MySQL批量生成主键、外键的SQL语句


首先咱们须要查询列的信息,这须要用到[INFORMATION_SCHEMA].[COLUMNS]系统视图来查询数据列的信息,SQL 以下:数据

复制代码代码以下:查询


SELECT  c.TABLE_SCHEMA ,
        c.TABLE_NAME ,
        c.COLUMN_NAME ,
        c.DATA_TYPE ,
        c.CHARACTER_MAXIMUM_LENGTH ,
        c.COLUMN_DEFAULT ,
        c.IS_NULLABLE ,
        c.NUMERIC_PRECISION ,
        c.NUMERIC_SCALE
FROM    [INFORMATION_SCHEMA].[COLUMNS] c
WHERE   TABLE_NAME = 'Address'系统


运行结果以下:

咱们都知道咱们在定义列的时候通常的使用都是varchar(50)之类的信息,这里咱们须要整合DATA_TYPE和CHARACTER_MAXIMUM_LENGTH信息,当CHARACTER_MAXIMUM_LENGTH为-1时即便说没有指定具体最大长度,数据的指定长度信息是max,而numeric须要整合NUMERIC_PRECISION、NUMERIC_SCALE信息。修改后的SQL以下:arc

复制代码代码以下:


SELECT  c.TABLE_SCHEMA ,
        c.TABLE_NAME ,
        c.COLUMN_NAME ,
        CASE WHEN ( ( CHARINDEX('char', c.DATA_TYPE) > 0
                      OR CHARINDEX('binary', c.DATA_TYPE) > 0
                    )
                    AND c.CHARACTER_MAXIMUM_LENGTH <> -1
                  )
             THEN c.DATA_TYPE + '('
                  + CAST(c.CHARACTER_MAXIMUM_LENGTH AS VARCHAR(4)) + ')'
             WHEN ( ( CHARINDEX('CHAR', c.DATA_TYPE) > 0
                      OR CHARINDEX('binary', c.DATA_TYPE) > 0
                    )
                    AND c.CHARACTER_MAXIMUM_LENGTH = -1
                  ) THEN c.DATA_TYPE + '(max)'
             WHEN ( CHARINDEX('numeric', c.DATA_TYPE) > 0 )
             THEN c.DATA_TYPE + '(' + CAST(c.NUMERIC_PRECISION AS VARCHAR(4))
                  + ',' + CAST(c.NUMERIC_SCALE AS VARCHAR(4)) + ')'
             ELSE c.DATA_TYPE
        END AS DATA_TYPE ,
        c.COLUMN_DEFAULT ,
        c.IS_NULLABLE ,
        c.COLUMN_DEFAULT
FROM    [INFORMATION_SCHEMA].[COLUMNS] c
WHERE   TABLE_NAME = 'Address'
ORDER BY c.ORDINAL_POSITION


运行结果如图:



如今咱们须要标记这张表的那些列是主键,那些列是外键,要查询表的主、外键信息须要用到[INFORMATION_SCHEMA].[TABLE_CONSTRAINTS]和[INFORMATION_SCHEMA].[KEY_COLUMN_USAGE] 系统视图
运行结果如图:

修改咱们先前的SQL语句:

复制代码代码以下:


SELECT  c.TABLE_SCHEMA ,
        c.TABLE_NAME ,
        c.COLUMN_NAME ,
        CASE WHEN ( ( CHARINDEX('char', c.DATA_TYPE) > 0
                      OR CHARINDEX('binary', c.DATA_TYPE) > 0
                    )
                    AND c.CHARACTER_MAXIMUM_LENGTH <> -1
                  )
             THEN c.DATA_TYPE + '('
                  + CAST(c.CHARACTER_MAXIMUM_LENGTH AS VARCHAR(4)) + ')'
             WHEN ( ( CHARINDEX('CHAR', c.DATA_TYPE) > 0
                      OR CHARINDEX('binary', c.DATA_TYPE) > 0
                    )
                    AND c.CHARACTER_MAXIMUM_LENGTH = -1
                  ) THEN c.DATA_TYPE + '(max)'
             WHEN ( CHARINDEX('numeric', c.DATA_TYPE) > 0 )
             THEN c.DATA_TYPE + '(' + CAST(c.NUMERIC_PRECISION AS VARCHAR(4))
                  + ',' + CAST(c.NUMERIC_SCALE AS VARCHAR(4)) + ')'
             ELSE c.DATA_TYPE
        END AS DATA_TYPE ,
        c.COLUMN_DEFAULT ,
        c.IS_NULLABLE ,
        c.COLUMN_DEFAULT ,
        CASE WHEN tc.CONSTRAINT_TYPE = 'PRIMARY KEY' THEN 'YES'
             ELSE 'NO'
        END AS IS_PRIMARY_KEY ,
        CASE WHEN tc.CONSTRAINT_TYPE = 'FOREIGN KEY' THEN 'YES'
             ELSE 'NO'
        END AS IS_FOREIGN_KEY
FROM    [INFORMATION_SCHEMA].[COLUMNS] c
        LEFT JOIN [INFORMATION_SCHEMA].[KEY_COLUMN_USAGE] kcu ON kcu.TABLE_SCHEMA = c.TABLE_SCHEMA
                                                              AND kcu.TABLE_NAME = c.TABLE_NAME
                                                              AND kcu.COLUMN_NAME = c.COLUMN_NAME
        LEFT JOIN [INFORMATION_SCHEMA].[TABLE_CONSTRAINTS] tc ON tc.CONSTRAINT_SCHEMA = kcu.CONSTRAINT_SCHEMA
                                                              AND tc.CONSTRAINT_NAME = kcu.CONSTRAINT_NAME
WHERE   c.TABLE_NAME = 'Address'
ORDER BY c.ORDINAL_POSITION


运行结果如图:

如今咱们已经知道那些列是主键那些是外键,接下来的就是外键列所关联的外检表信息,这里须要用到[INFORMATION_SCHEMA].[REFERENTIAL_CONSTRAINTS]系统视图,运行该视图以下:

因此修改咱们的SQL以下:

复制代码代码以下:


SELECT  c.TABLE_SCHEMA ,
        c.TABLE_NAME ,
        c.COLUMN_NAME ,
        CASE WHEN ( ( CHARINDEX('char', c.DATA_TYPE) > 0
                      OR CHARINDEX('binary', c.DATA_TYPE) > 0
                    )
                    AND c.CHARACTER_MAXIMUM_LENGTH <> -1
                  )
             THEN c.DATA_TYPE + '('
                  + CAST(c.CHARACTER_MAXIMUM_LENGTH AS VARCHAR(4)) + ')'
             WHEN ( ( CHARINDEX('CHAR', c.DATA_TYPE) > 0
                      OR CHARINDEX('binary', c.DATA_TYPE) > 0
                    )
                    AND c.CHARACTER_MAXIMUM_LENGTH = -1
                  ) THEN c.DATA_TYPE + '(max)'
             WHEN ( CHARINDEX('numeric', c.DATA_TYPE) > 0 )
             THEN c.DATA_TYPE + '(' + CAST(c.NUMERIC_PRECISION AS VARCHAR(4))
                  + ',' + CAST(c.NUMERIC_SCALE AS VARCHAR(4)) + ')'
             ELSE c.DATA_TYPE
        END AS DATA_TYPE ,
        c.COLUMN_DEFAULT ,
        c.IS_NULLABLE ,
        c.COLUMN_DEFAULT ,
        CASE WHEN tc.CONSTRAINT_TYPE = 'PRIMARY KEY' THEN 'YES'
             ELSE 'NO'
        END AS IS_PRIMARY_KEY ,
        CASE WHEN tc.CONSTRAINT_TYPE = 'FOREIGN KEY' THEN 'YES'
             ELSE 'NO'
        END AS IS_FOREIGN_KEY,
        fkcu.COLUMN_NAME AS FOREIGN_KEY,
        fkcu.TABLE_NAME AS FOREIGN_TABLE
FROM    [INFORMATION_SCHEMA].[COLUMNS] c
        LEFT JOIN [INFORMATION_SCHEMA].[KEY_COLUMN_USAGE] kcu ON kcu.TABLE_SCHEMA = c.TABLE_SCHEMA
                                                              AND kcu.TABLE_NAME = c.TABLE_NAME
                                                              AND kcu.COLUMN_NAME = c.COLUMN_NAME
        LEFT JOIN [INFORMATION_SCHEMA].[TABLE_CONSTRAINTS] tc ON tc.CONSTRAINT_SCHEMA = kcu.CONSTRAINT_SCHEMA
                                                              AND tc.CONSTRAINT_NAME = kcu.CONSTRAINT_NAME
        LEFT JOIN [INFORMATION_SCHEMA].[REFERENTIAL_CONSTRAINTS] fc ON kcu.CONSTRAINT_SCHEMA = fc.CONSTRAINT_SCHEMA
                                                              AND kcu.CONSTRAINT_NAME = fc.CONSTRAINT_NAME
        LEFT JOIN [INFORMATION_SCHEMA].[KEY_COLUMN_USAGE] fkcu ON fkcu.CONSTRAINT_SCHEMA = fc.UNIQUE_CONSTRAINT_SCHEMA
                                                              AND fkcu.CONSTRAINT_NAME = fc.UNIQUE_CONSTRAINT_NAME
WHERE   c.TABLE_NAME = 'Address'
ORDER BY c.ORDINAL_POSITION


运行结果如图:

咱们的查询结果中显示了太多的NULL,看着不怎么舒服,还有咱们的表名应该显示一次就能够,修改SQL以下:

复制代码代码以下:


SELECT  CASE WHEN c.ORDINAL_POSITION = 1
             THEN c.TABLE_SCHEMA + '.' + c.TABLE_NAME
             ELSE ''
        END AS TABLE_NAME ,
        c.COLUMN_NAME ,
        CASE WHEN ( ( CHARINDEX('char', c.DATA_TYPE) > 0
                      OR CHARINDEX('binary', c.DATA_TYPE) > 0
                    )
                    AND c.CHARACTER_MAXIMUM_LENGTH <> -1
                  )
             THEN c.DATA_TYPE + '('
                  + CAST(c.CHARACTER_MAXIMUM_LENGTH AS VARCHAR(4)) + ')'
             WHEN ( ( CHARINDEX('CHAR', c.DATA_TYPE) > 0
                      OR CHARINDEX('binary', c.DATA_TYPE) > 0
                    )
                    AND c.CHARACTER_MAXIMUM_LENGTH = -1
                  ) THEN c.DATA_TYPE + '(max)'
             WHEN ( CHARINDEX('numeric', c.DATA_TYPE) > 0 )
             THEN c.DATA_TYPE + '(' + CAST(c.NUMERIC_PRECISION AS VARCHAR(4))
                  + ',' + CAST(c.NUMERIC_SCALE AS VARCHAR(4)) + ')'
             ELSE c.DATA_TYPE
        END AS DATA_TYPE ,
        ISNULL(c.COLUMN_DEFAULT, '') AS COLUMN_DEFAULT ,
        CASE WHEN c.IS_NULLABLE = 'YES' THEN '√'
             ELSE ''
        END IS_NULLABLE ,
        CASE WHEN tc.CONSTRAINT_TYPE = 'PRIMARY KEY' THEN '√'
             ELSE ''
        END AS IS_PRIMARY_KEY ,
        CASE WHEN tc.CONSTRAINT_TYPE = 'FOREIGN KEY' THEN '√'
             ELSE ''
        END AS IS_FOREIGN_KEY ,
        ISNULL(fkcu.COLUMN_NAME, '') AS FOREIGN_KEY ,
        ISNULL(fkcu.TABLE_NAME, '') AS FOREIGN_TABLE
FROM    [INFORMATION_SCHEMA].[COLUMNS] c
        LEFT JOIN [INFORMATION_SCHEMA].[KEY_COLUMN_USAGE] kcu ON kcu.TABLE_SCHEMA = c.TABLE_SCHEMA
                                                              AND kcu.TABLE_NAME = c.TABLE_NAME
                                                              AND kcu.COLUMN_NAME = c.COLUMN_NAME
        LEFT JOIN [INFORMATION_SCHEMA].[TABLE_CONSTRAINTS] tc ON tc.CONSTRAINT_SCHEMA = kcu.CONSTRAINT_SCHEMA
                                                              AND tc.CONSTRAINT_NAME = kcu.CONSTRAINT_NAME
        LEFT JOIN [INFORMATION_SCHEMA].[REFERENTIAL_CONSTRAINTS] fc ON kcu.CONSTRAINT_SCHEMA = fc.CONSTRAINT_SCHEMA
                                                              AND kcu.CONSTRAINT_NAME = fc.CONSTRAINT_NAME
        LEFT JOIN [INFORMATION_SCHEMA].[KEY_COLUMN_USAGE] fkcu ON fkcu.CONSTRAINT_SCHEMA = fc.UNIQUE_CONSTRAINT_SCHEMA
                                                              AND fkcu.CONSTRAINT_NAME = fc.UNIQUE_CONSTRAINT_NAME
WHERE   c.TABLE_NAME = 'Address'
ORDER BY c.ORDINAL_POSITION

运行结果如图: 有不对的地方还请你们拍砖!