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<refentry id="function.mysqli-prepare">
 <refnamediv>
  <refname>mysqli_prepare</refname>
  <refname>mysqli->prepare</refname>
  <refpurpose>Prepare a SQL statement for execution</refpurpose>
 </refnamediv>
 <refsect1>
  <title>Description</title>
  <para>Procedure style:</para>
  <methodsynopsis>
   <type>mysqli_stmt</type><methodname>mysqli_prepare</methodname>
   <methodparam><type>mysqli</type><parameter>link</parameter></methodparam>
   <methodparam><type>string</type><parameter>query</parameter></methodparam>
  </methodsynopsis>
  <para>Object oriented style (method)</para>
  <classsynopsis>
   <ooclass><classname>mysqli</classname></ooclass>
   <methodsynopsis>
    <type>mysqli_stmt</type><methodname>prepare</methodname>
    <methodparam><type>string</type><parameter>query</parameter></methodparam>
   </methodsynopsis>
  </classsynopsis>
  <para>
   <function>mysqli_prepare</function> prepares the SQL query pointed to by the
   null-terminated string query, and returns a statement handle to be used for
   further operations on the statement. The query must consist of a single SQL statement.
  </para>
  <note>
   <para>
    You should not add a terminating semicolon or <literal>\g</literal>
    to the statement.
   </para>
  </note>
  <para>
   The parameter <parameter>query</parameter>  can include one or more parameter markers
   in the SQL statement by embedding question mark (<literal>?</literal>) characters
   at the appropriate positions.
  </para>
  <note>
   <para>
    The markers are legal only in certain places in SQL statements.
    For example, they are allowed in the VALUES() list of an INSERT statement
    (to specify column values for a row), or in a comparison with a column in
    a WHERE clause to specify a comparison value.
   </para>
   <para>
    However, they are not allowed for identifiers (such as table or column names),
    in the select list that names the columns to be returned by a SELECT statement,
    or to specify both operands of a binary operator such as the <literal>=</literal>
    equal sign. The latter restriction is necessary because it would be impossible
    to determine the parameter type. It's not allowed to compare marker
    with <literal>NULL</literal> by <literal>? IS NULL</literal> too.
    In general, parameters are legal only in Data
    Manipulation Languange (DML) statements, and not in Data Defination Language
    (DDL) statements.
   </para>
  </note>
  <para>
   The parameter markers must be bound to application variables using
   <function>mysqli_stmt_bind_param</function> and/or <function>mysqli_stmt_bind_result</function>
   before executing the statement or fetching rows.
  </para>
 </refsect1>
 <refsect1>
  &reftitle.returnvalues;
  <para>
   <function>mysqli_prepare</function> returns a statement object or &false; if an error occured.
  </para>
 </refsect1>
 <refsect1>
  &reftitle.seealso;
  <para>
   <function>mysqli_stmt_execute</function>,
   <function>mysqli_stmt_fetch</function>,
   <function>mysqli_stmt_bind_param</function>,
   <function>mysqli_stmt_bind_result</function>&listendand;
   <function>mysqli_stmt_close</function>.
  </para>
 </refsect1>
 <refsect1>
  &reftitle.examples;
  <example>
   <title>Object oriented style</title>
   <programlisting role="php">
<![CDATA[
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

$city = "Amersfoort";

/* create a prepared statement */
if ($stmt = $mysqli->prepare("SELECT District FROM City WHERE Name=?")) {

    /* bind parameters for markers */
    $stmt->bind_param("s", $city);

    /* execute query */
    $stmt->execute();

    /* bind result variables */
    $stmt->bind_result($district);

    /* fetch value */
    $stmt->fetch();

    printf("%s is in district %s\n", $city, $district);

    /* close statement */
    $stmt->close();
}

/* close connection */
$mysqli->close();
?>
]]>
  </programlisting>
  </example>
  <example>
   <title>Procedural style</title>
   <programlisting role="php">
<![CDATA[
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

$city = "Amersfoort";

/* create a prepared statement */
if ($stmt = mysqli_prepare($link, "SELECT District FROM City WHERE Name=?")) {

    /* bind parameters for markers */
    mysqli_stmt_bind_param($stmt, "s", $city);

    /* execute query */
    mysqli_stmt_execute($stmt);

    /* bind result variables */
    mysqli_stmt_bind_result($stmt, $district);

    /* fetch value */
    mysqli_stmt_fetch($stmt);

    printf("%s is in district %s\n", $city, $district);

    /* close statement */
    mysqli_stmt_close($stmt);
}

/* close connection */
mysqli_close($link);
?>
]]>
   </programlisting>
  </example>
  &example.outputs;
  <screen>
<![CDATA[
Amersfoort is in district Utrecht
]]>
  </screen>
 </refsect1>
</refentry>

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