Get last inserted record

If you are using SQL Server, you can also use the @@IDENTITY function in SQL Server and wrap the statement in the same query as the insert statement.  @@IDENTITY returns the very last ID that was inserted into the database,regardless of table.

For example:
<CFQUERY NAME="myQuery" DATASOURCE="myDataSource">
     INSERT INTO Table
          (Field1,
          Field2,
          Field3)
     VALUES
          ('Field1',
          'Field2',
          'Field3')

     SELECT @@IDENTITY AS RecordID
</CFQUERY>

<CFDUMP VAR="#myQuery.RecordID#">

This will insert the record and return its ID as a single process.

Enclose both your main CFQUERY and SELECT MAX() CFQUERY in CFTRANSACTION block.  Should work for most databases.

If you under MS SQL, @@IDENTITY is a better choice than MAX() - faster.

CFLOCK will work also, but, will be required everywhere, when you access the table, even for SELECTs.

<CFQUERY NAME="myQuery" DATASOURCE="myDataSource">
     INSERT INTO Table
          (Field1,
          Field2,
          Field3)
     VALUES
          ('Field1',
          'Field2',
          'Field3')

     SELECT SCOPE_IDENTITY() + 1 AS lastIdPlusOne
</CFQUERY>

on a high volume site you can have problems with a race condition.  In theory you can have 2 records inserted at almost the same instant.  cftransaction can cover this in most instances.

We use a different method because such race conditions have happened in all the scenarios we have tried above.

On the insert we have a UID we create with CreateUUID() and insert that into the record. Within the cftransaction we then do a select from where uid = the UId we just created.

<cfset thisUID = CreateUUID() />

<cftransaction>
 <CFQUERY NAME="myQuery" DATASOURCE="myDataSource">
     INSERT INTO Table
          (Field1,
          Field2,
         uniqueID)
     VALUES
          ('Field1',
          'Field2',
          #thisUID#)
</cfquery>
 <CFQUERY NAME="getId" DATASOURCE="myDataSource">
     SELECT id FROM Table
         WHERE uniqueID = #thisUID#
</cfquery>
</cftransaction>

In my view this is the only bullet proof way of accomplishing what you want on a scaleable basis.

actually @@identity should be fine if you are on SQL server 2000. SQL 7 doesnt support scope_identity().

http://weblogs.asp.net/rosherove/archive/2003/11/13/37217.aspx

I am also reliably informed that @@identity uses the SQL process id to retreive the last id passed in. So even if there were 2 'simultaneous' transactions you would end up with teh right number.

hi mrichmon,you can go ahead and delete the the duplication question, i thought somebody from the data base field would also give some vali answer rather than a programmer so thought of asking it in that section too aprt from coldfusion section. So anyways u can go ahead and delete it.

Thanks
an

Hey Pinal,
   Thanks for your answer but are u sure we would not have any problems about simultaneous transactions if we use cflock and retrive the max id for last inserted record, becoz mms98d1 suggested the use of UUID. But i guess if cflock works then i would want to use that. Also for your information the data would not be inserted by more than 8 peopls at a time.

So tell me what do u think

Thanks
Anup

Ok thanks for letting me know richmon

Anup

Richmon, what is your suggestion on my above comment about simultaneous transactions with the use of MAX() and lock?

Thanks
Anup

when its locked one transaction has to wait for the other, thats why you use locks...

So taco does it mean that it slows down the performance if there or more numebr of users?

This is a general question though coz i just have 6-7 simultaneous users in the worst case!

Anup