使用PostgreSQL为表或视图创建备注的操作,备注,字段,我是,类型,视图

使用PostgreSQL为表或视图创建备注的操作

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1 为表和列创建备注

drop table if exists test;

create table test(

objectid serial not null,

num integer not null,

constraint pk_test_objectid primary key (objectid),

constraint ck_test_num check(num < 123 ),

);

comment on table test is '我是表';

comment on column test.objectid is '我是唯一主键';

comment on column test.num is '数量字段';

comment on constraint pk_test_objectid on test is '我是约束,唯一主键';

comment on constraint ck_test_num on test is '我是约束,num字段必须小于123';

\dS+ test;

2 为视图和列创建备注

drop view if exists vtest;

create or replace view vtest

as select 1 as col1, 'a' as col2, now() as col3;

comment on view vtest is '视图备注';

comment on column vtest.col1 is '第一列备注,integer类型';

comment on column vtest.col2 is '第二列备注,字符类型';

comment on column vtest.col3 is '第三列备注,日期时间类型';

3 comment语法

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 |

PUBLICATION object_name |

ROLE object_name |

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 'text'

where aggregate_signature is:

* |

[ argmode ] [ argname ] argtype [ , ... ] |

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

注意：SQL 标准中没有COMMENT命令。

补充：postgre 查询注释_PostgreSQL查询表以及字段的备注

查询所有表名称以及字段含义

select c.relname 表名,cast(obj_description(relfilenode,'pg_class') as varchar) 名称,a.attname 字段,d.description 字段备注,concat_ws('',t.typname,SUBSTRING(format_type(a.atttypid,a.atttypmod) from '.∗')) as 列类型 from pg_class c,pg_attribute a,pg_type t,pg_description d

where a.attnum>0 and a.attrelid=c.oid and a.atttypid=t.oid and d.objoid=a.attrelid and d.objsubid=a.attnum

and c.relname in (select tablename from pg_tables where schemaname='public' and position('_2' in tablename)=0) order by c.relname,a.attnum

查看所有表名

select tablename from pg_tables where schemaname='public' and position('_2' in tablename)=0;

select * from pg_tables;

查看表名和备注

select relname as tabname,cast(obj_description(relfilenode,'pg_class') as varchar) as comment from pg_class c

where relname in (select tablename from pg_tables where schemaname='public' and position('_2' in tablename)=0);

select * from pg_class;

查看特定表名备注

select relname as tabname,

cast(obj_description(relfilenode,'pg_class') as varchar) as comment from pg_class c

where relname ='表名';

查看特定表名字段

select a.attnum,a.attname,concat_ws('',t.typname,SUBSTRING(format_type(a.atttypid,a.atttypmod) from '.∗')) as type,d.description from pg_class c,pg_attribute a,pg_type t,pg_description d

where c.relname='表名' and a.attnum>0 and a.attrelid=c.oid and a.atttypid=t.oid and d.objoid=a.attrelid and d.objsubid=a.attnum;

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