How to lock a set of tables??

Hi all,

Let's image I have a set of tables (for ex. 3 tables) which are logically connected with each other (i.e. every time I'm changing something in one table I necessarily will make some changes to other 2 tables).
Well, now I have two application - one is changing these tables (synchronising tables' content with application's environment) and another one which time by time reading these tables and makes some operations base on tables' content.
The problem is - if the first application started changes but not commited transaction yet and the second application running SELECT clause, then I could get a "wrong" data in the second app, i.e. content of some tables will be updated but content of other tables are old.
The ways to solve this... I think that it's possible to lock these tables before making changes in the first application and unlock tables after changes are complete. Then the second application will be secured with up to date content. But I can't find out how to lock a set of tables. If anyone knows how to do it plase help! Any kind of help would be appreciated!

thnxWhy not begin a transaction before changing the first table and then commit or rollback after changing the last table?|||You can do it by 2 ways

1) SET TRANSACTION ISOLATION LEVEL SERIALIZABLE
2)By Giving Lock hints on target tables (HOLDLOCK,TABLOCKX) --which is equivalent to SERIALIZABLE

more information on BOL for "lock hints"

vish

Originally posted by armen_gg
Hi all,

Let's image I have a set of tables (for ex. 3 tables) which are logically connected with each other (i.e. every time I'm changing something in one table I necessarily will make some changes to other 2 tables).
Well, now I have two application - one is changing these tables (synchronising tables' content with application's environment) and another one which time by time reading these tables and makes some operations base on tables' content.
The problem is - if the first application started changes but not commited transaction yet and the second application running SELECT clause, then I could get a "wrong" data in the second app, i.e. content of some tables will be updated but content of other tables are old.
The ways to solve this... I think that it's possible to lock these tables before making changes in the first application and unlock tables after changes are complete. Then the second application will be secured with up to date content. But I can't find out how to lock a set of tables. If anyone knows how to do it plase help! Any kind of help would be appreciated!

thnx