By using this site, you agree to our updated Privacy Policy and our Terms of Use. Manage your Cookies Settings.
424,949 Members | 1,086 Online
Bytes IT Community
+ Ask a Question
Need help? Post your question and get tips & solutions from a community of 424,949 IT Pros & Developers. It's quick & easy.

HELP! Synchronize db and maintain foreign key relations?

P: 2
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...local is ms sql..

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.
Jan 30 '07 #1
Share this Question
Share on Google+
1 Reply


PEB
Expert 100+
P: 1,418
PEB
Hi,

The way i'm using is to create my own table with two columns...

The columns are Old_ID and New_ID

Before syncronization u inserts all elements from the synchronized table there!

After appending ur data into the main table u need to identify using other field /s/ which id corresponds to ur ancient id /with Update action query

The last step is appending the info from the table with foreign keys linked with ur temporary table. Instaed using the old foreign key u need to put the new entry and the information will be at its place!

Hope this helps as conception!

:)
Jan 31 '07 #2

Post your reply

Sign in to post your reply or Sign up for a free account.