Unanswered: HELP! Synchronize db and maintain foriegn key relations?
I have to synchronize 2 databases hourly but am having difficulty maintaining foreign key relations. These tables use auto-increment columns as primary keys, with child records in other tables related with foreign keys. I can't change the way the local software uses primary or foreign keys as it is hardcoded in the local app. (microsoft retail management system)..(however the web-remote app is easily customized). I am using CDB synchronizer to sync the two databases because the remote one is mysql.
Example tables layout:
Items table has auto-increment primary key 'id'
TransactionEntry table has its own auto-increment primary key 'id' and a foreign key 'item_id'
Example of how remote and local database foreign key relations are incorrect after sync using CDB synchronizer:
8:00am -first installation of database-'item' tables auto-increment 'id' columns match with id last record value of '6'
locally the following products are added:
11001 short sleeve t---gets added with primary key in 'item' table 'id' of '7'
11002 long sleeve t----gets added with primary key in 'item' table 'id' '8'
remotely the following products are added:
21001 hipster jeans- --gets added with primary key in 'item' table 'id' of '7'
31001 overalls---gets added with primary key in 'item' table 'id' '8'
remotely someone orders 21001..so TransactionEntry table records sale of "item_id" of '7', but after synch with our local server,
product with "item_id" of '7' is "short sleeve t".
9:00 -synch takes place...item_id foreign key isn't accurate because of independent auto-increment values..
whenever a product is ordered, the TransactionEntry table will record the product's ID column thats available in it's own local copy... after synch, the 'item_id' field will not match the 'Item' table id field and the data about the transaction's product is lost.
I have read of solutions involving staging/temporary tables to cascade update foreign keys before synching into main database, but hopefully there is a more elegant solution for this. If this is only way, will it be reliable? foreign key mix-match seems like could cause havoc.