Solved

best way to get next ID in database table

Posted on 2010-09-13
8
1,025 Views
Last Modified: 2012-05-10
Hi Experts,
I want to save the data of a record to the database (which has many rows).  I will need to do this in a transaction.  I want to get what the next ID should be (without using auto-incrementing rows).  So I want some way of locking the table so that I can do the following:
- Lock the table
- Get the next logical ID I should use
- insert my rows
- unlock the table

Is there a way to do this without using database-specific calls?
I could do something like this:
while(true)  {
   while (lock table does not exist)  {
      create lock table
      query other table for max ID
      insert using MaxID + 1
      delete lock table
      return
   }
   sleep (2000)
}
0
Comment
Question by:thready
  • 4
  • 2
  • 2
8 Comments
 
LVL 3

Expert Comment

by:ghayasurrehman
ID: 33663455
insert into table () value ()
select @@scopeidenty


it will return the current id
0
 
LVL 1

Author Comment

by:thready
ID: 33663489
isn't this database-specific?
0
 
LVL 86

Expert Comment

by:jkr
ID: 33663492
>>Is there a way to do this without using database-specific calls?

If you can guarantee that no other process will be accessing the DB during such an operation - yes. If not, I cannot imagine any way that is not specific to the DB. However, if you can use ODBC (http://en.wikipedia.org/wiki/Open_Database_Connectivity), you can reduce the 'specificness' of that.
0
What is SQL Server and how does it work?

The purpose of this paper is to provide you background on SQL Server. It’s your self-study guide for learning fundamentals. It includes both the history of SQL and its technical basics. Concepts and definitions will form the solid foundation of your future DBA expertise.

 
LVL 3

Expert Comment

by:ghayasurrehman
ID: 33663502
yes, this is for MS sql server
0
 
LVL 1

Author Comment

by:thready
ID: 33663539
and wouldn't it depend on knowing how columns were created (like auto-incrementing) ?
0
 
LVL 1

Author Comment

by:thready
ID: 33664258
If I must use database-specific, would you know how to do it with Postgres?
0
 
LVL 86

Accepted Solution

by:
jkr earned 500 total points
ID: 33664327
0
 
LVL 1

Author Closing Comment

by:thready
ID: 33664420
gracius seignior
0

Featured Post

What is SQL Server and how does it work?

The purpose of this paper is to provide you background on SQL Server. It’s your self-study guide for learning fundamentals. It includes both the history of SQL and its technical basics. Concepts and definitions will form the solid foundation of your future DBA expertise.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article shows you how to optimize memory allocations in C++ using placement new. Applicable especially to usecases dealing with creation of large number of objects. A brief on problem: Lets take example problem for simplicity: - I have a G…
When table data gets too large to manage or queries take too long to execute the solution is often to buy bigger hardware or assign more CPUs and memory resources to the machine to solve the problem. However, the best, cheapest and most effective so…
The goal of the video will be to teach the user the difference and consequence of passing data by value vs passing data by reference in C++. An example of passing data by value as well as an example of passing data by reference will be be given. Bot…
The viewer will learn how to user default arguments when defining functions. This method of defining functions will be contrasted with the non-default-argument of defining functions.

685 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question