Added PEAR:DB support plus database replication support

1 files changed, 1076 insertions, 0 deletions

diff --git a/program/lib/DB/mysqli.php b/program/lib/DB/mysqli.php
new file mode 100644
index 000000000..bf742e27f
--- /dev/null
+++ b/program/lib/DB/mysqli.php
@@ -0,0 +1,1076 @@
+<?php
+
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+/**
+ * The PEAR DB driver for PHP's mysqli extension
+ * for interacting with MySQL databases
+ *
+ * PHP versions 4 and 5
+ *
+ * LICENSE: This source file is subject to version 3.0 of the PHP license
+ * that is available through the world-wide-web at the following URI:
+ * http://www.php.net/license/3_0.txt.  If you did not receive a copy of
+ * the PHP License and are unable to obtain it through the web, please
+ * send a note to license@php.net so we can mail you a copy immediately.
+ *
+ * @category   Database
+ * @package    DB
+ * @author     Daniel Convissor <danielc@php.net>
+ * @copyright  1997-2005 The PHP Group
+ * @license    http://www.php.net/license/3_0.txt  PHP License 3.0
+ * @version    CVS: $Id$
+ * @link       http://pear.php.net/package/DB
+ */
+
+/**
+ * Obtain the DB_common class so it can be extended from
+ */
+require_once 'DB/common.php';
+
+/**
+ * The methods PEAR DB uses to interact with PHP's mysqli extension
+ * for interacting with MySQL databases
+ *
+ * This is for MySQL versions 4.1 and above.  Requires PHP 5.
+ *
+ * Note that persistent connections no longer exist.
+ *
+ * These methods overload the ones declared in DB_common.
+ *
+ * @category   Database
+ * @package    DB
+ * @author     Daniel Convissor <danielc@php.net>
+ * @copyright  1997-2005 The PHP Group
+ * @license    http://www.php.net/license/3_0.txt  PHP License 3.0
+ * @version    Release: @package_version@
+ * @link       http://pear.php.net/package/DB
+ * @since      Class functional since Release 1.6.3
+ */
+class DB_mysqli extends DB_common
+{
+    // {{{ properties
+
+    /**
+     * The DB driver type (mysql, oci8, odbc, etc.)
+     * @var string
+     */
+    var $phptype = 'mysqli';
+
+    /**
+     * The database syntax variant to be used (db2, access, etc.), if any
+     * @var string
+     */
+    var $dbsyntax = 'mysqli';
+
+    /**
+     * The capabilities of this DB implementation
+     *
+     * The 'new_link' element contains the PHP version that first provided
+     * new_link support for this DBMS.  Contains false if it's unsupported.
+     *
+     * Meaning of the 'limit' element:
+     *   + 'emulate' = emulate with fetch row by number
+     *   + 'alter'   = alter the query
+     *   + false     = skip rows
+     *
+     * @var array
+     */
+    var $features = array(
+        'limit'         => 'alter',
+        'new_link'      => false,
+        'numrows'       => true,
+        'pconnect'      => false,
+        'prepare'       => false,
+        'ssl'           => true,
+        'transactions'  => true,
+    );
+
+    /**
+     * A mapping of native error codes to DB error codes
+     * @var array
+     */
+    var $errorcode_map = array(
+        1004 => DB_ERROR_CANNOT_CREATE,
+        1005 => DB_ERROR_CANNOT_CREATE,
+        1006 => DB_ERROR_CANNOT_CREATE,
+        1007 => DB_ERROR_ALREADY_EXISTS,
+        1008 => DB_ERROR_CANNOT_DROP,
+        1022 => DB_ERROR_ALREADY_EXISTS,
+        1044 => DB_ERROR_ACCESS_VIOLATION,
+        1046 => DB_ERROR_NODBSELECTED,
+        1048 => DB_ERROR_CONSTRAINT,
+        1049 => DB_ERROR_NOSUCHDB,
+        1050 => DB_ERROR_ALREADY_EXISTS,
+        1051 => DB_ERROR_NOSUCHTABLE,
+        1054 => DB_ERROR_NOSUCHFIELD,
+        1061 => DB_ERROR_ALREADY_EXISTS,
+        1062 => DB_ERROR_ALREADY_EXISTS,
+        1064 => DB_ERROR_SYNTAX,
+        1091 => DB_ERROR_NOT_FOUND,
+        1100 => DB_ERROR_NOT_LOCKED,
+        1136 => DB_ERROR_VALUE_COUNT_ON_ROW,
+        1142 => DB_ERROR_ACCESS_VIOLATION,
+        1146 => DB_ERROR_NOSUCHTABLE,
+        1216 => DB_ERROR_CONSTRAINT,
+        1217 => DB_ERROR_CONSTRAINT,
+    );
+
+    /**
+     * The raw database connection created by PHP
+     * @var resource
+     */
+    var $connection;
+
+    /**
+     * The DSN information for connecting to a database
+     * @var array
+     */
+    var $dsn = array();
+
+
+    /**
+     * Should data manipulation queries be committed automatically?
+     * @var bool
+     * @access private
+     */
+    var $autocommit = true;
+
+    /**
+     * The quantity of transactions begun
+     *
+     * {@internal  While this is private, it can't actually be designated
+     * private in PHP 5 because it is directly accessed in the test suite.}}
+     *
+     * @var integer
+     * @access private
+     */
+    var $transaction_opcount = 0;
+
+    /**
+     * The database specified in the DSN
+     *
+     * It's a fix to allow calls to different databases in the same script.
+     *
+     * @var string
+     * @access private
+     */
+    var $_db = '';
+
+    /**
+     * Array for converting MYSQLI_*_FLAG constants to text values
+     * @var    array
+     * @access public
+     * @since  Property available since Release 1.6.5
+     */
+    var $mysqli_flags = array(
+        MYSQLI_NOT_NULL_FLAG        => 'not_null',
+        MYSQLI_PRI_KEY_FLAG         => 'primary_key',
+        MYSQLI_UNIQUE_KEY_FLAG      => 'unique_key',
+        MYSQLI_MULTIPLE_KEY_FLAG    => 'multiple_key',
+        MYSQLI_BLOB_FLAG            => 'blob',
+        MYSQLI_UNSIGNED_FLAG        => 'unsigned',
+        MYSQLI_ZEROFILL_FLAG        => 'zerofill',
+        MYSQLI_AUTO_INCREMENT_FLAG  => 'auto_increment',
+        MYSQLI_TIMESTAMP_FLAG       => 'timestamp',
+        MYSQLI_SET_FLAG             => 'set',
+        // MYSQLI_NUM_FLAG             => 'numeric',  // unnecessary
+        // MYSQLI_PART_KEY_FLAG        => 'multiple_key',  // duplicatvie
+        MYSQLI_GROUP_FLAG           => 'group_by'
+    );
+
+    /**
+     * Array for converting MYSQLI_TYPE_* constants to text values
+     * @var    array
+     * @access public
+     * @since  Property available since Release 1.6.5
+     */
+    var $mysqli_types = array(
+        MYSQLI_TYPE_DECIMAL     => 'decimal',
+        MYSQLI_TYPE_TINY        => 'tinyint',
+        MYSQLI_TYPE_SHORT       => 'int',
+        MYSQLI_TYPE_LONG        => 'int',
+        MYSQLI_TYPE_FLOAT       => 'float',
+        MYSQLI_TYPE_DOUBLE      => 'double',
+        // MYSQLI_TYPE_NULL        => 'DEFAULT NULL',  // let flags handle it
+        MYSQLI_TYPE_TIMESTAMP   => 'timestamp',
+        MYSQLI_TYPE_LONGLONG    => 'bigint',
+        MYSQLI_TYPE_INT24       => 'mediumint',
+        MYSQLI_TYPE_DATE        => 'date',
+        MYSQLI_TYPE_TIME        => 'time',
+        MYSQLI_TYPE_DATETIME    => 'datetime',
+        MYSQLI_TYPE_YEAR        => 'year',
+        MYSQLI_TYPE_NEWDATE     => 'date',
+        MYSQLI_TYPE_ENUM        => 'enum',
+        MYSQLI_TYPE_SET         => 'set',
+        MYSQLI_TYPE_TINY_BLOB   => 'tinyblob',
+        MYSQLI_TYPE_MEDIUM_BLOB => 'mediumblob',
+        MYSQLI_TYPE_LONG_BLOB   => 'longblob',
+        MYSQLI_TYPE_BLOB        => 'blob',
+        MYSQLI_TYPE_VAR_STRING  => 'varchar',
+        MYSQLI_TYPE_STRING      => 'char',
+        MYSQLI_TYPE_GEOMETRY    => 'geometry',
+    );
+
+
+    // }}}
+    // {{{ constructor
+
+    /**
+     * This constructor calls <kbd>$this->DB_common()</kbd>
+     *
+     * @return void
+     */
+    function DB_mysqli()
+    {
+        $this->DB_common();
+    }
+
+    // }}}
+    // {{{ connect()
+
+    /**
+     * Connect to the database server, log in and open the database
+     *
+     * Don't call this method directly.  Use DB::connect() instead.
+     *
+     * PEAR DB's mysqli driver supports the following extra DSN options:
+     *   + When the 'ssl' $option passed to DB::connect() is true:
+     *     + key      The path to the key file.
+     *     + cert     The path to the certificate file.
+     *     + ca       The path to the certificate authority file.
+     *     + capath   The path to a directory that contains trusted SSL
+     *                 CA certificates in pem format.
+     *     + cipher   The list of allowable ciphers for SSL encryption.
+     *
+     * Example of how to connect using SSL:
+     * <code>
+     * require_once 'DB.php';
+     * 
+     * $dsn = array(
+     *     'phptype'  => 'mysqli',
+     *     'username' => 'someuser',
+     *     'password' => 'apasswd',
+     *     'hostspec' => 'localhost',
+     *     'database' => 'thedb',
+     *     'key'      => 'client-key.pem',
+     *     'cert'     => 'client-cert.pem',
+     *     'ca'       => 'cacert.pem',
+     *     'capath'   => '/path/to/ca/dir',
+     *     'cipher'   => 'AES',
+     * );
+     * 
+     * $options = array(
+     *     'ssl' => true,
+     * );
+     * 
+     * $db =& DB::connect($dsn, $options);
+     * if (PEAR::isError($db)) {
+     *     die($db->getMessage());
+     * }
+     * </code>
+     *
+     * @param array $dsn         the data source name
+     * @param bool  $persistent  should the connection be persistent?
+     *
+     * @return int  DB_OK on success. A DB_Error object on failure.
+     */
+    function connect($dsn, $persistent = false)
+    {
+        if (!PEAR::loadExtension('mysqli')) {
+            return $this->raiseError(DB_ERROR_EXTENSION_NOT_FOUND);
+        }
+
+        $this->dsn = $dsn;
+        if ($dsn['dbsyntax']) {
+            $this->dbsyntax = $dsn['dbsyntax'];
+        }
+
+        $ini = ini_get('track_errors');
+        ini_set('track_errors', 1);
+        $php_errormsg = '';
+
+        if ($this->getOption('ssl') === true) {
+            $init = mysqli_init();
+            mysqli_ssl_set(
+                $init,
+                empty($dsn['key'])    ? null : $dsn['key'],
+                empty($dsn['cert'])   ? null : $dsn['cert'],
+                empty($dsn['ca'])     ? null : $dsn['ca'],
+                empty($dsn['capath']) ? null : $dsn['capath'],
+                empty($dsn['cipher']) ? null : $dsn['cipher']
+            );
+            if ($this->connection = @mysqli_real_connect(
+                    $init,
+                    $dsn['hostspec'],
+                    $dsn['username'],
+                    $dsn['password'],
+                    $dsn['database'],
+                    $dsn['port'],
+                    $dsn['socket']))
+            {
+                $this->connection = $init;
+            }
+        } else {
+            $this->connection = @mysqli_connect(
+                $dsn['hostspec'],
+                $dsn['username'],
+                $dsn['password'],
+                $dsn['database'],
+                $dsn['port'],
+                $dsn['socket']
+            );
+        }
+
+        ini_set('track_errors', $ini);
+
+        if (!$this->connection) {
+            if (($err = @mysqli_connect_error()) != '') {
+                return $this->raiseError(DB_ERROR_CONNECT_FAILED,
+                                         null, null, null,
+                                         $err);
+            } else {
+                return $this->raiseError(DB_ERROR_CONNECT_FAILED,
+                                         null, null, null,
+                                         $php_errormsg);
+            }
+        }
+
+        if ($dsn['database']) {
+            $this->_db = $dsn['database'];
+        }
+
+        return DB_OK;
+    }
+
+    // }}}
+    // {{{ disconnect()
+
+    /**
+     * Disconnects from the database server
+     *
+     * @return bool  TRUE on success, FALSE on failure
+     */
+    function disconnect()
+    {
+        $ret = @mysqli_close($this->connection);
+        $this->connection = null;
+        return $ret;
+    }
+
+    // }}}
+    // {{{ simpleQuery()
+
+    /**
+     * Sends a query to the database server
+     *
+     * @param string  the SQL query string
+     *
+     * @return mixed  + a PHP result resrouce for successful SELECT queries
+     *                + the DB_OK constant for other successful queries
+     *                + a DB_Error object on failure
+     */
+    function simpleQuery($query)
+    {
+        $ismanip = DB::isManip($query);
+        $this->last_query = $query;
+        $query = $this->modifyQuery($query);
+        if ($this->_db) {
+            if (!@mysqli_select_db($this->connection, $this->_db)) {
+                return $this->mysqliRaiseError(DB_ERROR_NODBSELECTED);
+            }
+        }
+        if (!$this->autocommit && $ismanip) {
+            if ($this->transaction_opcount == 0) {
+                $result = @mysqli_query($this->connection, 'SET AUTOCOMMIT=0');
+                $result = @mysqli_query($this->connection, 'BEGIN');
+                if (!$result) {
+                    return $this->mysqliRaiseError();
+                }
+            }
+            $this->transaction_opcount++;
+        }
+        $result = @mysqli_query($this->connection, $query);
+        if (!$result) {
+            return $this->mysqliRaiseError();
+        }
+        if (is_object($result)) {
+            return $result;
+        }
+        return DB_OK;
+    }
+
+    // }}}
+    // {{{ nextResult()
+
+    /**
+     * Move the internal mysql result pointer to the next available result.
+     *
+     * This method has not been implemented yet.
+     *
+     * @param resource $result a valid sql result resource
+     * @return false
+     * @access public
+     */
+    function nextResult($result)
+    {
+        return false;
+    }
+
+    // }}}
+    // {{{ fetchInto()
+
+    /**
+     * Places a row from the result set into the given array
+     *
+     * Formating of the array and the data therein are configurable.
+     * See DB_result::fetchInto() for more information.
+     *
+     * This method is not meant to be called directly.  Use
+     * DB_result::fetchInto() instead.  It can't be declared "protected"
+     * because DB_result is a separate object.
+     *
+     * @param resource $result    the query result resource
+     * @param array    $arr       the referenced array to put the data in
+     * @param int      $fetchmode how the resulting array should be indexed
+     * @param int      $rownum    the row number to fetch (0 = first row)
+     *
+     * @return mixed  DB_OK on success, NULL when the end of a result set is
+     *                 reached or on failure
+     *
+     * @see DB_result::fetchInto()
+     */
+    function fetchInto($result, &$arr, $fetchmode, $rownum = null)
+    {
+        if ($rownum !== null) {
+            if (!@mysqli_data_seek($result, $rownum)) {
+                return null;
+            }
+        }
+        if ($fetchmode & DB_FETCHMODE_ASSOC) {
+            $arr = @mysqli_fetch_array($result, MYSQLI_ASSOC);
+            if ($this->options['portability'] & DB_PORTABILITY_LOWERCASE && $arr) {
+                $arr = array_change_key_case($arr, CASE_LOWER);
+            }
+        } else {
+            $arr = @mysqli_fetch_row($result);
+        }
+        if (!$arr) {
+            return null;
+        }
+        if ($this->options['portability'] & DB_PORTABILITY_RTRIM) {
+            /*
+             * Even though this DBMS already trims output, we do this because
+             * a field might have intentional whitespace at the end that
+             * gets removed by DB_PORTABILITY_RTRIM under another driver.
+             */
+            $this->_rtrimArrayValues($arr);
+        }
+        if ($this->options['portability'] & DB_PORTABILITY_NULL_TO_EMPTY) {
+            $this->_convertNullArrayValuesToEmpty($arr);
+        }
+        return DB_OK;
+    }
+
+    // }}}
+    // {{{ freeResult()
+
+    /**
+     * Deletes the result set and frees the memory occupied by the result set
+     *
+     * This method is not meant to be called directly.  Use
+     * DB_result::free() instead.  It can't be declared "protected"
+     * because DB_result is a separate object.
+     *
+     * @param resource $result  PHP's query result resource
+     *
+     * @return bool  TRUE on success, FALSE if $result is invalid
+     *
+     * @see DB_result::free()
+     */
+    function freeResult($result)
+    {
+        return @mysqli_free_result($result);
+    }
+
+    // }}}
+    // {{{ numCols()
+
+    /**
+     * Gets the number of columns in a result set
+     *
+     * This method is not meant to be called directly.  Use
+     * DB_result::numCols() instead.  It can't be declared "protected"
+     * because DB_result is a separate object.
+     *
+     * @param resource $result  PHP's query result resource
+     *
+     * @return int  the number of columns.  A DB_Error object on failure.
+     *
+     * @see DB_result::numCols()
+     */
+    function numCols($result)
+    {
+        $cols = @mysqli_num_fields($result);
+        if (!$cols) {
+            return $this->mysqliRaiseError();
+        }
+        return $cols;
+    }
+
+    // }}}
+    // {{{ numRows()
+
+    /**
+     * Gets the number of rows in a result set
+     *
+     * This method is not meant to be called directly.  Use
+     * DB_result::numRows() instead.  It can't be declared "protected"
+     * because DB_result is a separate object.
+     *
+     * @param resource $result  PHP's query result resource
+     *
+     * @return int  the number of rows.  A DB_Error object on failure.
+     *
+     * @see DB_result::numRows()
+     */
+    function numRows($result)
+    {
+        $rows = @mysqli_num_rows($result);
+        if ($rows === null) {
+            return $this->mysqliRaiseError();
+        }
+        return $rows;
+    }
+
+    // }}}
+    // {{{ autoCommit()
+
+    /**
+     * Enables or disables automatic commits
+     *
+     * @param bool $onoff  true turns it on, false turns it off
+     *
+     * @return int  DB_OK on success.  A DB_Error object if the driver
+     *               doesn't support auto-committing transactions.
+     */
+    function autoCommit($onoff = false)
+    {
+        // XXX if $this->transaction_opcount > 0, we should probably
+        // issue a warning here.
+        $this->autocommit = $onoff ? true : false;
+        return DB_OK;
+    }
+
+    // }}}
+    // {{{ commit()
+
+    /**
+     * Commits the current transaction
+     *
+     * @return int  DB_OK on success.  A DB_Error object on failure.
+     */
+    function commit()
+    {
+        if ($this->transaction_opcount > 0) {
+            if ($this->_db) {
+                if (!@mysqli_select_db($this->connection, $this->_db)) {
+                    return $this->mysqliRaiseError(DB_ERROR_NODBSELECTED);
+                }
+            }
+            $result = @mysqli_query($this->connection, 'COMMIT');
+            $result = @mysqli_query($this->connection, 'SET AUTOCOMMIT=1');
+            $this->transaction_opcount = 0;
+            if (!$result) {
+                return $this->mysqliRaiseError();
+            }
+        }
+        return DB_OK;
+    }
+
+    // }}}
+    // {{{ rollback()
+
+    /**
+     * Reverts the current transaction
+     *
+     * @return int  DB_OK on success.  A DB_Error object on failure.
+     */
+    function rollback()
+    {
+        if ($this->transaction_opcount > 0) {
+            if ($this->_db) {
+                if (!@mysqli_select_db($this->connection, $this->_db)) {
+                    return $this->mysqliRaiseError(DB_ERROR_NODBSELECTED);
+                }
+            }
+            $result = @mysqli_query($this->connection, 'ROLLBACK');
+            $result = @mysqli_query($this->connection, 'SET AUTOCOMMIT=1');
+            $this->transaction_opcount = 0;
+            if (!$result) {
+                return $this->mysqliRaiseError();
+            }
+        }
+        return DB_OK;
+    }
+
+    // }}}
+    // {{{ affectedRows()
+
+    /**
+     * Determines the number of rows affected by a data maniuplation query
+     *
+     * 0 is returned for queries that don't manipulate data.
+     *
+     * @return int  the number of rows.  A DB_Error object on failure.
+     */
+    function affectedRows()
+    {
+        if (DB::isManip($this->last_query)) {
+            return @mysqli_affected_rows($this->connection);
+        } else {
+            return 0;
+        }
+     }
+
+    // }}}
+    // {{{ nextId()
+
+    /**
+     * Returns the next free id in a sequence
+     *
+     * @param string  $seq_name  name of the sequence
+     * @param boolean $ondemand  when true, the seqence is automatically
+     *                            created if it does not exist
+     *
+     * @return int  the next id number in the sequence.
+     *               A DB_Error object on failure.
+     *
+     * @see DB_common::nextID(), DB_common::getSequenceName(),
+     *      DB_mysqli::createSequence(), DB_mysqli::dropSequence()
+     */
+    function nextId($seq_name, $ondemand = true)
+    {
+        $seqname = $this->getSequenceName($seq_name);
+        do {
+            $repeat = 0;
+            $this->pushErrorHandling(PEAR_ERROR_RETURN);
+            $result = $this->query('UPDATE ' . $seqname
+                                   . ' SET id = LAST_INSERT_ID(id + 1)');
+            $this->popErrorHandling();
+            if ($result === DB_OK) {
+                // COMMON CASE
+                $id = @mysqli_insert_id($this->connection);
+                if ($id != 0) {
+                    return $id;
+                }
+
+                // EMPTY SEQ TABLE
+                // Sequence table must be empty for some reason,
+                // so fill it and return 1
+                // Obtain a user-level lock
+                $result = $this->getOne('SELECT GET_LOCK('
+                                        . "'${seqname}_lock', 10)");
+                if (DB::isError($result)) {
+                    return $this->raiseError($result);
+                }
+                if ($result == 0) {
+                    return $this->mysqliRaiseError(DB_ERROR_NOT_LOCKED);
+                }
+
+                // add the default value
+                $result = $this->query('REPLACE INTO ' . $seqname
+                                       . ' (id) VALUES (0)');
+                if (DB::isError($result)) {
+                    return $this->raiseError($result);
+                }
+
+                // Release the lock
+                $result = $this->getOne('SELECT RELEASE_LOCK('
+                                        . "'${seqname}_lock')");
+                if (DB::isError($result)) {
+                    return $this->raiseError($result);
+                }
+                // We know what the result will be, so no need to try again
+                return 1;
+
+            } elseif ($ondemand && DB::isError($result) &&
+                $result->getCode() == DB_ERROR_NOSUCHTABLE)
+            {
+                // ONDEMAND TABLE CREATION
+                $result = $this->createSequence($seq_name);
+
+                // Since createSequence initializes the ID to be 1,
+                // we do not need to retrieve the ID again (or we will get 2)
+                if (DB::isError($result)) {
+                    return $this->raiseError($result);
+                } else {
+                    // First ID of a newly created sequence is 1
+                    return 1;
+                }
+
+            } elseif (DB::isError($result) &&
+                      $result->getCode() == DB_ERROR_ALREADY_EXISTS)
+            {
+                // BACKWARDS COMPAT
+                // see _BCsequence() comment
+                $result = $this->_BCsequence($seqname);
+                if (DB::isError($result)) {
+                    return $this->raiseError($result);
+                }
+                $repeat = 1;
+            }
+        } while ($repeat);
+
+        return $this->raiseError($result);
+    }
+
+    /**
+     * Creates a new sequence
+     *
+     * @param string $seq_name  name of the new sequence
+     *
+     * @return int  DB_OK on success.  A DB_Error object on failure.
+     *
+     * @see DB_common::createSequence(), DB_common::getSequenceName(),
+     *      DB_mysqli::nextID(), DB_mysqli::dropSequence()
+     */
+    function createSequence($seq_name)
+    {
+        $seqname = $this->getSequenceName($seq_name);
+        $res = $this->query('CREATE TABLE ' . $seqname
+                            . ' (id INTEGER UNSIGNED AUTO_INCREMENT NOT NULL,'
+                            . ' PRIMARY KEY(id))');
+        if (DB::isError($res)) {
+            return $res;
+        }
+        // insert yields value 1, nextId call will generate ID 2
+        return $this->query("INSERT INTO ${seqname} (id) VALUES (0)");
+    }
+
+    // }}}
+    // {{{ dropSequence()
+
+    /**
+     * Deletes a sequence
+     *
+     * @param string $seq_name  name of the sequence to be deleted
+     *
+     * @return int  DB_OK on success.  A DB_Error object on failure.
+     *
+     * @see DB_common::dropSequence(), DB_common::getSequenceName(),
+     *      DB_mysql::nextID(), DB_mysql::createSequence()
+     */
+    function dropSequence($seq_name)
+    {
+        return $this->query('DROP TABLE ' . $this->getSequenceName($seq_name));
+    }
+
+    // }}}
+    // {{{ _BCsequence()
+
+    /**
+     * Backwards compatibility with old sequence emulation implementation
+     * (clean up the dupes)
+     *
+     * @param string $seqname  the sequence name to clean up
+     *
+     * @return bool  true on success.  A DB_Error object on failure.
+     *
+     * @access private
+     */
+    function _BCsequence($seqname)
+    {
+        // Obtain a user-level lock... this will release any previous
+        // application locks, but unlike LOCK TABLES, it does not abort
+        // the current transaction and is much less frequently used.
+        $result = $this->getOne("SELECT GET_LOCK('${seqname}_lock',10)");
+        if (DB::isError($result)) {
+            return $result;
+        }
+        if ($result == 0) {
+            // Failed to get the lock, can't do the conversion, bail
+            // with a DB_ERROR_NOT_LOCKED error
+            return $this->mysqliRaiseError(DB_ERROR_NOT_LOCKED);
+        }
+
+        $highest_id = $this->getOne("SELECT MAX(id) FROM ${seqname}");
+        if (DB::isError($highest_id)) {
+            return $highest_id;
+        }
+
+        // This should kill all rows except the highest
+        // We should probably do something if $highest_id isn't
+        // numeric, but I'm at a loss as how to handle that...
+        $result = $this->query('DELETE FROM ' . $seqname
+                               . " WHERE id <> $highest_id");
+        if (DB::isError($result)) {
+            return $result;
+        }
+
+        // If another thread has been waiting for this lock,
+        // it will go thru the above procedure, but will have no
+        // real effect
+        $result = $this->getOne("SELECT RELEASE_LOCK('${seqname}_lock')");
+        if (DB::isError($result)) {
+            return $result;
+        }
+        return true;
+    }
+
+    // }}}
+    // {{{ quoteIdentifier()
+
+    /**
+     * Quotes a string so it can be safely used as a table or column name
+     *
+     * MySQL can't handle the backtick character (<kbd>`</kbd>) in
+     * table or column names.
+     *
+     * @param string $str  identifier name to be quoted
+     *
+     * @return string  quoted identifier string
+     *
+     * @see DB_common::quoteIdentifier()
+     * @since Method available since Release 1.6.0
+     */
+    function quoteIdentifier($str)
+    {
+        return '`' . $str . '`';
+    }
+
+    // }}}
+    // {{{ escapeSimple()
+
+    /**
+     * Escapes a string according to the current DBMS's standards
+     *
+     * @param string $str  the string to be escaped
+     *
+     * @return string  the escaped string
+     *
+     * @see DB_common::quoteSmart()
+     * @since Method available since Release 1.6.0
+     */
+    function escapeSimple($str)
+    {
+        return @mysqli_real_escape_string($this->connection, $str);
+    }
+
+    // }}}
+    // {{{ modifyLimitQuery()
+
+    /**
+     * Adds LIMIT clauses to a query string according to current DBMS standards
+     *
+     * @param string $query   the query to modify
+     * @param int    $from    the row to start to fetching (0 = the first row)
+     * @param int    $count   the numbers of rows to fetch
+     * @param mixed  $params  array, string or numeric data to be used in
+     *                         execution of the statement.  Quantity of items
+     *                         passed must match quantity of placeholders in
+     *                         query:  meaning 1 placeholder for non-array
+     *                         parameters or 1 placeholder per array element.
+     *
+     * @return string  the query string with LIMIT clauses added
+     *
+     * @access protected
+     */
+    function modifyLimitQuery($query, $from, $count, $params = array())
+    {
+        if (DB::isManip($query)) {
+            return $query . " LIMIT $count";
+        } else {
+            return $query . " LIMIT $from, $count";
+        }
+    }
+
+    // }}}
+    // {{{ mysqliRaiseError()
+
+    /**
+     * Produces a DB_Error object regarding the current problem
+     *
+     * @param int $errno  if the error is being manually raised pass a
+     *                     DB_ERROR* constant here.  If this isn't passed
+     *                     the error information gathered from the DBMS.
+     *
+     * @return object  the DB_Error object
+     *
+     * @see DB_common::raiseError(),
+     *      DB_mysqli::errorNative(), DB_common::errorCode()
+     */
+    function mysqliRaiseError($errno = null)
+    {
+        if ($errno === null) {
+            if ($this->options['portability'] & DB_PORTABILITY_ERRORS) {
+                $this->errorcode_map[1022] = DB_ERROR_CONSTRAINT;
+                $this->errorcode_map[1048] = DB_ERROR_CONSTRAINT_NOT_NULL;
+                $this->errorcode_map[1062] = DB_ERROR_CONSTRAINT;
+            } else {
+                // Doing this in case mode changes during runtime.
+                $this->errorcode_map[1022] = DB_ERROR_ALREADY_EXISTS;
+                $this->errorcode_map[1048] = DB_ERROR_CONSTRAINT;
+                $this->errorcode_map[1062] = DB_ERROR_ALREADY_EXISTS;
+            }
+            $errno = $this->errorCode(mysqli_errno($this->connection));
+        }
+        return $this->raiseError($errno, null, null, null,
+                                 @mysqli_errno($this->connection) . ' ** ' .
+                                 @mysqli_error($this->connection));
+    }
+
+    // }}}
+    // {{{ errorNative()
+
+    /**
+     * Gets the DBMS' native error code produced by the last query
+     *
+     * @return int  the DBMS' error code
+     */
+    function errorNative()
+    {
+        return @mysqli_errno($this->connection);
+    }
+
+    // }}}
+    // {{{ tableInfo()
+
+    /**
+     * Returns information about a table or a result set
+     *
+     * @param object|string  $result  DB_result object from a query or a
+     *                                 string containing the name of a table.
+     *                                 While this also accepts a query result
+     *                                 resource identifier, this behavior is
+     *                                 deprecated.
+     * @param int            $mode    a valid tableInfo mode
+     *
+     * @return array  an associative array with the information requested.
+     *                 A DB_Error object on failure.
+     *
+     * @see DB_common::setOption()
+     */
+    function tableInfo($result, $mode = null)
+    {
+        if (is_string($result)) {
+            /*
+             * Probably received a table name.
+             * Create a result resource identifier.
+             */
+            $id = @mysqli_query($this->connection,
+                                "SELECT * FROM $result LIMIT 0");
+            $got_string = true;
+        } elseif (isset($result->result)) {
+            /*
+             * Probably received a result object.
+             * Extract the result resource identifier.
+             */
+            $id = $result->result;
+            $got_string = false;
+        } else {
+            /*
+             * Probably received a result resource identifier.
+             * Copy it.
+             * Deprecated.  Here for compatibility only.
+             */
+            $id = $result;
+            $got_string = false;
+        }
+
+        if (!is_a($id, 'mysqli_result')) {
+            return $this->mysqliRaiseError(DB_ERROR_NEED_MORE_DATA);
+        }
+
+        if ($this->options['portability'] & DB_PORTABILITY_LOWERCASE) {
+            $case_func = 'strtolower';
+        } else {
+            $case_func = 'strval';
+        }
+
+        $count = @mysqli_num_fields($id);
+        $res   = array();
+
+        if ($mode) {
+            $res['num_fields'] = $count;
+        }
+
+        for ($i = 0; $i < $count; $i++) {
+            $tmp = @mysqli_fetch_field($id);
+
+            $flags = '';
+            foreach ($this->mysqli_flags as $const => $means) {
+                if ($tmp->flags & $const) {
+                    $flags .= $means . ' ';
+                }
+            }
+            if ($tmp->def) {
+                $flags .= 'default_' . rawurlencode($tmp->def);
+            }
+            $flags = trim($flags);
+
+            $res[$i] = array(
+                'table' => $case_func($tmp->table),
+                'name'  => $case_func($tmp->name),
+                'type'  => isset($this->mysqli_types[$tmp->type])
+                                    ? $this->mysqli_types[$tmp->type]
+                                    : 'unknown',
+                'len'   => $tmp->max_length,
+                'flags' => $flags,
+            );
+
+            if ($mode & DB_TABLEINFO_ORDER) {
+                $res['order'][$res[$i]['name']] = $i;
+            }
+            if ($mode & DB_TABLEINFO_ORDERTABLE) {
+                $res['ordertable'][$res[$i]['table']][$res[$i]['name']] = $i;
+            }
+        }
+
+        // free the result only if we were called on a table
+        if ($got_string) {
+            @mysqli_free_result($id);
+        }
+        return $res;
+    }
+
+    // }}}
+    // {{{ getSpecialQuery()
+
+    /**
+     * Obtains the query string needed for listing a given type of objects
+     *
+     * @param string $type  the kind of objects you want to retrieve
+     *
+     * @return string  the SQL query string or null if the driver doesn't
+     *                  support the object type requested
+     *
+     * @access protected
+     * @see DB_common::getListOf()
+     */
+    function getSpecialQuery($type)
+    {
+        switch ($type) {
+            case 'tables':
+                return 'SHOW TABLES';
+            case 'users':
+                return 'SELECT DISTINCT User FROM mysql.user';
+            case 'databases':
+                return 'SHOW DATABASES';
+            default:
+                return null;
+        }
+    }
+
+    // }}}
+
+}
+
+/*
+ * Local variables:
+ * tab-width: 4
+ * c-basic-offset: 4
+ * End:
+ */
+
+?>