如何方便的维护postgresql中的数据字典？

1.场景描述

在日常的数据开发过程中，如果是任务紧急，或者是任务量大的时候，我们往往没有足够的时间来专程进行数据字典的维护。但数据字典无论是对于维护数据资产，还是推动企业的数字化转型来说，都有着非凡的意义。
在数据开发过程中，我们可以采用先将任务完成后，对逐个表进行注释，待注释完成后，结合本文中的SQL语句即可方便的构建数据字典。

2.实现方法

2.1 获取某schema下的所有表名称及注释

SELECT
	tb.TABLE_NAME,
	d.description 
FROM
	information_schema.tables tb
	JOIN pg_class C ON C.relname = tb.
	TABLE_NAME LEFT JOIN pg_description d ON d.objoid = C.oid 
	AND d.objsubid = '0' 
WHERE
	tb.table_schema = 'test';

2.2 查询某schema所有表名称及注释

-- 查询某schema所有表名称及注释
SELECT C
	.relname 表名,
	A.attname 字段名,
	CAST ( obj_description ( relfilenode, 'pg_class' ) AS VARCHAR ) 字段描述,
	concat_ws ( '', T.typname, SUBSTRING ( format_type ( A.atttypid, A.atttypmod ) FROM '\(.*\)' ) ) AS 字段类型 ,
	d.description 字段备注 
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 IN ( 'ads' ) AND POSITION ( '_2' IN tablename ) = 0 AND relname LIKE'%ads_scm%' ) 
ORDER BY
	C.relname,
	A.attnum;

-- 查询所有列注释,有列序号
SELECT
	col.TABLE_NAME,
	col.COLUMN_NAME,
	col.ordinal_position AS o,
	d.description 
FROM
	information_schema.COLUMNS col
	JOIN pg_class C ON C.relname = col.
	TABLE_NAME LEFT JOIN pg_description d ON d.objoid = C.oid 
	AND d.objsubid = col.ordinal_position 
WHERE
	col.table_schema = 'test' 
ORDER BY
	col.TABLE_NAME,
	col.ordinal_position;

2.3 查询schema下所有没注释的表

-- 查询schema下所有没注释的表
SELECT
	tb.TABLE_NAME,
	d.description 
FROM
	information_schema.tables tb
	JOIN pg_class C ON C.relname = tb.
	TABLE_NAME LEFT JOIN pg_description d ON d.objoid = C.oid 
	AND d.objsubid = '0' 
WHERE
	tb.table_schema = 'test' 
	AND d.description IS NULL;

2.4 查询某schema下所有没注释的表名及列名

-- 查询某schema下所有没注释的表名及列名
SELECT
	col.TABLE_NAME,
	col.COLUMN_NAME,
	col.ordinal_position AS o,
	d.description 
FROM
	information_schema.COLUMNS col
	JOIN pg_class C ON C.relname = col.
	TABLE_NAME LEFT JOIN pg_description d ON d.objoid = C.oid 
	AND d.objsubid = col.ordinal_position 
WHERE
	col.table_schema in ('test') 
	AND description IS NULL 
ORDER BY
	col.TABLE_NAME,
	col.ordinal_position;

3.文章总结

对于数据库的维护来说，数据字典是不可获取的一部分。希望本篇文章能帮助到更多人~