具有两个不同名称的MYSQL表

Question

I am integrating two systems, moodle and zen-cart. Each system has its own table for storing user data. I need both systems to access the same table for customers. Moodle has a table called mdl_users. Zen-cart has a table called customers. The tables contain similar data but with different field names:

mdl_users fields:
id, username, password, firstname, lastname, email, etc....

customers fields:
customers_id, customers_nick, customers_password, customers_firstname, customers_lastname, customers_email_address, etc...

There are hundreds of queries in each system pointing at these tables (in a not well encapsalated way).

Is there a way to point one table at the other, meaning all calls to the customers table will be pulled from the mdl_users table (with field name relations specified)? I'm not looking to re-write all several hundred queries, but rather set something up once (or call it once per DB call) that automatically does this.

Hoped for example result:

This query (from the zen-cart system):

Select customers_password from customers where customers_id = :id

Actually returns the results as if it had run:

select password from mdl_user where id = :id

(edit/addition) mdl_users.id is the primary key field for the moodle system. (Unique, indexed, autonumbered). customers.customers_id is the same for the zen-cart system.

Any solution would have to maintain consistency of the primary key numbers as inserts and updates are made.

Answer 1

You can use Triggers to do that, search for sql triggers. This can make a call from one table to another, i mean you can program the trigger in order to recieve Moodle query and generate a query for zen-cart table.

Answer 2

Which is the "master" system? Are users added from both Zen Cart and Moodle, or only from one (or from a different source)?

I don't think there's a way to do this using only sql, though as suggested before, a view could be a partial solution. I don't see how you could make sure "inserts" work as they should, if only because of data that you could have in one system but not in the other.

Moodle provides a few ways in which it is possible to use an external system to synchronise users from : "external database authentication" is the first one that I can think of, but in this case, I would probably fork it (auth/db) to make a new plugin that would actually update Zen Cart's db with Moodle's new/updated users (if users can be added in Moodle).

I don't know enough about Zen Cart to suggest something on that side (though there doesn't seem to be any "user/auth plugins"), but it would be worth investigating.