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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Returns metadata for a column in a result set</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="pdostatement.getattribute.html">PDOStatement->getAttribute</a></div> <div class="next" style="text-align: right; float: right;"><a href="pdostatement.nextrowset.html">PDOStatement->nextRowset</a></div> <div class="up"><a href="class.pdostatement.html">PDOStatement</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="pdostatement.getcolumnmeta" class="refentry"> <div class="refnamediv"> <h1 class="refname">PDOStatement->getColumnMeta</h1> <p class="verinfo">(No version information available, might be only in CVS)</p><p class="refpurpose"><span class="refname">PDOStatement->getColumnMeta</span> — <span class="dc-title"> Returns metadata for a column in a result set </span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">array</span> <span class="methodname"><b><b>PDOStatement::getColumnMeta</b></b></span> ( <span class="methodparam"><span class="type">int</span> <tt class="parameter">$column</tt></span> )</div> <div class="warning"><b class="warning">Warning</b><p class="simpara">This function is<em class="emphasis">EXPERIMENTAL</em>. The behaviour of this function, its name, andsurrounding documentation may change without notice in a future release of PHP.This function should be used at your own risk.</p></div> <p class="para"> Retrieves the metadata for a 0-indexed column in a result set as an associative array. </p> <div class="warning"><b class="warning">Warning</b> <p class="simpara"> Not all PDO drivers support <b>PDOStatement::getColumnMeta()</b>. </p> </div> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">column</tt></i></span> <dd> <p class="para"> The 0-indexed column in the result set. </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns an associative array containing the following values representing the metadata for a single column: </p> <table border="5"> <caption><b>Column metadata</b></caption> <colgroup> <col align="left" /> <col align="left" /> <thead valign="middle"> <tr valign="middle"> <th colspan="1">Name</th> <th colspan="1">Value</th> </tr> </thead> <tbody valign="middle" class="tbody"> <tr valign="middle"> <td colspan="1" rowspan="1" align="left"><i>native_type</i></td> <td colspan="1" rowspan="1" align="left">The PHP native type used to represent the column value.</td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left"><i>driver:decl_type</i></td> <td colspan="1" rowspan="1" align="left">The SQL type used to represent the column value in the database. If the column in the result set is the result of a function, this value is not returned by <b>PDOStatement::getColumnMeta()</b>. </td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left"><i>flags</i></td> <td colspan="1" rowspan="1" align="left">Any flags set for this column.</td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left"><i>name</i></td> <td colspan="1" rowspan="1" align="left">The name of this column as returned by the database.</td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left"><i>table</i></td> <td colspan="1" rowspan="1" align="left">The name of this column's table as returned by the database.</td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left"><i>len</i></td> <td colspan="1" rowspan="1" align="left">The length of this column. Normally <i>-1</i> for types other than floating point decimals.</td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left"><i>precision</i></td> <td colspan="1" rowspan="1" align="left">The numeric precision of this column. Normally <i>0</i> for types other than floating point decimals.</td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left"><i>pdo_type</i></td> <td colspan="1" rowspan="1" align="left">The type of this column as represented by the <i>PDO::PARAM_*</i> constants.</td> </tr> </tbody> </colgroup> </table> <p class="para"> Returns <b><tt>FALSE</tt></b> if the requested column does not exist in the result set, or if no result set exists. </p> </div> <div class="refsect1 changelog"> <h3 class="title">ChangeLog</h3> <p class="para"> <table class="informaltable"> <colgroup> <thead valign="middle"> <tr valign="middle"> <th colspan="1">Version</th> <th colspan="1">Description</th> </tr> </thead> <tbody valign="middle" class="tbody"> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">5.2.3</td> <td colspan="1" rowspan="1" align="left"><i>table</i> field</td> </tr> </tbody> </colgroup> </table> </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 Retrieving column metadata</b></p> <div class="example-contents"><p> The following example shows the results of retrieving the metadata for a single column generated by a function (COUNT) in a PDO_SQLITE driver. </p></div> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br />$select </span><span style="color: #007700">= </span><span style="color: #0000BB">$DB</span><span style="color: #007700">-></span><span style="color: #0000BB">query</span><span style="color: #007700">(</span><span style="color: #DD0000">'SELECT COUNT(*) FROM fruit'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$meta </span><span style="color: #007700">= </span><span style="color: #0000BB">$select</span><span style="color: #007700">-></span><span style="color: #0000BB">getColumnMeta</span><span style="color: #007700">(</span><span style="color: #0000BB">0</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$meta</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> <div class="example-contents"><p>The above example will output:</p></div> <div class="example-contents"><pre><div class="cdata"><pre>array(6) { ["native_type"]=> string(7) "integer" ["flags"]=> array(0) { } ["name"]=> string(8) "COUNT(*)" ["len"]=> int(-1) ["precision"]=> int(0) ["pdo_type"]=> int(2)}</pre></div> </pre></div> </div> </p> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><a href="pdostatement.columncount.html" class="function" rel="rdfs-seeAlso">PDOStatement::columnCount()</a></li> <li class="member"><a href="pdostatement.rowcount.html" class="function" rel="rdfs-seeAlso">PDOStatement::rowCount()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="pdostatement.getattribute.html">PDOStatement->getAttribute</a></div> <div class="next" style="text-align: right; float: right;"><a href="pdostatement.nextrowset.html">PDOStatement->nextRowset</a></div> <div class="up"><a href="class.pdostatement.html">PDOStatement</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
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