我有一组InnoDB个表，我需要定期删除一些行并插入其他行来维护它们.其中几个表具有引用其他表的外键约束，因此这意味着表加载顺序很重要.为了插入新行而不必担心表的顺序，我使用:
SET FOREIGN_KEY_CHECKS=0;
之前，然后:
SET FOREIGN_KEY_CHECKS=1;
之后
加载完成后，我想判断更新表中的数据是否仍然保持引用完整性——新行没有打破外键约束——但似乎没有办法做到这一点.
作为测试，我输入了我确定违反外键约束的数据，在重新启用外键判断后，mysql没有产生任何警告或错误.
如果我试图找到一种方法来指定表的加载顺序，并在加载过程中保持外键判断处于打开状态，这将不允许我在具有自引用外键约束的表中加载数据，因此这不是一个可接受的解决方案.
有没有办法强迫InnoDB验证表或数据库的外键约束？
DELIMITER $$
DROP PROCEDURE IF EXISTS ANALYZE_INVALID_FOREIGN_KEYS$$
CREATE
PROCEDURE `ANALYZE_INVALID_FOREIGN_KEYS`(
checked_database_name VARCHAR(64),
checked_table_name VARCHAR(64),
temporary_result_table ENUM('Y', 'N'))
LANGUAGE SQL
NOT DETERMINISTIC
READS SQL DATA
BEGIN
DECLARE TABLE_SCHEMA_VAR VARCHAR(64);
DECLARE TABLE_NAME_VAR VARCHAR(64);
DECLARE COLUMN_NAME_VAR VARCHAR(64);
DECLARE CONSTRAINT_NAME_VAR VARCHAR(64);
DECLARE REFERENCED_TABLE_SCHEMA_VAR VARCHAR(64);
DECLARE REFERENCED_TABLE_NAME_VAR VARCHAR(64);
DECLARE REFERENCED_COLUMN_NAME_VAR VARCHAR(64);
DECLARE KEYS_SQL_VAR VARCHAR(1024);
DECLARE done INT DEFAULT 0;
DECLARE foreign_key_cursor CURSOR FOR
SELECT
`TABLE_SCHEMA`,
`TABLE_NAME`,
`COLUMN_NAME`,
`CONSTRAINT_NAME`,
`REFERENCED_TABLE_SCHEMA`,
`REFERENCED_TABLE_NAME`,
`REFERENCED_COLUMN_NAME`
FROM
information_schema.KEY_COLUMN_USAGE
WHERE
`CONSTRAINT_SCHEMA` LIKE checked_database_name AND
`TABLE_NAME` LIKE checked_table_name AND
`REFERENCED_TABLE_SCHEMA` IS NOT NULL;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
IF temporary_result_table = 'N' THEN
DROP TEMPORARY TABLE IF EXISTS INVALID_FOREIGN_KEYS;
DROP TABLE IF EXISTS INVALID_FOREIGN_KEYS;
CREATE TABLE INVALID_FOREIGN_KEYS(
`TABLE_SCHEMA` VARCHAR(64),
`TABLE_NAME` VARCHAR(64),
`COLUMN_NAME` VARCHAR(64),
`CONSTRAINT_NAME` VARCHAR(64),
`REFERENCED_TABLE_SCHEMA` VARCHAR(64),
`REFERENCED_TABLE_NAME` VARCHAR(64),
`REFERENCED_COLUMN_NAME` VARCHAR(64),
`INVALID_KEY_COUNT` INT,
`INVALID_KEY_SQL` VARCHAR(1024)
);
ELSEIF temporary_result_table = 'Y' THEN
DROP TEMPORARY TABLE IF EXISTS INVALID_FOREIGN_KEYS;
DROP TABLE IF EXISTS INVALID_FOREIGN_KEYS;
CREATE TEMPORARY TABLE INVALID_FOREIGN_KEYS(
`TABLE_SCHEMA` VARCHAR(64),
`TABLE_NAME` VARCHAR(64),
`COLUMN_NAME` VARCHAR(64),
`CONSTRAINT_NAME` VARCHAR(64),
`REFERENCED_TABLE_SCHEMA` VARCHAR(64),
`REFERENCED_TABLE_NAME` VARCHAR(64),
`REFERENCED_COLUMN_NAME` VARCHAR(64),
`INVALID_KEY_COUNT` INT,
`INVALID_KEY_SQL` VARCHAR(1024)
);
END IF;
OPEN foreign_key_cursor;
foreign_key_cursor_loop: LOOP
FETCH foreign_key_cursor INTO
TABLE_SCHEMA_VAR,
TABLE_NAME_VAR,
COLUMN_NAME_VAR,
CONSTRAINT_NAME_VAR,
REFERENCED_TABLE_SCHEMA_VAR,
REFERENCED_TABLE_NAME_VAR,
REFERENCED_COLUMN_NAME_VAR;
IF done THEN
LEAVE foreign_key_cursor_loop;
END IF;
SET @from_part = CONCAT('FROM ', '`', TABLE_SCHEMA_VAR, '`.`', TABLE_NAME_VAR, '`', ' AS REFERRING ',
'LEFT JOIN `', REFERENCED_TABLE_SCHEMA_VAR, '`.`', REFERENCED_TABLE_NAME_VAR, '`', ' AS REFERRED ',
'ON (REFERRING', '.`', COLUMN_NAME_VAR, '`', ' = ', 'REFERRED', '.`', REFERENCED_COLUMN_NAME_VAR, '`', ') ',
'WHERE REFERRING', '.`', COLUMN_NAME_VAR, '`', ' IS NOT NULL ',
'AND REFERRED', '.`', REFERENCED_COLUMN_NAME_VAR, '`', ' IS NULL');
SET @full_query = CONCAT('SELECT COUNT(*) ', @from_part, ' INTO @invalid_key_count;');
PREPARE stmt FROM @full_query;
EXECUTE stmt;
IF @invalid_key_count > 0 THEN
INSERT INTO
INVALID_FOREIGN_KEYS
SET
`TABLE_SCHEMA` = TABLE_SCHEMA_VAR,
`TABLE_NAME` = TABLE_NAME_VAR,
`COLUMN_NAME` = COLUMN_NAME_VAR,
`CONSTRAINT_NAME` = CONSTRAINT_NAME_VAR,
`REFERENCED_TABLE_SCHEMA` = REFERENCED_TABLE_SCHEMA_VAR,
`REFERENCED_TABLE_NAME` = REFERENCED_TABLE_NAME_VAR,
`REFERENCED_COLUMN_NAME` = REFERENCED_COLUMN_NAME_VAR,
`INVALID_KEY_COUNT` = @invalid_key_count,
`INVALID_KEY_SQL` = CONCAT('SELECT ',
'REFERRING.', '`', COLUMN_NAME_VAR, '` ', 'AS "Invalid: ', COLUMN_NAME_VAR, '", ',
'REFERRING.* ',
@from_part, ';');
END IF;
DEALLOCATE PREPARE stmt;
END LOOP foreign_key_cursor_loop;
END$$
DELIMITER ;
CALL ANALYZE_INVALID_FOREIGN_KEYS('%', '%', 'Y');
DROP PROCEDURE IF EXISTS ANALYZE_INVALID_FOREIGN_KEYS;
SELECT * FROM INVALID_FOREIGN_KEYS;
可以使用此存储过程判断all数据库中是否存在无效的外键.
结果是否是暂时的.它可以是:'Y''N'NULL.
'Y'，ANALYZE_INVALID_FOREIGN_KEYS结果表将是临时表.'N'，然后从另一个会话执行SELECT * FROM INVALID_FOREIGN_KEYS;.必须使用NULL来跳过事务中的结果表创建，因为MySQL在CREATE TABLE ...和DROP TABLE ...的事务中执行隐式提交，所以创建结果表会导致事务中出现问题.在这种情况下，您必须自己从BEGIN; COMMIT/ROLLBACK;块中创建结果表:
CREATE TABLE INVALID_FOREIGN_KEYS(
`TABLE_SCHEMA` VARCHAR(64),
`TABLE_NAME` VARCHAR(64),
`COLUMN_NAME` VARCHAR(64),
`CONSTRAINT_NAME` VARCHAR(64),
`REFERENCED_TABLE_SCHEMA` VARCHAR(64),
`REFERENCED_TABLE_NAME` VARCHAR(64),
`REFERENCED_COLUMN_NAME` VARCHAR(64),
`INVALID_KEY_COUNT` INT,
`INVALID_KEY_SQL` VARCHAR(1024)
);
访问MySQL网站了解隐式提交:http://dev.mysql.com/doc/refman/5.6/en/implicit-commit.html
这INVALID_FOREIGN_KEYS行将只包含无效数据库、表和列的名称.但是，如果存在无效引用行，则可以看到执行值为INVALID_KEY_SQL列或INVALID_FOREIGN_KEYS列的无效引用行.
如果引用列(又名foreign index)和引用列(通常是主键)上都有索引，那么这个存储过程将非常快.