Sql Server Sql Server 2005 Temp Tables

Understanding When `#Temporary Tables` Are Created in SQL Server 2005

In the world of SQL Server, particularly with version 2005, temporary tables play an important role in managing data efficiently within stored procedures. If you’ve ever found yourself wondering about the timing of when these #temporary tables are created, you’ve arrived at the right place!

The Question at Hand

In a stored procedure, when is the #Temptable created? Is it during the creation of the query execution plan or at the moment the stored procedure is executed?

To illustrate this, let’s look at a snippet of SQL code:

if (@x = 1)
    begin
        select 1 as Text into #Temptable
    end
else
    begin
        select 2 as Text into #Temptable
    end

Unpacking the Solution

To understand when #Temptable is created, we need to delve into the mechanics of SQL Server 2005.

Temporary Table Creation Timing

Execution of the Stored Procedure:
- Temporary tables prefixed with # are created when the stored procedure is executed, not during the creation of the query execution plan. This means that the table will only come into existence in response to the stored procedure’s execution.
Session Context:
- The temporary tables are session-specific. This means that any temp table you create will be accessible only in the SQL Server session where it is created. Once that session ends, the temporary table is automatically dropped.
Impact on Query Execution Plans:
- According to the research and references available, temporary tables are not part of the query execution plan generation process. They are created dynamically when the specific section of the code is executed.

Practical Considerations

When to Use Temporary Tables:
- Temporary tables are particularly useful when you need to hold intermediate results or perform complex manipulations without altering the primary database.
Managing Resources:
- Because these tables are session-specific, they help manage database resources effectively, preventing conflicts between different sessions accessing the same data.

Conclusion

In conclusion, if you’re working with #Temporary Tables in SQL Server 2005, remember that they are created at the point of execution of the stored procedure, not during the planning of the query. This allows you to utilize them flexibly within your code, providing a means to efficiently manage your data needs.

For further insights and a deeper understanding of query execution plans in SQL Server, consider checking out this helpful resource: SQL Server Performance.