Can Foreign Key Verification be Enforced in InnoDB?

Can Foreign Key Verification be Enforced in InnoDB?

Maintaining data integrity in InnoDB tables with foreign key constraints can be challenging. Turning foreign key checks off during data updates can compromise referential integrity, making it essential to recheck constraints after the updates are complete.

Unfortunately, MySQL provides no direct mechanism to force InnoDB to recheck foreign key constraints for specific tables or a database. However, the following stored procedure can be used as a workaround:

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, '`', ') ', 

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