Hendra-
Although defining RI does cause a tiny bit of overhead when you delete a child row, change the Foreign Key in a child row, or delete a parent row, it is almost not measurable. The benefit of avoiding "orphan" child rows far outweighs the small amount of overhead. "Someone" mislead you.
John Viescas, author
Microsoft Office Access 2010 Inside Out
Microsoft Office Access 2007 Inside Out
Building Microsoft Access Applications
Microsoft Office Access 2003 Inside Out
SQL Queries for Mere Mortals
http://www.viescas.com/
(Kirkland, WA)
-----Original Message-----
From: MS_Access_Professionals@yahoogroups.com [mailto:MS_Access_Professionals@yahoogroups.com] On Behalf Of Agestha Hendra
Sent: Monday, February 27, 2012 3:53 PM
To: MS_Access_Professionals@yahoogroups.com
Subject: Bls: [MS_AccessPros] Relationships
Thanx Jhon,...
The reason i do not buid relationships between tables and not implement RI is because someone told me that
building relationships between tables will make slow all of the process like u said...but yes it causing
more effort to delete all the records on Child after i delete the records on parents..
But u said "small performance advantage"...how small is that ? i have to rethinking to use RI again if the
advantage of not using RI just small...i never yet implemented my application in network, multi user and
mush data, so i can't see the diffrence about using or not the RI...in my PC all are look the same performance
because only single user and still not much data
Regards
Hendra
________________________________
Dari: John Viescas <john@viescas.com>
Kepada: MS_Access_Professionals@yahoogroups.com
Dikirim: Senin, 27 Februari 2012 22:43
Judul: RE: [MS_AccessPros] Relationships
Hendra-
You gain a small performance advantage by not defining referential integrity as
long as you define indexes on the Foreign Keys. When you have RI defined,
Access must probe the "parent" table each time you add a row in the "child"
table or change a FK value in the Child table. Why do you not want to define
RI? If you do decide to implement RI, be sure to delete all indexes on Foreign
Keys because Access will build an extra hidden index on the FK when you define
RI.
John Viescas, author
Microsoft Office Access 2010 Inside Out
Microsoft Office Access 2007 Inside Out
Building Microsoft Access Applications
Microsoft Office Access 2003 Inside Out
SQL Queries for Mere Mortals
http://www.viescas.com/
(Kirkland, WA)
-----Original Message-----
From: MS_Access_Professionals@yahoogroups.com
[mailto:MS_Access_Professionals@yahoogroups.com] On Behalf Of
agesthahendra@ymail.com
Sent: Monday, February 27, 2012 7:30 AM
To: MS_Access_Professionals@yahoogroups.com
Subject: [MS_AccessPros] Relationships
Hi All,..
Assumed :
- We have indexed all of the foreign key on many sides
- All Join are builded in Queries as we need
- Ignoring Enforce Reffrential Integrity
Do we still have to build relationships between tables..? What about
performance..? Are there any performance effects if we don't build relationships
between tables..?
Any explanation would be appreciated, thank you...
Regards
Hendra
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