MySQL 判断和删除目录和表外键

--
-- Procedure Of Delete Index
--
DROP PROCEDURE IF EXISTS DEL_IDX;
CREATE PROCEDURE DEL_IDX(IN P_TABLE_NAME varchar(200), IN P_IDX_NAME VARCHAR(200))
BEGIN
DECLARE ST VARCHAR(250);
  SET @ST=CONCAT(' DROP INDEX ', P_IDX_NAME, ' ON ', P_TABLE_NAME);
  SELECT count(*) INTO @CNT FROM information_schema.statistics WHERE table_name=P_TABLE_NAME and index_name=P_IDX_NAME;
  IF @CNT >0 THEN
    PREPARE stmt FROM @ST;
    EXECUTE stmt;
  END IF;
END;
CALL DEL_IDX('T_NAME, 'IDX_NAME');
DROP PROCEDURE IF EXISTS DEL_IDX;

--
-- Procedure Of Delete FK
--
DROP PROCEDURE IF EXISTS DEL_FK;
CREATE PROCEDURE DEL_FK(IN P_TABLE_NAME varchar(200), IN F_K_NAME VARCHAR(200))
BEGIN
DECLARE ST VARCHAR(250);
  SET @ST=CONCAT(' ALTER TABLE ', P_TABLE_NAME, ' DROP FOREIGN KEY ', F_K_NAME);
  SELECT COUNT(*) INTO @CNT FROM information_schema.key_column_usage WHERE table_name=P_TABLE_NAME and constraint_name=F_K_NAME;
  IF @CNT >0 THEN
    PREPARE stmt FROM @ST;
    EXECUTE stmt;
  END IF;
END;
CALL DEL_FK('T_NAM, 'FK_NAME);
DROP PROCEDURE IF EXISTS DEL_FK;