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<h1 class="topictitle1">SQLPrepare - Prepare a statement</h1>
<div><div class="section"></div>
<div class="section"><h4 class="sectiontitle">Purpose</h4> <p><samp class="codeph">SQLPrepare()</samp> associates
an SQL statement with the input statement handle and sends the statement to
the DBMS to be prepared. The application can reference this prepared statement
by passing the statement handle to other functions.</p>
<p>If the statement
handle has been used with a SELECT statement, <samp class="codeph">SQLFreeStmt()</samp> must
be called to close the cursor, before calling <samp class="codeph">SQLPrepare()</samp>.</p>
</div>
<div class="section"><h4 class="sectiontitle">Syntax</h4><pre>SQLRETURN SQLPrepare (SQLHSTMT hstmt,
SQLCHAR *szSqlStr,
SQLINTEGER cbSqlStr);</pre>
</div>
<div class="section"><h4 class="sectiontitle">Function arguments</h4>
<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" width="100%" frame="hsides" border="1" rules="all"><caption>Table 1. SQLPrepare arguments</caption><thead align="left"><tr><th align="left" valign="top" width="20%" id="d0e56">Data type</th>
<th align="left" valign="top" width="20%" id="d0e58">Argument</th>
<th align="left" valign="top" width="20%" id="d0e60">Use</th>
<th align="left" valign="top" width="40%" id="d0e62">Description</th>
</tr>
</thead>
<tbody><tr><td align="left" valign="top" width="20%" headers="d0e56 ">SQLCHAR *</td>
<td align="left" valign="top" width="20%" headers="d0e58 "><em>szSqlStr</em></td>
<td align="left" valign="top" width="20%" headers="d0e60 ">Input</td>
<td align="left" valign="top" width="40%" headers="d0e62 ">SQL statement string.</td>
</tr>
<tr><td align="left" valign="top" width="20%" headers="d0e56 ">SQLHSTMT</td>
<td align="left" valign="top" width="20%" headers="d0e58 "><em>hstmt</em></td>
<td align="left" valign="top" width="20%" headers="d0e60 ">Input</td>
<td align="left" valign="top" width="40%" headers="d0e62 ">Statement handle. There must not be an open
cursor associated with <em>hstmt</em>.</td>
</tr>
<tr><td align="left" valign="top" width="20%" headers="d0e56 ">SQLINTEGER</td>
<td align="left" valign="top" width="20%" headers="d0e58 "><em>cbSqlStr</em></td>
<td align="left" valign="top" width="20%" headers="d0e60 ">Input</td>
<td align="left" valign="top" width="40%" headers="d0e62 ">Length of contents of <em>szSqlStr</em> argument.
<p>This must be set to either the exact length of the SQL statement in <em>szSqlstr</em>,
or to SQL_NTS if the statement text is null-terminated.</p>
</td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="section"><h4 class="sectiontitle">Usage</h4><div class="p">As soon as a statement has been prepared using <samp class="codeph">SQLPrepare()</samp>,
the application can request information about the format of the result set
(if it is a SELECT statement) by calling: <ul><li><samp class="codeph">SQLNumResultCols()</samp></li>
<li><samp class="codeph">SQLDescribeCol()</samp></li>
<li><samp class="codeph">SQLColAttributes()</samp></li>
</ul>
</div>
<p>A prepared statement can be processed once, or multiple times
by calling <samp class="codeph">SQLExecute()</samp>. The SQL statement remains associated
with the statement handle until the handle is used with another <samp class="codeph">SQLPrepare()</samp>, <samp class="codeph">SQLExecDirect()</samp>, <samp class="codeph">SQLColumns()</samp>, <samp class="codeph">SQLSpecialColumns()</samp>, <samp class="codeph">SQLStatistics()</samp>,
or <samp class="codeph">SQLTables()</samp>.</p>
<p>The SQL statement string might contain
parameter markers. A parameter marker is represented by a "?" character, and
indicates a position in the statement where the value of an application variable
is to be substituted, when <samp class="codeph">SQLExecute()</samp> is called. <samp class="codeph">SQLBindParam()</samp> is
used to bind (or associate) an application variable to each parameter marker,
and to indicate if any data conversion should be performed at the time the
data is transferred.</p>
<p>The SQL statement cannot be a COMMIT or ROLLBACK. <samp class="codeph">SQLTransact()</samp> must
be called to issue COMMIT or ROLLBACK.</p>
<p>If the SQL statement is a positioned
DELETE or a Positioned UPDATE, the cursor referenced by the statement must
be defined on a separate statement handle under the same connection handle.</p>
</div>
<div class="section"><h4 class="sectiontitle">Return codes</h4><ul><li>SQL_SUCCESS</li>
<li>SQL_SUCCESS_WITH_INFO</li>
<li>SQL_ERROR</li>
<li>SQL_INVALID_HANDLE</li>
</ul>
</div>
<div class="section"><h4 class="sectiontitle">Diagnostics</h4>
<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" width="100%" frame="hsides" border="1" rules="rows"><caption>Table 2. SQLPrepare SQLSTATEs</caption><thead align="left"><tr><th align="left" valign="top" width="25%" id="d0e189">SQLSTATE</th>
<th align="left" valign="top" width="25%" id="d0e191">Description</th>
<th align="left" valign="top" width="50%" id="d0e193">Explanation</th>
</tr>
</thead>
<tbody><tr><td align="left" valign="top" width="25%" headers="d0e189 "><strong>24</strong>000</td>
<td align="left" valign="top" width="25%" headers="d0e191 ">Cursor state that is not valid</td>
<td align="left" valign="top" width="50%" headers="d0e193 ">There is an open cursor on the specified <em>hstmt</em>.</td>
</tr>
<tr><td align="left" valign="top" width="25%" headers="d0e189 "><strong>37</strong>xxx</td>
<td align="left" valign="top" width="25%" headers="d0e191 ">Syntax error or access violation</td>
<td align="left" valign="top" width="50%" headers="d0e193 "><em>szSqlStr</em> contained one or more of
the following statements: <ul><li>A COMMIT</li>
<li>A ROLLBACK</li>
<li>An SQL statement that the connected database server cannot prepare</li>
<li>A statement containing a syntax error</li>
</ul>
</td>
</tr>
<tr><td align="left" valign="top" width="25%" headers="d0e189 "><strong>HY</strong>001</td>
<td align="left" valign="top" width="25%" headers="d0e191 ">Memory allocation failure</td>
<td align="left" valign="top" width="50%" headers="d0e193 ">The driver is unable to allocate memory required
to support the processing or completion of the function.</td>
</tr>
<tr><td align="left" valign="top" width="25%" headers="d0e189 "><strong>HY</strong>009</td>
<td align="left" valign="top" width="25%" headers="d0e191 ">Argument value that is not valid</td>
<td align="left" valign="top" width="50%" headers="d0e193 "><em>szSqlStr</em> is a null pointer. <p>The
argument <em>cbSqlStr</em> is less than 1, but not equal to SQL_NTS.</p>
</td>
</tr>
<tr><td align="left" valign="top" width="25%" headers="d0e189 "><strong>HY</strong>013 <strong>*</strong></td>
<td align="left" valign="top" width="25%" headers="d0e191 ">Memory management problem</td>
<td align="left" valign="top" width="50%" headers="d0e193 ">The driver is unable to access memory required
to support the processing or completion of the function.</td>
</tr>
<tr><td valign="top" width="25%" headers="d0e189 "><strong>HY</strong>021</td>
<td valign="top" width="25%" headers="d0e191 ">Internal descriptor that is not valid </td>
<td valign="top" width="50%" headers="d0e193 ">The internal descriptor cannot be addressed or allocated,
or it contains a value that is not valid.</td>
</tr>
</tbody>
</table>
</div>
<div class="note"><span class="notetitle">Note:</span> Not all Database Management Systems (DBMSs) report all of the
above diagnostic messages at prepare time. Therefore an application must also
be able to handle these conditions when calling <samp class="codeph">SQLExecute()</samp>.</div>
</div>
<div class="section"><h4 class="sectiontitle">Example</h4></div>
<div class="example" id="rzadpfnprep__xmprep"><a name="rzadpfnprep__xmprep"><!-- --></a><div class="p">Refer to <a href="rzadpxminter.htm#rzadpxminter">Example: Interactive SQL and the equivalent DB2 UDB CLI function calls</a> for
a listing of the <samp class="codeph">check_error, initialize, and terminate</samp> functions
used in the following example.<div class="note"><span class="notetitle">Note:</span> By using the code examples, you agree
to the terms of the <a href="codedisclaimer.htm">Code license and disclaimer information</a>.</div>
<pre>/*************************************************************************
** file = prepare.c
**
** Example of preparing then repeatedly executing an SQL statement.
**
** Functions used:
**
** SQLAllocConnect SQLFreeConnect
** SQLAllocEnv SQLFreeEnv
** SQLAllocStmt SQLFreeStmt
** SQLConnect SQLDisconnect
**
** SQLBindCol SQLFetch
** SQLTransact SQLError
** SQLPrepare SQLSetParam
** SQLExecute
**************************************************************************/
#include &lt;stdio.h&gt;
#include &lt;string.h&gt;
#include &lt;stdlib.h&gt;
#include "sqlcli.h"
#define MAX_STMT_LEN 255
int initialize(SQLHENV *henv,
SQLHDBC *hdbc);
int terminate(SQLHENV henv,
SQLHDBC hdbc);
int print_error (SQLHENV henv,
SQLHDBC hdbc,
SQLHSTMT hstmt);
int check_error (SQLHENV henv,
SQLHDBC hdbc,
SQLHSTMT hstmt,
SQLRETURN rc);
/*******************************************************************
** main
** - initialize
** - terminate
*******************************************************************/
int main()
{
SQLHENV henv;
SQLHDBC hdbc;
SQLCHAR sqlstmt[MAX_STMT_LEN + 1]="";
SQLRETURN rc;
rc = initialize(&amp;henv, &amp;hdbc);
if (rc == SQL_ERROR) return(terminate(henv, hdbc));
{SQLHSTMT hstmt;
SQLCHAR sqlstmt[]="SELECT deptname, location from org where division = ?";
SQLCHAR deptname[15],
location[14],
division[11];
SQLINTEGER rlength,
plength;
rc = SQLAllocStmt(hdbc, &amp;hstmt);
if (rc != SQL_SUCCESS )
check_error (henv, hdbc, SQL_NULL_HSTMT, rc);
/* prepare statement for multiple use */
rc = SQLPrepare(hstmt, sqlstmt, SQL_NTS);
if (rc != SQL_SUCCESS )
check_error (henv, hdbc, hstmt, rc);
/* bind division to parameter marker in sqlstmt */
rc = SQLSetParam(hstmt, 1, SQL_CHAR, SQL_CHAR, 10, 10, division,
&amp;plength);
if (rc != SQL_SUCCESS )
check_error (henv, hdbc, hstmt, rc);
/* bind deptname to first column in the result set */
rc = SQLBindCol(hstmt, 1, SQL_CHAR, (SQLPOINTER) deptname, 15,
&amp;rlength);
if (rc != SQL_SUCCESS )
check_error (henv, hdbc, hstmt, rc);
rc = SQLBindCol(hstmt, 2, SQL_CHAR, (SQLPOINTER) location, 14,
&amp;rlength);
if (rc != SQL_SUCCESS )
check_error (henv, hdbc, hstmt, rc);
printf("\nEnter Division Name or 'q' to quit:\n");
printf("(Eastern, Western, Midwest, Corporate)\n");
gets(division);
plength = SQL_NTS;
while(division[0] != 'q')
{
rc = SQLExecute(hstmt);
if (rc != SQL_SUCCESS )
check_error (henv, hdbc, hstmt, rc);
printf("Departments in %s Division:\n", division);
printf("DEPTNAME Location\n");
printf("-------------- -------------\n");
while ((rc = SQLFetch(hstmt)) == SQL_SUCCESS)
{
printf("%-14.14s %-13.13s \n", deptname, location);
}
if (rc != SQL_NO_DATA_FOUND )
check_error (henv, hdbc, hstmt, rc);
SQLFreeStmt(hstmt, SQL_CLOSE);
printf("\nEnter Division Name or 'q' to quit:\n");
printf("(Eastern, Western, Midwest, Corporate)\n");
gets(division);
}
}
rc = SQLTransact(henv, hdbc, SQL_ROLLBACK);
if (rc != SQL_SUCCESS )
check_error (henv, hdbc, SQL_NULL_HSTMT, rc);
terminate(henv, hdbc);
return (0);
}/* end main */</pre>
</div>
</div>
<div class="section"><h4 class="sectiontitle">References</h4><ul><li><a href="rzadpfncolat.htm#rzadpfncolat">SQLColAttributes - Obtain column attributes</a></li>
<li><a href="rzadpfndecol.htm#rzadpfndecol">SQLDescribeCol - Describe column attributes</a></li>
<li><a href="rzadpfnexecd.htm#rzadpfnexecd">SQLExecDirect - Execute a statement directly</a></li>
<li><a href="rzadpfnexec.htm#rzadpfnexec">SQLExecute - Execute a statement</a></li>
<li><a href="rzadpfnnrcol.htm#rzadpfnnrcol">SQLNumResultCols - Get number of result columns</a></li>
</ul>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="rzadphdapi.htm" title="This topic provides a description of each CLI function.">DB2 UDB CLI functions</a></div>
</div>
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