Mysql数据字典

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1 关于约束的数据字典

mysql> select DISTINCT a.CONSTRAINT_TYPE from information_schema.table_constraints a;

mysql> select * from information_schema.table_constraints a where CONSTRAINT_SCHEMA='db1';

2 查询表和列

--最齐全的信息查询
SELECT a.TABLE_NAME "表",
a.COLUMN_NAME "列",
a.COLUMN_TYPE "类型",
a.COLUMN_DEFAULT "默认值",
a.IS_NULLABLE "是否为空",
a.CHARACTER_SET_NAME "表字符集",
a.COLLATION_NAME "校验字符集",
CONCAT_WS(',',a.COLUMN_COMMENT,a.COLUMN_KEY, a.EXTRA) "列备注",
b.TABLE_COMMENT "表备注" ,
b.ENGINE "引擎"
FROM information_schema.COLUMNS a,information_schema.TABLES b
WHERE a.TABLE_SCHEMA=b.TABLE_SCHEMA
AND a.TABLE_SCHEMA='db1'
AND a.TABLE_NAME=b.TABLE_NAME
order by a.ORDINAL_POSITION;

3 查询索引信息

SELECT
TABLE_SCHEMA,
TABLE_NAME,
NON_UNIQUE,
INDEX_NAME,
SEQ_IN_INDEX,
COLUMN_NAME,
INDEX_TYPE,
CONCAT(COMMENT,INDEX_COMMENT) INDEX_COMMENT
FROM INFORMATION_SCHEMA.STATISTICS
WHERE TABLE_SCHEMA = 'db1'
ORDER BY TABLE_SCHEMA,TABLE_NAME,INDEX_NAME,SEQ_IN_INDEX;