MySQL variables in ALTER TABLE script
Hello The following procedure will have to move all constraints from one table to the other however I am having some difficulties at the point where the constraint should be deleted.

The problem: how do I use variables in the following line 

    ALTER TABLE var_referenced_table_name DROP FOREIGN KEY var_constraint_name;

when I use as is, I receive the following error

    Error Code: 1146. Table 'oaf_businesslink_dev.var_referenced_table_name' doesn't exist

MySQL does not recognise `var_referenced_table_name` and `var_constraint_name` as variables.

    DELIMITER //
    DROP PROCEDURE IF EXISTS AlterConstraints//
    CREATE PROCEDURE AlterConstraints()
    BEGIN
    
        DECLARE schema_name VARCHAR(60) DEFAULT 'oaf_businesslink_dev';
        DECLARE table_name VARCHAR(60) DEFAULT 'wp_systemuser';
    
        DECLARE finished INTEGER DEFAULT 0;
        DECLARE total INTEGER DEFAULT 0;    
        
        DECLARE var_constraint_name VARCHAR(60) DEFAULT '';
        DECLARE var_table_name VARCHAR(60) DEFAULT '';
        DECLARE var_column_name VARCHAR(60) DEFAULT '';
        DECLARE var_referenced_table_name VARCHAR(60) DEFAULT '';
        DECLARE var_referenced_column_name VARCHAR(60) DEFAULT '';
        
        DECLARE cur_constraints CURSOR FOR SELECT constraint_Name, table_name,column_name,referenced_table_name,referenced_column_name
        FROM information_schema.key_column_usage
        WHERE constraint_schema = schema_name
            AND referenced_table_name = table_name
            AND table_name IS NOT NULL;
        
        DECLARE CONTINUE HANDLER FOR NOT FOUND SET finished = 1;
        OPEN cur_constraints;
        
        get_constraint: 
        LOOP FETCH cur_constraints 
        INTO var_constraint_name
            ,var_table_name
            ,var_column_name
            ,var_referenced_table_name
            ,var_referenced_column_name;          
    
            IF finished THEN
                LEAVE get_constraint;
            END IF; 
            
            /* Get Constraint Count */
            SET total = total + 1;
            
            /* Remove Constraint */
            IF EXISTS(SELECT * FROM information_schema.TABLE_CONSTRAINTS
                WHERE CONSTRAINT_NAME = var_constraint_name AND TABLE_NAME = var_referenced_table_name AND TABLE_SCHEMA = schema_name)
                THEN
                /* 
                 * Error Code: 1146. Table 'oaf_businesslink_dev.var_referenced_table_name' doesn't exist
                 */
                ALTER TABLE var_referenced_table_name DROP FOREIGN KEY var_constraint_name;
            END IF;
            
            /* Change Datatype to BIGINT */
            
            /* Recreate Constraint to new table */
        END
        
        LOOP get_constraint;
        CLOSE cur_constraints;
        SELECT total;
        
    END
    //
    DELIMITER ;
    
    CALL AlterConstraints();

Thanks in advance.
MySQL variables in ALTER TABLE script
===

Hello The following procedure will have to move all constraints from one table to the other however I am having some difficulties at the point where the constraint should be deleted.

The problem: how do I use variables in the following line 

    ALTER TABLE var_referenced_table_name DROP FOREIGN KEY var_constraint_name;

when I use as is, I receive the following error

    Error Code: 1146. Table 'oaf_businesslink_dev.var_referenced_table_name' doesn't exist

MySQL does not recognise `var_referenced_table_name` and `var_constraint_name` as variables.

    DELIMITER //
    DROP PROCEDURE IF EXISTS AlterConstraints//
    CREATE PROCEDURE AlterConstraints()
    BEGIN
    
        DECLARE schema_name VARCHAR(60) DEFAULT 'oaf_businesslink_dev';
        DECLARE table_name VARCHAR(60) DEFAULT 'wp_systemuser';
    
        DECLARE finished INTEGER DEFAULT 0;
        DECLARE total INTEGER DEFAULT 0;    
        
        DECLARE var_constraint_name VARCHAR(60) DEFAULT '';
        DECLARE var_table_name VARCHAR(60) DEFAULT '';
        DECLARE var_column_name VARCHAR(60) DEFAULT '';
        DECLARE var_referenced_table_name VARCHAR(60) DEFAULT '';
        DECLARE var_referenced_column_name VARCHAR(60) DEFAULT '';
        
        DECLARE cur_constraints CURSOR FOR SELECT constraint_Name, table_name,column_name,referenced_table_name,referenced_column_name
        FROM information_schema.key_column_usage
        WHERE constraint_schema = schema_name
            AND referenced_table_name = table_name
            AND table_name IS NOT NULL;
        
        DECLARE CONTINUE HANDLER FOR NOT FOUND SET finished = 1;
        OPEN cur_constraints;
        
        get_constraint: 
        LOOP FETCH cur_constraints 
        INTO var_constraint_name
            ,var_table_name
            ,var_column_name
            ,var_referenced_table_name
            ,var_referenced_column_name;          
    
            IF finished THEN
                LEAVE get_constraint;
            END IF; 
            
            /* Get Constraint Count */
            SET total = total + 1;
            
            /* Remove Constraint */
            IF EXISTS(SELECT * FROM information_schema.TABLE_CONSTRAINTS
                WHERE CONSTRAINT_NAME = var_constraint_name AND TABLE_NAME = var_referenced_table_name AND TABLE_SCHEMA = schema_name)
                THEN
                /* 
                 * Error Code: 1146. Table 'oaf_businesslink_dev.var_referenced_table_name' doesn't exist
                 */
                ALTER TABLE var_referenced_table_name DROP FOREIGN KEY var_constraint_name;
            END IF;
            
            /* Change Datatype to BIGINT */
            
            /* Recreate Constraint to new table */
        END
        
        LOOP get_constraint;
        CLOSE cur_constraints;
        SELECT total;
        
    END
    //
    DELIMITER ;
    
    CALL AlterConstraints();

Thanks in advance.