Question

我需要使用PHP重命名MySQL表中的列。

这很难，因为语法是ALTER TABLE [table] CHANGE COLUMN [oldname] [newname] [definition]。该定义是必需参数。

有没有办法获取定义并简单地将其反馈到SQL语句中？一些示例代码非常棒，谢谢！

Answer 1

根据http://codingforums.com/showthread.php?t=148936，您可能需要解析SHOW CREATE TABLE的结果以获取当前定义，然后在ALTER语句中使用该结果。

mysql_fetch_field()也可能有用。

Answer 2

您可以阅读information_schema。 <击>
<击> SHOW TABLE STATUS [{FROM | IN} db_name] [LIKE 'pattern' | WHERE expr]

Answer 3

问题SHOW CREATE TABLE，读取描述感兴趣的列的行，确定列定义并构建您的ALTER TABLE语句。

Answer 4

我的解决方案是：

$table = "tableName";
$createTableSQL = $dbh->Execute('SHOW CREATE TABLE ' . $table);
$createTableSQL = $createTableSQL[0][1];

$mappingTable = "originalToDevMapping";

//get mapping
$sql = "SELECT origField, newField
        FROM " . $mappingTable;
$newColumns = $dbh->Execute($sql);

foreach ($newColumns as $newColumn) {
    if (strlen($newColumn['newField'])<1) {
        echo "***Removing*** " . $newColumn['origField'] . "<br><br>";

        $sql = "ALTER TABLE " . $table . " DROP COLUMN " . $newColumn['origField'];

        $dbh->Execute($sql);
        if (strlen($dbh->errorStr)>1) {
            echo "<br>************************<br>";
            echo "<br>ERROR:<br>";
            echo $dbh->errorStr;
            echo "<br>************************<br>";
        }

    } else {
        echo "Renaming " .  $newColumn['origField'] . " to " . $newColumn['newField'] . "<br><br>";
        $sql = "ALTER TABLE " . $table . " CHANGE COLUMN " . $newColumn['origField'] . " " . $newColumn['newField'];
        $fieldPos = strpos($createTableSQL,$newColumn['origField']);
        $definitionStart = $fieldPos + strlen($newColumn['origField']) + 2;
        $definitionEnd = strpos($createTableSQL,',',$definitionStart) - 1;
        $definition = substr($createTableSQL,$definitionStart,$definitionEnd-$definitionStart+1);

        //workaround - if enum type, comma is included.  
        if (strstr($definition,'enum')) {
            //look for comma after enum end bracket.
            $commaPos = strpos($createTableSQL, ',', strpos($createTableSQL,')',$definitionStart));
            $definition = substr($createTableSQL,$definitionStart,$commaPos-$definitionStart);
        }

        $dbh->Execute($sql . " " . $definition);
        if (strlen($dbh->errorStr)>1) {
            echo "<br>************************<br>";
            echo "ERROR:<br>";
            echo $dbh->errorStr;
            echo "<br>************************<br>";
        }


    }

}

MySQL在PHP中重命名列

4 个答案: