Friday, July 2, 2010

Temp Table Scope

One of the gotchas of TSQL is temp table scope. The fact that I can create a temp table within a stored procedure, then call a second stored procedure and reference that temp table, scares me a little. It reminds me of the 3G languages, with their global variables and modified private scope and such.

A big enhancement in SQL in this department: table variables. The scope of a table variable is the same as that of a "regular" variable - local to the scope of the procedure. So replacing the use of a temp table in a stored procedure eliminates the concern that a called inner procedure will unexpectedly change the data. However, there are major performance declines when using table variables to hold large amounts of data, as this article explains.

Another link:

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