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<center>
<h1>Executing stored procedures</h1>
</center>
<p>Calling (executing) a stored procedure (function) requires the following steps:</p>
<OL>
<li>Create a command object and pass stored
procedure name to it.
<li> Bind input parameters
<li> Execute stored procedure
<li>Process output parameters and possibly result set</li></OL>
<p>Suppose, we want to call a procedure
<EM>TestProc</EM> with two numeric parameters <EM>n1</EM> and
<EM>n2</EM> where <EM>n1</EM> is input parameter and <EM>n2</EM> is
input/output parameter. Procedure will add <EM>n1</EM> and
<EM>n2</EM> and assign the result to <EM>n2</EM> (<EM>n2 =
n1+n2</EM> ).</p>
<h4>Step 1. Creating a command object and passing stored procedure name to it.</h4>
<p>As usual, the first thing to do is to create
the objects. To execute a stored procedure we need two objects: <A
href="../OnLineDoc/Connection.html">SAConnection</A>
(connection object) and <A
href="../OnLineDoc/Command.html">SACommand</A>
(command object).</p>
<p><STRONG><FONT face="" size=2><FONT
face=System>SACommand cmd(&Connection,
"TestProc");</FONT></FONT></STRONG><FONT><FONT
face=System></FONT></FONT> </p>
<p>The line above creates a command object
<EM>cmd</EM> based on previously created and connected connection
object <EM>Connection</EM> (for creating and connection
<EM>Connection</EM>
object see <A href="connect.html">Connecting to
databases</A>).
Second parameter is the name of the required procedure. Required
procedure can also be provided using <A
href="../OnLineDoc/Command_setCommandText.html">SACommand::setCommandText</A>
method.</p>
<p><FONT face=System size=2><STRONG>SACommand
cmd(&Connection);<BR> cmd.setCommandText("TestProc");</STRONG></FONT> </p>
<p><FONT face=System
size=2><STRONG></STRONG></FONT> </p>
<h4> Step 2. Binding input parameters</h4>
<p>After parameters are created (automatically by the
Library or manually) they all initialized to null values. There are two methods of assigning values to them.</p>
<p><STRONG>First: </STRONG> using ordinary assignment:</p>
<p><STRONG><FONT face=System
size=2>cmd.Param("n1").setAsLong() =
5;<BR>cmd.Param("n2").setAsLong() =
10;</FONT></STRONG>
</p>
<p><STRONG>Second: </STRONG> using stream binding operator:</p>
<p><STRONG><FONT face=System size=2>cmd
<< SAPos("n1") << 5 <<
SAPos("n2") << 10;</FONT></STRONG> </p>
<p><STRONG><FONT face=System
size=2></FONT></STRONG> </p>
<h4> Step 3. Executing stored procedure</h4>
<p>To actually execute a procedure call <A
href="../OnLineDoc/Command_Execute.html">SACommand::Execute</A> method.</p>
<p><STRONG><FONT face=System
size=2>cmd.Execute();</FONT></STRONG> </p>
<p> </p>
<h4>Step 4. Processing output parameters and possibly result set(s)</h4>
<p>If stored procedure does not generate result
set(s) you can reach output parameters immediately after calling
<A
href="../OnLineDoc/Command_Execute.html" >SACommand::Execute</A>
:</p>
<p><STRONG><FONT face=System
size=2>printf("%d\n",
cmd.Param("n2").asLong());</FONT></STRONG> </p>
<p>After the statement has been executed,
SQLAPI++ stores the returned values of output parameters in the <A
href="../OnLineDoc/Param.html">SAParam</A>
objects bound to those parameters. On some servers these
returned values are not guaranteed to be set until all results
returned by the procedure have been fetched (using
<A href="../OnLineDoc/Command_FetchNext.html" >SACommand::FetchNext</A>
method). See <A href="../ServerSpecific/index.html">Server specific
information</A>
on output parameters
availability on different
DBMSs.</p>
<P>For processing result set(s) (if any) see <A
href="fetch.html"
>Fetching result set</A>
and <A
href="fetch_multiple.html">Fetching multiple result sets</A>.</P>
<p>That is all there is to it. <STRONG>Steps
2-4</STRONG> can be
repeated if you need to call procedure several times.</p>
<p>
</p>
<h3>Problems and Questions</h3>
<p>If you don't find the answer to you
questions or have some problems on using the Library, please, send
e-mail to <A href="mailto:howto@sqlapi.com" >howto@sqlapi.com</A>. </p>
<p> </p>
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