No Need to Create Constraints?

[Lola Lee Beno]

I'm trying to create a database, using code generated by MySQL Workbench 
5.2.21 RC.  I'm running into this strange issue:

ERROR 1005 (HY000): Can't create table 'nxdb.#sql-a6_3b' (errno: 150)

Database was created using utf8 as charset, collation utf8_general_ci.

Original code generated by Workbench:

CREATE  TABLE IF NOT EXISTS `nxdb`.`User_Role` (
  `user_id` VARCHAR(35) NOT NULL ,
  `role_id` VARCHAR(35) NOT NULL ,
  PRIMARY KEY (`user_id`, `role_id`) ,
  CONSTRAINT `user_id`
    FOREIGN KEY (`user_id`)
    REFERENCES `nxdb`.`Users` (`user_id`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `role_id`
    FOREIGN KEY (`role_id`)
    REFERENCES `nxdb`.`NXRoles` (`role_id`)
    ON DELETE CASCADE
    ON UPDATE CASCADE)
ENGINE = InnoDB;

(Note, tables Users and NXRoles were already created).  This query 
didn't work.  So, I stripped down to the basics to get the table created:

CREATE TABLE IF NOT EXISTS `nxdb`.`User_Role` (
  `user_id` VARCHAR(35) NOT NULL ,
  `role_id` VARCHAR(35) NOT NULL ,
  PRIMARY KEY (`user_id`, `role_id`) )
ENGINE = InnoDB;

Then, I tried running this:

ALTER TABLE `User_Role` ADD
  CONSTRAINT `role_id`
    FOREIGN KEY (`role_id`)
    REFERENCES `NXRoles` (`role_id`)
    ON DELETE CASCADE
    ON UPDATE CASCADE;

And got this error message:  ERROR 1005 (HY000): Can't create table 
'nxdb.#sql-a6_3b' (errno: 150)

When I check the structure of User_Role in phpMyAdmin (couldn't see a 
way to do this in Workbench), this is what I'm seeing:

Action    Keyname    Type    Unique    Packed    Field    Cardinality    
Collation    Null    Comment
        PRIMARY    BTREE    Yes    No    user_id    0    A
                                         role_id    0    A


So, is there no need for me to actually add these constraints?

--
Lola J. Lee Beno
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