MySQL Create table with reference to non existant table - mysql

Question

Using MySQL workbench, I copied the create statement from a few related tables to put into a clean schema. They all reference each other in some way so there is no inherent order I can create them in. How can I just force MySQL to create the tables while ignoring any warning that may occur, just until the rest of the tables are created?
Would I have to group it inside a transaction of some sort?
A very simple example would be:
CREATE TABLE `vehicle` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`gallery_id` int(11) DEFAULT NULL,
`make_id` int(11) NOT NULL,
`model_id` int(11) DEFAULT NULL,
`make` varchar(100) DEFAULT '',
`model` varchar(100) DEFAULT '',
`colour_id` int(11) DEFAULT NULL,
`currency_id` int(11) NOT NULL DEFAULT '1',
`fuel_id` int(11) DEFAULT NULL,
`status_id` int(11) DEFAULT NULL,
`stock_code` varchar(100) DEFAULT NULL,
`registration` varchar(20) DEFAULT NULL,
`title` varchar(100) DEFAULT NULL,
`description` text,
`month` tinyint(4) DEFAULT NULL,
`public` tinyint(4) NOT NULL DEFAULT '0',
`sold` tinyint(4) NOT NULL DEFAULT '0',
PRIMARY KEY (`id`),
KEY `vehicle_fk_idx` (`status_id`),
CONSTRAINT `vehicle_fk` FOREIGN KEY (`status_id`) REFERENCES `vehicle_status` (`id`) ON DELETE SET NULL ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
CREATE TABLE `vehicle_status` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`slug` varchar(100) DEFAULT NULL,
`title` varchar(100) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `slug_UNIQUE` (`slug`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1;
vehicle references vehicle_status which would mean that vehicle_status would have to be created first. How would I create vehicle first and then vehicle_status without adding the reference afterwards?

Answer 1

You do not define foreign keys when creating tables, you would have them in a separate query like this:
ALTER TABLE `vehicle`
ADD CONSTRAINT `vehicle_ibfk_1` FOREIGN KEY (`status_id`)
REFERENCES `vehicle_status` (`id`) ON DELETE SET NULL ON UPDATE CASCADE;
So you would first create tables and then create foreign keys.
The way I personally do is I have all CREATE TABLE queries in one file that I know I can simply just import without any errors. I have all CONSTRAINT queries in a separate file that I import after all the tables have been created and I have all INSERT INTO queries in a separate file that adds data after all constraints and tables have been set.

Answer 2

It looks like vehicle_status is a lookup table, while vehicle is a primary transaction table.
In general, lookup tables do not reference other tables, although there can be designs where one lookup table references another lookup table. In your case, it's simple: just create vehicle_status first. If your schema has a hundred tables in it, it's going to involve a little work to order the create commands in the right sequence.
There are designs where the reference chain forms a circle. In such a case, you'll have to do what GGio suggests: add the constraints later. There are other problems with designs involving circular references, and those problems may or may not be present in your schema.
When you go to populate the tables, you'll have to worry about order as well. In general, you'll have to populate the lookup tables first, before you begin to populate the transaction tables. Otherwise you'll get reference violations at load time.