Kirsten Greed
Sat, 04 Feb 2012 18:26:09 -0800
Hi Greg Um what types are there?
I was hoping for the user experience to be that they hit a refresh button and an asynch process pulls down data that other users have added and puts up new data that the user has added. Although that might be ambitions I was wondering just how ambitious it is Is it similar to database replication? Thanks Kirsten _____ From: sqldownunder-boun...@list.sqldownunder.com [mailto:sqldownunder-boun...@list.sqldownunder.com] On Behalf Of Greg Low (GregLow.com) Sent: Sunday, 5 February 2012 11:41 AM To: 'SQLDownUnder' Subject: RE: Guids vs Integers for primary keys? Performance? Hi Kirsten, What type of synching are you trying to achieve? Regards, Dr Greg Low 1300SQLSQL (1300 775 775) office | +61 419201410 mobile│ +61 3 8676 4913 fax SQL Down Under | Web: <http://www.sqldownunder.com/> www.sqldownunder.com From: sqldownunder-boun...@list.sqldownunder.com [mailto:sqldownunder-boun...@list.sqldownunder.com] <mailto:%5bmailto:sqldownunder-boun...@list.sqldownunder.com%5d> On Behalf Of Kirsten Greed Sent: Sunday, 5 February 2012 9:21 AM To: 'SQLDownUnder' Subject: RE: Guids vs Integers for primary keys? Performance? Hi Nick, Greg, Dave Thanks for your help. I am feeling inspired to stay away from Guids as primary keys. The application is a business app with several tables having hundreds of thousands of records. I am wondering about tools for syncing? Dave's comments that I need to carefully plan things out, and Greg's about having a table that maps between synchronised tables makes me think that the sync framework is not a candidate. Kirsten _____ From: sqldownunder-boun...@list.sqldownunder.com [mailto:sqldownunder-boun...@list.sqldownunder.com] <mailto:%5bmailto:sqldownunder-boun...@list.sqldownunder.com%5d> On Behalf Of Nicholas Kavadias Sent: Saturday, 4 February 2012 5:29 PM To: SQLDownUnder Subject: RE: Guids vs Integers for primary keys? Performance? My 2 cents: If you do decide on guids, use newsequentialid() to generate values http://www.fotia.co.uk/fotia/DY.19.NewSequentialId.aspx Enjoy the rest of your weekend. Nick On Feb 4, 2012 4:41 PM, "Greg Low" <g...@solidq.com> wrote: The other main thing is that there often seems to be a presumption that you have to have your logical data model the same as your physical data model. You don't. For example, rather than having all your tables that have a customer ID having the GUID, you can always have ints or bigints all over the place, and just have one table that maps between them. Regards, Greg Dr Greg Low | SolidQ | +61.4.1920.1410 <tel:%2B61.4.1920.1410> mobile | +61.3.8676.4913 <tel:%2B61.3.8676.4913> fax From: sqldownunder-boun...@list.sqldownunder.com [mailto:sqldownunder-boun...@list.sqldownunder.com] On Behalf Of Dave Dustin Sent: Saturday, 4 February 2012 4:22 PM To: 'SQLDownUnder' Subject: Re: Guids vs Integers for primary keys? Performance? Everybody must be out relaxing in the sun given the lack of responses... If you're considering using GUIDs as the primary key, please DO NOT make them also the Clustered index unless you want to take a SERIOUS performance hit. Using GUIDs for linking is a commonly implemented pattern, but you need to plan it out in advance. - What will be generating the GUID, the app or the database? - How many rows are you looking at? A GUID (stored as a UNIQUEIDENTIFIER) will consume 16bytes. An INT (most common IDENTITY datatype) is only 4. You'll need to take that into account when planning indexes and database diskspace requirements... - There may be an overhead for CASTing between the database and the application when passing the GUID around, depending what format it's being delivered in. Cheers Dave From: Kirsten Greed <mailto:kirst...@jobtalk.com.au> Sent: Saturday, February 04, 2012 1:59 PM To: 'SQLDownUnder' <mailto:sqldownunder@list.sqldownunder.com> Subject: Guids vs Integers for primary keys? Performance? Hello All I want to make my application work in an occasionally connected mode and am thinking of the Sync Framework as the way to do it. However I currently use identity primary keys and would probably need to change to using GUIDS as primary keys Many of my queries involve 5 or more tables - should I expect much of a performance hit if I make the change? Thanks Kirsten _____ _______________________________________________ sqldownunder mailing list sqldownunder@list.sqldownunder.com http://prdlxvm0001.codify.net/mailman/listinfo/sqldownunder _______________________________________________ sqldownunder mailing list sqldownunder@list.sqldownunder.com http://prdlxvm0001.codify.net/mailman/listinfo/sqldownunder __________ Information from ESET NOD32 Antivirus, version of virus signature database 6777 (20120108) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com
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