On Apr 23, 10:33 pm, "joeNOS...@[EMAIL PROTECTED]
" <joe.weinst...@[EMAIL PROTECTED]
>
wrote:
> On Apr 22, 11:46 pm, Taras_96 <taras...@[EMAIL PROTECTED]
> wrote:
>
> > I think my original question may have been unclear.
>
> > What is actually being done when a SQL statement is being 'compiled'?
> > Query plan? Parsing of SQL statement? Something else?
>
> > Thanks
>
> > Taras
>
> The driver sends the SQL string to the DBMS. The DBMS parses it, and
> compiles/creates a plan for executing what the SQL wants. This
> includes
> verifying the names of tables and columns etc, choosing what index to
> use etc. This plan may include place-holders for data values passed in
> as parameters. This is very similar to a session-scoped stored
> procedure.
> Then, when the driver sends the needed parameter values, and says
> 'go',
> the DBMS executes the plan. A plain statement does the same, all in
> one call,
> except the DBMS doesn't retain the plan, so even an immediate repeat
> of
> the exact same query requires the DBMS to re-parse, re-check, and re-
> plan,
> and re-execute.
> Joe Weinstein at BEA Systems
Excellent response - thanks Joe!
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