPDATE EXCLUSIVE · 表级锁

COMMENT ON（关系对象）：COMMENT 在所注释对象上取得此模式；不同对象上的同名锁不会互相冲突。

语法概要

COMMENT ON
{
ACCESS METHOD object_name |
AGGREGATE aggregate_name ( aggregate_signature ) |
CAST (source_type AS target_type) |
COLLATION object_name |
COLUMN relation_name.column_name |
CONSTRAINT constraint_name ON table_name |
CONSTRAINT constraint_name ON DOMAIN domain_name |
CONVERSION object_name |
DATABASE object_name |
DOMAIN object_name |
EXTENSION object_name |
EVENT TRIGGER object_name |
FOREIGN DATA WRAPPER object_name |
FOREIGN TABLE object_name |
FUNCTION function_name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ] |
INDEX object_name |
LARGE OBJECT large_object_oid |
MATERIALIZED VIEW object_name |
OPERATOR operator_name (left_type, right_type) |
OPERATOR CLASS object_name USING index_method |
OPERATOR FAMILY object_name USING index_method |
POLICY policy_name ON table_name |
[ PROCEDURAL ] LANGUAGE object_name |
PROCEDURE procedure_name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ] |
PUBLICATION object_name |
ROLE object_name |
ROUTINE routine_name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ] |
RULE rule_name ON table_name |
SCHEMA object_name |
SEQUENCE object_name |
SERVER object_name |
STATISTICS object_name |
SUBSCRIPTION object_name |
TABLE object_name |
TABLESPACE object_name |
TEXT SEARCH CONFIGURATION object_name |
TEXT SEARCH DICTIONARY object_name |
TEXT SEARCH PARSER object_name |
TEXT SEARCH TEMPLATE object_name |
TRANSFORM FOR type_name LANGUAGE lang_name |
TRIGGER trigger_name ON table_name |
TYPE object_name |
VIEW object_name
} IS { string_literal | NULL }

其中 aggregate_signature 是：

* |
[ argmode ] [ argname ] argtype [ , ... ] |
[ [ argmode ] [ argname ] argtype [ , ... ] ] ORDER BY [ argmode ] [ argname ] argtype [ , ... ]

PostgreSQL 18 手册 · 查看完整参考页

描述

COMMENT 用于存储、替换或移除数据库对象上的注释。

每个对象只存储一个注释字符串。对同一对象发出新的 COMMENT 命令会替换现有注释。指定 NULL 或空字符串（''）会移除注释。当对象被删除时，其注释也会自动删除。

将在要添加注释的对象上获取一个 SHARE UPDATE EXCLUSIVE 锁。

对于大多数对象类型，只有对象的拥有者才能设置注释。角色没有拥有者，因此 COMMENT ON ROLE 的规则是：若要为超级用户角色添加注释，你必须是超级用户；否则，你必须拥有 CREATEROLE 权限，并且在目标角色上已获授 ADMIN OPTION。同样，访问方法也没有拥有者；要为访问方法添加注释，你必须是超级用户。当然，超级用户可以为任何对象添加注释。

可以使用 psql 的\d 系列命令查看这些注释。其他用于检索注释的用户界面，也可以建立在 psql 使用的同一组内置函数之上，即 obj_description、col_description 和 shobj_description（见表 9.82）。

参数

object_name
relation_name.column_name
aggregate_name
constraint_name
function_name
operator_name
policy_name
procedure_name
routine_name
rule_name
trigger_name

要添加注释的对象名称。位于模式中的对象（表、函数等）的名称可以带模式限定。为列添加注释时，relation_name 必须引用一个表、视图、复合类型或外部表。

table_name
domain_name

当为约束、触发器、规则或策略创建注释时，这些参数指定定义该对象的表或域的名称。

source_type

该类型转换的源数据类型的名称。

target_type

该类型转换的目标数据类型的名称。

argmode

函数、过程或聚合函数参数的模式：IN、OUT、INOUT 或 VARIADIC。如果省略，默认值是 IN。注意 COMMENT 实际上并不关心 OUT 参数，因为确定函数标识只需要输入参数。因此，列出 IN、INOUT 和 VARIADIC 参数就足够了。

argname

函数、过程或聚合函数参数的名称。注意 COMMENT 实际上并不关心参数名称，因为确定函数标识只需要参数数据类型。

argtype

函数、过程或聚合函数参数的数据类型。

large_object_oid

大对象的 OID。

left_type
right_type

操作符参数的数据类型（可以是模式限定的）。对于前缀操作符缺失的参数，请写成 NONE。

PROCEDURAL

这是一个噪声词。

type_name

该转换的数据类型名称。

lang_name

该转换所用语言的名称。

string_literal

新的注释内容，以字符串字面量形式写成。空字符串（''）会移除该注释。

NULL

写入 NULL 以移除该注释。

注解

目前没有用于查看注释的安全机制：任何连接到某个数据库的用户都可以看到该数据库中所有对象的注释。对于数据库、角色和表空间这类共享对象，注释是全局存储的，因此连接到集簇中任一数据库的任何用户都可以看到共享对象的全部注释。因此，不要在注释中放入与安全密切相关的信息。

示例

为表 mytable 附加一条注释： 

COMMENT ON TABLE mytable IS 'This is my table.';

再将其移除： 

COMMENT ON TABLE mytable IS NULL;

更多示例： 

COMMENT ON ACCESS METHOD gin IS 'GIN index access method';
COMMENT ON AGGREGATE my_aggregate (double precision) IS 'Computes sample variance';
COMMENT ON CAST (text AS int4) IS 'Allow casts from text to int4';
COMMENT ON COLLATION "fr_CA" IS 'Canadian French';
COMMENT ON COLUMN my_table.my_column IS 'Employee ID number';
COMMENT ON CONVERSION my_conv IS 'Conversion to UTF8';
COMMENT ON CONSTRAINT bar_col_cons ON bar IS 'Constrains column col';
COMMENT ON CONSTRAINT dom_col_constr ON DOMAIN dom IS 'Constrains col of domain';
COMMENT ON DATABASE my_database IS 'Development Database';
COMMENT ON DOMAIN my_domain IS 'Email Address Domain';
COMMENT ON EVENT TRIGGER abort_ddl IS 'Aborts all DDL commands';
COMMENT ON EXTENSION hstore IS 'implements the hstore data type';
COMMENT ON FOREIGN DATA WRAPPER mywrapper IS 'my foreign data wrapper';
COMMENT ON FOREIGN TABLE my_foreign_table IS 'Employee Information in other database';
COMMENT ON FUNCTION my_function (timestamp) IS 'Returns Roman Numeral';
COMMENT ON INDEX my_index IS 'Enforces uniqueness on employee ID';
COMMENT ON LANGUAGE plpython IS 'Python support for stored procedures';
COMMENT ON LARGE OBJECT 346344 IS 'Planning document';
COMMENT ON MATERIALIZED VIEW my_matview IS 'Summary of order history';
COMMENT ON OPERATOR ^ (text, text) IS 'Performs intersection of two texts';
COMMENT ON OPERATOR - (NONE, integer) IS 'Unary minus';
COMMENT ON OPERATOR CLASS int4ops USING btree IS '4 byte integer operators for btrees';
COMMENT ON OPERATOR FAMILY integer_ops USING btree IS 'all integer operators for btrees';
COMMENT ON POLICY my_policy ON mytable IS 'Filter rows by users';
COMMENT ON PROCEDURE my_proc (integer, integer) IS 'Runs a report';
COMMENT ON PUBLICATION alltables IS 'Publishes all operations on all tables';
COMMENT ON ROLE my_role IS 'Administration group for finance tables';
COMMENT ON ROUTINE my_routine (integer, integer) IS 'Runs a routine (which is a function or procedure)';
COMMENT ON RULE my_rule ON my_table IS 'Logs updates of employee records';
COMMENT ON SCHEMA my_schema IS 'Departmental data';
COMMENT ON SEQUENCE my_sequence IS 'Used to generate primary keys';
COMMENT ON SERVER myserver IS 'my foreign server';
COMMENT ON STATISTICS my_statistics IS 'Improves planner row estimations';
COMMENT ON SUBSCRIPTION alltables IS 'Subscription for all operations on all tables';
COMMENT ON TABLE my_schema.my_table IS 'Employee Information';
COMMENT ON TABLESPACE my_tablespace IS 'Tablespace for indexes';
COMMENT ON TEXT SEARCH CONFIGURATION my_config IS 'Special word filtering';
COMMENT ON TEXT SEARCH DICTIONARY swedish IS 'Snowball stemmer for Swedish language';
COMMENT ON TEXT SEARCH PARSER my_parser IS 'Splits text into words';
COMMENT ON TEXT SEARCH TEMPLATE snowball IS 'Snowball stemmer';
COMMENT ON TRANSFORM FOR hstore LANGUAGE plpython3u IS 'Transform between hstore and Python dict';
COMMENT ON TRIGGER my_trigger ON my_table IS 'Used for RI';
COMMENT ON TYPE complex IS 'Complex number data type';
COMMENT ON VIEW my_view IS 'View of departmental costs';
COMMENT ON VIEW my_view IS NULL;

兼容性

SQL 标准中没有 COMMENT 命令。

语法演化

相邻大版本之间的差异，新的在前。版本号链接到对应快照。

  1. PostgreSQL 19← 18正文更新

    正文更新

  2. PostgreSQL 18← 17正文更新

    正文更新

  3. PostgreSQL 17← 16正文更新

    正文更新

  4. PostgreSQL 16← 15正文更新

    正文更新

  5. PostgreSQL 15← 14正文更新

    正文更新

  6. PostgreSQL 14← 13正文更新

    正文更新

  7. PostgreSQL 12← 11正文更新

    正文更新

  8. PostgreSQL 11← 10语法变化

    + PROCEDURE procedure_name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ] |+ ROLE object_name |+ ROUTINE routine_name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ] |+ } IS { string_literal | NULL }− } IS 'text'正文更新

  9. PostgreSQL 10← 9.6语法变化

    + FUNCTION function_name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ] |+ PUBLICATION object_name |+ SERVER object_name |+ STATISTICS object_name |+ SUBSCRIPTION object_name |正文更新

  10. PostgreSQL 9.6← 9.5语法变化

    + ACCESS METHOD object_name |正文更新

  11. PostgreSQL 9.5← 9.4语法变化

    + CONSTRAINT constraint_name ON table_name |+ CONSTRAINT constraint_name ON DOMAIN domain_name |+ POLICY policy_name ON table_name |+ TEXT SEARCH TEMPLATE object_name |+ TRANSFORM FOR type_name LANGUAGE lang_name |正文更新

  12. PostgreSQL 9.4← 9.3语法变化

    + AGGREGATE aggregate_name ( aggregate_signature ) |+ * |+ [ argmode ] [ argname ] argtype [ , ... ] |+ [ [ argmode ] [ argname ] argtype [ , ... ] ] ORDER BY [ argmode ] [ argname ] argtype [ , ... ]− AGGREGATE agg_name (agg_type [, ...] ) |正文更新

  13. PostgreSQL 9.3← 9.2语法变化

    + EVENT TRIGGER object_name |+ LARGE OBJECT large_object_oid |+ MATERIALIZED VIEW object_name |正文更新

  14. PostgreSQL 9.2← 9.1正文更新

    正文更新

  15. PostgreSQL 9.1← 9.0语法变化

    + COLLATION object_name |+ DOMAIN object_name |+ EXTENSION object_name |+ FOREIGN DATA WRAPPER object_name |+ FOREIGN TABLE object_name |+ SERVER object_name |+ TABLE object_name |− TABLE object_name |正文更新

  16. PostgreSQL 9.0← 8.4语法变化

    + CAST (source_type AS target_type) |+ COLUMN relation_name.column_name |+ FUNCTION function_name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) |+ OPERATOR operator_name (left_type, right_type) |− TABLE object_name |− COLUMN table_name.column_name |− CAST (sourcetype AS targettype) |− FUNCTION func_name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) |− OPERATOR op (leftoperand_type, rightoperand_type) |正文更新

  17. PostgreSQL 8.4← 8.3正文更新

    正文更新

  18. PostgreSQL 8.3← 8.2语法变化

    + OPERATOR FAMILY object_name USING index_method |+ TEXT SEARCH CONFIGURATION object_name |+ TEXT SEARCH DICTIONARY object_name |+ TEXT SEARCH PARSER object_name |+ TEXT SEARCH TEMPLATE object_name |正文更新

  19. PostgreSQL 8.2← 8.1语法变化

    + AGGREGATE agg_name (agg_type [, ...] ) |+ ROLE object_name |+ SEQUENCE object_name |+ TABLESPACE object_name |正文更新

  20. PostgreSQL 8.1← 8.0语法变化

    + FUNCTION func_name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) |− FUNCTION func_name (arg1_type, arg2_type, ...) |正文更新

  21. PostgreSQL 8.0← 7.4语法变化

    + CAST (sourcetype AS targettype) |+ CONSTRAINT constraint_name ON table_name |+ CONVERSION object_name |+ LARGE OBJECT large_object_oid |+ OPERATOR op (leftoperand_type, rightoperand_type) |+ OPERATOR CLASS object_name USING index_method |+ [ PROCEDURAL ] LANGUAGE object_name |正文更新

  22. PostgreSQL 7.4← 7.3语法变化

    + {+ } IS 'text'− [− ] IS 'text'正文更新

  23. PostgreSQL 7.3← 7.2语法变化

    + CONSTRAINT constraint_name ON table_name |+ DATABASE object_name |+ DOMAIN object_name |+ FUNCTION func_name (arg1_type, arg2_type, ...) |+ INDEX object_name |+ OPERATOR op (leftoperand_type, rightoperand_type) |+ RULE rule_name ON table_name |+ SCHEMA object_name |+ SEQUENCE object_name |+ TRIGGER trigger_name ON table_name |+ TYPE object_name |+ VIEW object_name− [ DATABASE | INDEX | RULE | SEQUENCE | TABLE | TYPE | VIEW ] object_name |− FUNCTION func_name (arg1, arg2, ...) |正文更新

  24. PostgreSQL 7.2← 7.1语法变化

    + AGGREGATE agg_name (agg_type) |正文更新

  25. PostgreSQL 7.1← 7.0文件改名

    sql-comment.htm → sql-comment.html

    正文更新

  26. PostgreSQL 7.0← 6.5新增此命令

同组命令

命令动词对象版本变动最近变更
OTHER OBJECTS其它对象3 条↑
COMMENTCOMMENT— 1115 次
定义或修改对象的注释现存
REPACKREPACK— —
重写表以回收磁盘空间现存
ALTER LARGE OBJECTALTERLARGE OBJECT 142 次
更改一个大对象的定义现存