今天就跟大家聊聊有关怎么在PostgreSQL中为表或视图创建备注,可能很多人都不太了解,为了让大家更加了解,小编给大家总结了以下内容,希望大家根据这篇文章可以有所收获。
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;
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';
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;
看完上述内容,你们对怎么在PostgreSQL中为表或视图创建备注有进一步的了解吗?如果还想了解更多知识或者相关内容,请关注亿速云行业资讯频道,感谢大家的支持。
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