Comments on: To Insert or To Update http://particletree.com/notebook/to-insert-or-to-update/ Everyone needs a hug. Wed, 08 Oct 2008 06:08:44 +0000 http://wordpress.org/?v=2.6.2 By: JayantB http://particletree.com/notebook/to-insert-or-to-update/#comment-24248 JayantB Sat, 13 Oct 2007 19:04:05 +0000 http://particletree.com/notebook/to-insert-or-to-update/#comment-24248 <p>I have following table</p> <p>Product</p> <p>ProductID ProductRangeID ProductName Desc StatusFlag</p> <p>1 1 Metal abc I</p> <p>2 2 Wood xyz I</p> <p>3 3 JDB pqr I</p> <p>4 1 OM XXX I</p> <p>5 2 Shiv KKK I</p> <p>I need to check Duplicate ProductName against same ProductRangeID before Inserting and Updating the values I want to Insert and update values in single procedure</p> <p>How I can Do it??? please help??</p> I have following table

Product

ProductID ProductRangeID ProductName Desc StatusFlag

1 1 Metal abc I

2 2 Wood xyz I

3 3 JDB pqr I

4 1 OM XXX I

5 2 Shiv KKK I

I need to check Duplicate ProductName against same ProductRangeID before Inserting and Updating the values I want to Insert and update values in single procedure

How I can Do it??? please help??

]]> By: Greg Jorgensen http://particletree.com/notebook/to-insert-or-to-update/#comment-24204 Greg Jorgensen Mon, 08 Oct 2007 06:09:29 +0000 http://particletree.com/notebook/to-insert-or-to-update/#comment-24204 <p>MySQL has the non-standard ON DUPLICATE KEY and the (dangerous) REPLACE statement. If you are using some other RDBMS, or you want to steer clear of MySQL quirks, just try whatever is least likely to fail (INSERT or UPDATE) and if it fails do the other. Whether you do a SELECT first, try to INSERT a duplicate primary key, or try to UPDATE a non-existent row the RDBMS does exactly the same amount of work: it scans the primary key index to see if the key you are looking for is in the index.</p> <p>If you have a table that is frequently updated, just do the UPDATE, then check the number of affected rows. If zero rows were updated do the INSERT. Likewise if the rows in your table are usually not updated after they are inserted do the INSERT, and if it fails (check the number of rows again) do an UPDATE.</p> <p>You can also just DELETE before INSERTING if your UPDATE will affect all columns anyway. The DELETE won't do anything if there's no matching row. Remember to put the DELETE and INSERT inside a transaction.</p> <p>SQL operations don't blow up or corrupt the database if they fail, and they don't crash your application or throw and exception. Just look at the number of affected rows to see if your INSERT, UPDATE, or DELETE did anything or not.</p> MySQL has the non-standard ON DUPLICATE KEY and the (dangerous) REPLACE statement. If you are using some other RDBMS, or you want to steer clear of MySQL quirks, just try whatever is least likely to fail (INSERT or UPDATE) and if it fails do the other. Whether you do a SELECT first, try to INSERT a duplicate primary key, or try to UPDATE a non-existent row the RDBMS does exactly the same amount of work: it scans the primary key index to see if the key you are looking for is in the index.

If you have a table that is frequently updated, just do the UPDATE, then check the number of affected rows. If zero rows were updated do the INSERT. Likewise if the rows in your table are usually not updated after they are inserted do the INSERT, and if it fails (check the number of rows again) do an UPDATE.

You can also just DELETE before INSERTING if your UPDATE will affect all columns anyway. The DELETE won’t do anything if there’s no matching row. Remember to put the DELETE and INSERT inside a transaction.

SQL operations don’t blow up or corrupt the database if they fail, and they don’t crash your application or throw and exception. Just look at the number of affected rows to see if your INSERT, UPDATE, or DELETE did anything or not.

]]> By: Blomus http://particletree.com/notebook/to-insert-or-to-update/#comment-24124 Blomus Mon, 01 Oct 2007 05:07:34 +0000 http://particletree.com/notebook/to-insert-or-to-update/#comment-24124 <p>It is very useful. Thank you for posting Ryan</p> It is very useful. Thank you for posting Ryan

]]> By: Sridhar http://particletree.com/notebook/to-insert-or-to-update/#comment-24119 Sridhar Sun, 30 Sep 2007 06:20:31 +0000 http://particletree.com/notebook/to-insert-or-to-update/#comment-24119 <p>i second Alan Wallace's comment. Thanks for posting Ryan.</p> i second Alan Wallace’s comment. Thanks for posting Ryan.

]]> By: Murtaza http://particletree.com/notebook/to-insert-or-to-update/#comment-24110 Murtaza Sat, 29 Sep 2007 09:58:26 +0000 http://particletree.com/notebook/to-insert-or-to-update/#comment-24110 <p>A very helpful indeed. Thanks for posting Ryan</p> A very helpful indeed. Thanks for posting Ryan

]]> By: Aron http://particletree.com/notebook/to-insert-or-to-update/#comment-24086 Aron Fri, 28 Sep 2007 10:13:07 +0000 http://particletree.com/notebook/to-insert-or-to-update/#comment-24086 <p>For as far as I know, REPLACE INTO deletes the existing record and inserts a new one, when a duplicate key is found.</p> For as far as I know, REPLACE INTO deletes the existing record and inserts a new one, when a duplicate key is found.

]]> By: Harmen Janssen http://particletree.com/notebook/to-insert-or-to-update/#comment-24085 Harmen Janssen Fri, 28 Sep 2007 09:40:36 +0000 http://particletree.com/notebook/to-insert-or-to-update/#comment-24085 <p>A very helpful post, thanks for this little gem. This'll certainly unclutter some of my code.</p> A very helpful post, thanks for this little gem. This’ll certainly unclutter some of my code.

]]> By: Rahul http://particletree.com/notebook/to-insert-or-to-update/#comment-24079 Rahul Thu, 27 Sep 2007 19:48:39 +0000 http://particletree.com/notebook/to-insert-or-to-update/#comment-24079 <p>Ever heard of REPLACE INTO?</p> Ever heard of REPLACE INTO?

]]> By: Alan Wallace http://particletree.com/notebook/to-insert-or-to-update/#comment-24078 Alan Wallace Thu, 27 Sep 2007 19:31:12 +0000 http://particletree.com/notebook/to-insert-or-to-update/#comment-24078 <p>Love these short helpful posts. I've been doing this in the way of the first example, will be glad to remove some more cludge from my code.</p> Love these short helpful posts. I’ve been doing this in the way of the first example, will be glad to remove some more cludge from my code.

]]> By: Ryan Campbell http://particletree.com/notebook/to-insert-or-to-update/#comment-24076 Ryan Campbell Thu, 27 Sep 2007 18:39:16 +0000 http://particletree.com/notebook/to-insert-or-to-update/#comment-24076 <p>I believe that has been fixed. The last comment says it has, but I have also read a few blog posts where people claim that they have noticed a speed increase with replication using this technique. I haven't tested myself though, so I can't confirm.</p> I believe that has been fixed. The last comment says it has, but I have also read a few blog posts where people claim that they have noticed a speed increase with replication using this technique. I haven’t tested myself though, so I can’t confirm.

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