Drupal站点迁移未定义类常量“MYSQL_ATTR_USE_BUFFERED_QUERY”

我正在将Drupal站点迁移到本地环境。当前刷新浏览器时出现以下错误:

致命错误:未定义的类常量“MYSQL_ATTR_USE_BUFFERED_QUERY”

我读过,这可能是pdo_mysql扩展的问题。然而,我的似乎已安装并启用。还能是什么?

以下是php的相关摘录。ini文件:

extension_dir = C:/Program Files (x86)/Ampps/php/ext    

extension=php_sqlsrv_55_ts.dll
extension=php_pdo_sqlsrv_55_ts.dll

extension=php_bz2.dll
extension=php_curl.dll
;extension=php_fileinfo.dll
extension=php_gd2.dll
;extension=php_gettext.dll
;extension=php_gmp.dll
;extension=php_intl.dll
;extension=php_imap.dll
;extension=php_interbase.dll
;extension=php_ldap.dll
extension=php_mbstring.dll
;extension=php_exif.dll      ; Must be after mbstring as it depends on it
extension=php_mysql.dll
extension=php_mysqli.dl
extension=php_mssql.dll
;extension=php_oci8.dll      ; Use with Oracle 10gR2 Instant Client
;extension=php_oci8_11g.dll  ; Use with Oracle 11gR2 Instant Client
extension=php_openssl.dll
;extension=php_pdo_firebird.dll
extension=php_pdo_mysql.dll
;extension=php_pdo_oci.dll
extension=php_pdo_odbc.dll
;extension=php_pdo_pgsql.dll
extension=php_pdo_sqlite.dll
;extension=php_pgsql.dll
;extension=php_pspell.dll
;extension=php_shmop.dll

; The MIBS data available in the PHP distribution must be installed. 
; See http://www.php.net/manual/en/snmp.installation.php 
;extension=php_snmp.dll

extension=php_soap.dll
;extension=php_sockets.dll
extension=php_sqlite3.dll
;extension=php_tidy.dll
extension=php_xmlrpc.dll
;extension=php_xsl.dll
extension=php_com_dotnet.dll
extension=php_mongo.dll