* OracleInstaller now also supports installation with (requested by Tim):

[mediawiki.git] / includes / db / DatabaseOracle.php

<?php
/**
 * This is the Oracle database abstraction layer.
 *
 * @file
 * @ingroup Database
 */

/**
 * The oci8 extension is fairly weak and doesn't support oci_num_rows, among
 * other things.  We use a wrapper class to handle that and other
 * Oracle-specific bits, like converting column names back to lowercase.
 * @ingroup Database
 */
class ORAResult {
        private $rows;
        private $cursor;
        private $nrows;
        
        private $columns = array();

        private function array_unique_md( $array_in ) {
                $array_out = array();
                $array_hashes = array();

                foreach ( $array_in as $item ) {
                        $hash = md5( serialize( $item ) );
                        if ( !isset( $array_hashes[$hash] ) ) {
                                $array_hashes[$hash] = $hash;
                                $array_out[] = $item;
                        }
                }

                return $array_out;
        }

        function __construct( &$db, $stmt, $unique = false ) {
                $this->db =& $db;

                if ( ( $this->nrows = oci_fetch_all( $stmt, $this->rows, 0, - 1, OCI_FETCHSTATEMENT_BY_ROW | OCI_NUM ) ) === false ) {
                        $e = oci_error( $stmt );
                        $db->reportQueryError( $e['message'], $e['code'], '', __METHOD__ );
                        $this->free();
                        return;
                }

                if ( $unique ) {
                        $this->rows = $this->array_unique_md( $this->rows );
                        $this->nrows = count( $this->rows );
                }

                if ($this->nrows > 0) {
                        foreach ( $this->rows[0] as $k => $v ) {
                                $this->columns[$k] = strtolower( oci_field_name( $stmt, $k + 1 ) );
                        }
                }

                $this->cursor = 0;
                oci_free_statement( $stmt );
        }

        public function free() {
                unset($this->db);
        }

        public function seek( $row ) {
                $this->cursor = min( $row, $this->nrows );
        }

        public function numRows() {
                return $this->nrows;
        }

        public function numFields() {
                return count($this->columns);
        }

        public function fetchObject() {
                if ( $this->cursor >= $this->nrows ) {
                        return false;
                }
                $row = $this->rows[$this->cursor++];
                $ret = new stdClass();
                foreach ( $row as $k => $v ) {
                        $lc = $this->columns[$k];
                        $ret->$lc = $v;
                }

                return $ret;
        }

        public function fetchRow() {
                if ( $this->cursor >= $this->nrows ) {
                        return false;
                }

                $row = $this->rows[$this->cursor++];
                $ret = array();
                foreach ( $row as $k => $v ) {
                        $lc = $this->columns[$k];
                        $ret[$lc] = $v;
                        $ret[$k] = $v;
                }
                return $ret;
        }
}

/**
 * Utility class.
 * @ingroup Database
 */
class ORAField implements Field {
        private $name, $tablename, $default, $max_length, $nullable,
                $is_pk, $is_unique, $is_multiple, $is_key, $type;

        function __construct( $info ) {
                $this->name = $info['column_name'];
                $this->tablename = $info['table_name'];
                $this->default = $info['data_default'];
                $this->max_length = $info['data_length'];
                $this->nullable = $info['not_null'];
                $this->is_pk = isset( $info['prim'] ) && $info['prim'] == 1 ? 1 : 0;
                $this->is_unique = isset( $info['uniq'] ) && $info['uniq'] == 1 ? 1 : 0;
                $this->is_multiple = isset( $info['nonuniq'] ) && $info['nonuniq'] == 1 ? 1 : 0;
                $this->is_key = ( $this->is_pk || $this->is_unique || $this->is_multiple );
                $this->type = $info['data_type'];
        }

        function name() {
                return $this->name;
        }

        function tableName() {
                return $this->tablename;
        }

        function defaultValue() {
                return $this->default;
        }

        function maxLength() {
                return $this->max_length;
        }

        function isNullable() {
                return $this->nullable;
        }

        function isKey() {
                return $this->is_key;
        }

        function isMultipleKey() {
                return $this->is_multiple;
        }

        function type() {
                return $this->type;
        }
}

/**
 * @ingroup Database
 */
class DatabaseOracle extends DatabaseBase {
        var $mInsertId = null;
        var $mLastResult = null;
        var $numeric_version = null;
        var $lastResult = null;
        var $cursor = 0;
        var $mAffectedRows;

        var $ignore_DUP_VAL_ON_INDEX = false;
        var $sequenceData = null;

        var $defaultCharset = 'AL32UTF8';

        var $mFieldInfoCache = array();

        function __construct( $server = false, $user = false, $password = false, $dbName = false,
                $flags = 0, $tablePrefix = 'get from global' )
        {
                $tablePrefix = $tablePrefix == 'get from global' ? $tablePrefix : strtoupper( $tablePrefix );
                parent::__construct( $server, $user, $password, $dbName, $flags, $tablePrefix );
                wfRunHooks( 'DatabaseOraclePostInit', array( $this ) );
        }

        function getType() {
                return 'oracle';
        }

        function cascadingDeletes() {
                return true;
        }
        function cleanupTriggers() {
                return true;
        }
        function strictIPs() {
                return true;
        }
        function realTimestamps() {
                return true;
        }
        function implicitGroupby() {
                return false;
        }
        function implicitOrderby() {
                return false;
        }
        function searchableIPs() {
                return true;
        }

        /**
         * Usually aborts on failure
         */
        function open( $server, $user, $password, $dbName ) {
                if ( !function_exists( 'oci_connect' ) ) {
                        throw new DBConnectionError( $this, "Oracle functions missing, have you compiled PHP with the --with-oci8 option?\n (Note: if you recently installed PHP, you may need to restart your webserver and database)\n" );
                }

                $this->close();
                $this->mUser = $user;
                $this->mPassword = $password;
                // changed internal variables functions
                // mServer now holds the TNS endpoint
                // mDBname is schema name if different from username
                if ( !$server ) {
                        // backward compatibillity (server used to be null and TNS was supplied in dbname)
                        $this->mServer = $dbName;
                        $this->mDBname = $user;
                } else {
                        $this->mServer = $server;
                        if ( !$dbName ) {
                                $this->mDBname = $user;
                        } else {        
                                $this->mDBname = $dbName;
                        }
                }

                if ( !strlen( $user ) ) { # e.g. the class is being loaded
                        return;
                }

                $session_mode = $this->mFlags & DBO_SYSDBA ? OCI_SYSDBA : OCI_DEFAULT;
                if ( $this->mFlags & DBO_DEFAULT ) {
                        $this->mConn = @oci_new_connect( $this->mUser, $this->mPassword, $this->mServer, $this->defaultCharset, $session_mode );
                } else {
                        $this->mConn = @oci_connect( $this->mUser, $this->mPassword, $this->mServer, $this->defaultCharset, $session_mode );
                }

                if ( $this->mUser != $this->mDBname ) {
                        //change current schema in session
                        $this->selectDB( $this->mDBname );
                }

                if ( !$this->mConn ) {
                        throw new DBConnectionError( $this, $this->lastError() );
                }

                $this->mOpened = true;

                # removed putenv calls because they interfere with the system globaly
                $this->doQuery( 'ALTER SESSION SET NLS_TIMESTAMP_FORMAT=\'DD-MM-YYYY HH24:MI:SS.FF6\'' );
                $this->doQuery( 'ALTER SESSION SET NLS_TIMESTAMP_TZ_FORMAT=\'DD-MM-YYYY HH24:MI:SS.FF6\'' );
                return $this->mConn;
        }

        /**
         * Closes a database connection, if it is open
         * Returns success, true if already closed
         */
        function close() {
                $this->mOpened = false;
                if ( $this->mConn ) {
                        return oci_close( $this->mConn );
                } else {
                        return true;
                }
        }

        function execFlags() {
                return $this->mTrxLevel ? OCI_DEFAULT : OCI_COMMIT_ON_SUCCESS;
        }

        function doQuery( $sql ) {
                wfDebug( "SQL: [$sql]\n" );
                if ( !mb_check_encoding( $sql ) ) {
                        throw new MWException( "SQL encoding is invalid\n$sql" );
                }

                // handle some oracle specifics
                // remove AS column/table/subquery namings
                if( !$this->getFlag( DBO_DDLMODE ) ) {
                        $sql = preg_replace( '/ as /i', ' ', $sql );
                }

                // Oracle has issues with UNION clause if the statement includes LOB fields
                // So we do a UNION ALL and then filter the results array with array_unique
                $union_unique = ( preg_match( '/\/\* UNION_UNIQUE \*\/ /', $sql ) != 0 );
                // EXPLAIN syntax in Oracle is EXPLAIN PLAN FOR and it return nothing
                // you have to select data from plan table after explain
                $explain_id = date( 'dmYHis' );

                $sql = preg_replace( '/^EXPLAIN /', 'EXPLAIN PLAN SET STATEMENT_ID = \'' . $explain_id . '\' FOR', $sql, 1, $explain_count );

                wfSuppressWarnings();

                if ( ( $this->mLastResult = $stmt = oci_parse( $this->mConn, $sql ) ) === false ) {
                        $e = oci_error( $this->mConn );
                        $this->reportQueryError( $e['message'], $e['code'], $sql, __METHOD__ );
                        return false;
                }

                if ( !oci_execute( $stmt, $this->execFlags() ) ) {
                        $e = oci_error( $stmt );
                        if ( !$this->ignore_DUP_VAL_ON_INDEX || $e['code'] != '1' ) {
                                $this->reportQueryError( $e['message'], $e['code'], $sql, __METHOD__ );
                                return false;
                        }
                }

                wfRestoreWarnings();

                if ( $explain_count > 0 ) {
                        return $this->doQuery( 'SELECT id, cardinality "ROWS" FROM plan_table WHERE statement_id = \'' . $explain_id . '\'' );
                } elseif ( oci_statement_type( $stmt ) == 'SELECT' ) {
                        return new ORAResult( $this, $stmt, $union_unique );
                } else {
                        $this->mAffectedRows = oci_num_rows( $stmt );
                        return true;
                }
        }

        function queryIgnore( $sql, $fname = '' ) {
                return $this->query( $sql, $fname, true );
        }

        function freeResult( $res ) {
                if ( $res instanceof ResultWrapper ) {
                        $res = $res->result;
                }
                
                $res->free();
        }

        function fetchObject( $res ) {
                if ( $res instanceof ResultWrapper ) {
                        $res = $res->result;
                }
                
                return $res->fetchObject();
        }

        function fetchRow( $res ) {
                if ( $res instanceof ResultWrapper ) {
                        $res = $res->result;
                }

                return $res->fetchRow();
        }

        function numRows( $res ) {
                if ( $res instanceof ResultWrapper ) {
                        $res = $res->result;
                }

                return $res->numRows();
        }

        function numFields( $res ) {
                if ( $res instanceof ResultWrapper ) {
                        $res = $res->result;
                }

                return $res->numFields();
        }

        function fieldName( $stmt, $n ) {
                return oci_field_name( $stmt, $n );
        }

        /**
         * This must be called after nextSequenceVal
         */
        function insertId() {
                return $this->mInsertId;
        }

        function dataSeek( $res, $row ) {
                if ( $res instanceof ORAResult ) {
                        $res->seek( $row );
                } else {
                        $res->result->seek( $row );
                }
        }

        function lastError() {
                if ( $this->mConn === false ) {
                        $e = oci_error();
                } else {
                        $e = oci_error( $this->mConn );
                }
                return $e['message'];
        }

        function lastErrno() {
                if ( $this->mConn === false ) {
                        $e = oci_error();
                } else {
                        $e = oci_error( $this->mConn );
                }
                return $e['code'];
        }

        function affectedRows() {
                return $this->mAffectedRows;
        }

        /**
         * Returns information about an index
         * If errors are explicitly ignored, returns NULL on failure
         */
        function indexInfo( $table, $index, $fname = 'DatabaseOracle::indexExists' ) {
                return false;
        }

        function indexUnique( $table, $index, $fname = 'DatabaseOracle::indexUnique' ) {
                return false;
        }

        function insert( $table, $a, $fname = 'DatabaseOracle::insert', $options = array() ) {
                if ( !count( $a ) ) {
                        return true;
                }

                if ( !is_array( $options ) ) {
                        $options = array( $options );
                }

                if ( in_array( 'IGNORE', $options ) ) {
                        $this->ignore_DUP_VAL_ON_INDEX = true;
                }

                if ( !is_array( reset( $a ) ) ) {
                        $a = array( $a );
                }

                foreach ( $a as &$row ) {
                        $this->insertOneRow( $table, $row, $fname );
                }
                $retVal = true;

                if ( in_array( 'IGNORE', $options ) ) {
                        $this->ignore_DUP_VAL_ON_INDEX = false;
                }

                return $retVal;
        }

        private function fieldBindStatement ( $table, $col, &$val, $includeCol = false ) {
                $col_info = $this->fieldInfoMulti( $table, $col );
                $col_type = $col_info != false ? $col_info->type() : 'CONSTANT';
                
                $bind = '';
                if ( is_numeric( $col ) ) {
                        $bind = $val;
                        $val = null;
                        return $bind; 
                } else if ( $includeCol ) {
                        $bind = "$col = ";
                }
                
                if ( $val == '' && $val !== 0 && $col_type != 'BLOB' && $col_type != 'CLOB' ) {
                        $val = null;
                }

                if ( $val === null ) {
                        if ( $col_info != false && $col_info->isNullable() == 0 && $col_info->defaultValue() != null ) {
                                $bind .= 'DEFAULT';
                        } else {
                                $bind .= 'NULL';
                        }
                } else {
                        $bind .= ':' . $col;
                }
                
                return $bind;
        }

        private function insertOneRow( $table, $row, $fname ) {
                global $wgContLang;

                $table = $this->tableName( $table );
                // "INSERT INTO tables (a, b, c)"
                $sql = "INSERT INTO " . $table . " (" . join( ',', array_keys( $row ) ) . ')';
                $sql .= " VALUES (";

                // for each value, append ":key"
                $first = true;
                foreach ( $row as $col => &$val ) {
                        if ( !$first ) {
                                $sql .= ', ';
                        } else {
                                $first = false;
                        }
                        
                        $sql .= $this->fieldBindStatement( $table, $col, $val );
                }
                $sql .= ')';

                if ( ( $this->mLastResult = $stmt = oci_parse( $this->mConn, $sql ) ) === false ) {
                        $e = oci_error( $this->mConn );
                        $this->reportQueryError( $e['message'], $e['code'], $sql, __METHOD__ );
                        return false;
                }
                foreach ( $row as $col => &$val ) {
                        $col_info = $this->fieldInfoMulti( $table, $col );
                        $col_type = $col_info != false ? $col_info->type() : 'CONSTANT';

                        if ( $val === null ) {
                                // do nothing ... null was inserted in statement creation
                        } elseif ( $col_type != 'BLOB' && $col_type != 'CLOB' ) {
                                if ( is_object( $val ) ) {
                                        $val = $val->fetch();
                                }

                                if ( preg_match( '/^timestamp.*/i', $col_type ) == 1 && strtolower( $val ) == 'infinity' ) {
                                        $val = '31-12-2030 12:00:00.000000';
                                }

                                $val = ( $wgContLang != null ) ? $wgContLang->checkTitleEncoding( $val ) : $val;
                                if ( oci_bind_by_name( $stmt, ":$col", $val ) === false ) {
                                        $e = oci_error( $stmt );
                                        $this->reportQueryError( $e['message'], $e['code'], $sql, __METHOD__ );
                                        return false;
                                }
                        } else {
                                if ( ( $lob[$col] = oci_new_descriptor( $this->mConn, OCI_D_LOB ) ) === false ) {
                                        $e = oci_error( $stmt );
                                        throw new DBUnexpectedError( $this, "Cannot create LOB descriptor: " . $e['message'] );
                                }

                                if ( is_object( $val ) ) {
                                        $val = $val->fetch();
                                }

                                if ( $col_type == 'BLOB' ) {
                                        $lob[$col]->writeTemporary( $val, OCI_TEMP_BLOB );
                                        oci_bind_by_name( $stmt, ":$col", $lob[$col], - 1, OCI_B_BLOB );
                                } else {
                                        $lob[$col]->writeTemporary( $val, OCI_TEMP_CLOB );
                                        oci_bind_by_name( $stmt, ":$col", $lob[$col], - 1, OCI_B_CLOB );
                                }
                        }
                }

                wfSuppressWarnings();

                if ( oci_execute( $stmt, OCI_DEFAULT ) === false ) {
                        $e = oci_error( $stmt );
                        if ( !$this->ignore_DUP_VAL_ON_INDEX || $e['code'] != '1' ) {
                                $this->reportQueryError( $e['message'], $e['code'], $sql, __METHOD__ );
                                return false;
                        } else {
                                $this->mAffectedRows = oci_num_rows( $stmt );
                        }
                } else {
                        $this->mAffectedRows = oci_num_rows( $stmt );
                }

                wfRestoreWarnings();

                if ( isset( $lob ) ) {
                        foreach ( $lob as $lob_v ) {
                                $lob_v->free();
                        }
                }

                if ( !$this->mTrxLevel ) {
                        oci_commit( $this->mConn );
                }

                oci_free_statement( $stmt );
        }

        function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'DatabaseOracle::insertSelect',
                $insertOptions = array(), $selectOptions = array() )
        {
                $destTable = $this->tableName( $destTable );
                if ( !is_array( $selectOptions ) ) {
                        $selectOptions = array( $selectOptions );
                }
                list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
                if ( is_array( $srcTable ) ) {
                        $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
                } else {
                        $srcTable = $this->tableName( $srcTable );
                }

                if ( ( $sequenceData = $this->getSequenceData( $destTable ) ) !== false &&
                                !isset( $varMap[$sequenceData['column']] ) )
                {
                        $varMap[$sequenceData['column']] = 'GET_SEQUENCE_VALUE(\'' . $sequenceData['sequence'] . '\')';
                }

                // count-alias subselect fields to avoid abigious definition errors
                $i = 0;
                foreach ( $varMap as &$val ) {
                        $val = $val . ' field' . ( $i++ );
                }

                $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
                        " SELECT $startOpts " . implode( ',', $varMap ) .
                        " FROM $srcTable $useIndex ";
                if ( $conds != '*' ) {
                        $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
                }
                $sql .= " $tailOpts";

                if ( in_array( 'IGNORE', $insertOptions ) ) {
                        $this->ignore_DUP_VAL_ON_INDEX = true;
                }

                $retval = $this->query( $sql, $fname );

                if ( in_array( 'IGNORE', $insertOptions ) ) {
                        $this->ignore_DUP_VAL_ON_INDEX = false;
                }

                return $retval;
        }

        function tableName( $name ) {
                global $wgSharedDB, $wgSharedPrefix, $wgSharedTables;
                /*
                Replace reserved words with better ones
                Using uppercase because that's the only way Oracle can handle
                quoted tablenames
                */
                switch( $name ) {
                        case 'user':
                                $name = 'MWUSER';
                                break;
                        case 'text':
                                $name = 'PAGECONTENT';
                                break;
                }

                /*
                        The rest of procedure is equal to generic Databse class
                        except for the quoting style
                */
                if ( $name[0] == '"' && substr( $name, - 1, 1 ) == '"' ) {
                        return $name;
                }
                if ( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) {
                        return $name;
                }
                $dbDetails = array_reverse( explode( '.', $name, 2 ) );
                if ( isset( $dbDetails[1] ) ) {
                        @list( $table, $database ) = $dbDetails;
                } else {
                        @list( $table ) = $dbDetails;
                }

                $prefix = $this->mTablePrefix;

                if ( isset( $database ) ) {
                        $table = ( $table[0] == '`' ? $table : "`{$table}`" );
                }

                if ( !isset( $database ) && isset( $wgSharedDB ) && $table[0] != '"'
                        && isset( $wgSharedTables )
                        && is_array( $wgSharedTables )
                        && in_array( $table, $wgSharedTables )
                ) {
                        $database = $wgSharedDB;
                        $prefix   = isset( $wgSharedPrefix ) ? $wgSharedPrefix : $prefix;
                }

                if ( isset( $database ) ) {
                        $database = ( $database[0] == '"' ? $database : "\"{$database}\"" );
                }
                $table = ( $table[0] == '"') ? $table : "\"{$prefix}{$table}\"" ;

                $tableName = ( isset( $database ) ? "{$database}.{$table}" : "{$table}" );

                return strtoupper( $tableName );
        }

        /**
         * Return the next in a sequence, save the value for retrieval via insertId()
         */
        function nextSequenceValue( $seqName ) {
                $res = $this->query( "SELECT $seqName.nextval FROM dual" );
                $row = $this->fetchRow( $res );
                $this->mInsertId = $row[0];
                return $this->mInsertId;
        }

        /**
         * Return sequence_name if table has a sequence
         */
        private function getSequenceData( $table ) {
                if ( $this->sequenceData == null ) {
                        $result = $this->doQuery( 'SELECT lower(us.sequence_name), lower(utc.table_name), lower(utc.column_name) from user_sequences us, user_tab_columns utc where us.sequence_name = utc.table_name||\'_\'||utc.column_name||\'_SEQ\'' );

                        while ( ( $row = $result->fetchRow() ) !== false ) {
                                $this->sequenceData[$this->tableName( $row[1] )] = array(
                                        'sequence' => $row[0],
                                        'column' => $row[2]
                                );
                        }
                }

                return ( isset( $this->sequenceData[$table] ) ) ? $this->sequenceData[$table] : false;
        }

        /**
         * REPLACE query wrapper
         * Oracle simulates this with a DELETE followed by INSERT
         * $row is the row to insert, an associative array
         * $uniqueIndexes is an array of indexes. Each element may be either a
         * field name or an array of field names
         *
         * It may be more efficient to leave off unique indexes which are unlikely to collide.
         * However if you do this, you run the risk of encountering errors which wouldn't have
         * occurred in MySQL.
         *
         * @param $table String: table name
         * @param $uniqueIndexes Array: array of indexes. Each element may be
         *                       either a field name or an array of field names
         * @param $rows Array: rows to insert to $table
         * @param $fname String: function name, you can use __METHOD__ here
         */
        function replace( $table, $uniqueIndexes, $rows, $fname = 'DatabaseOracle::replace' ) {
                $table = $this->tableName( $table );

                if ( count( $rows ) == 0 ) {
                        return;
                }

                # Single row case
                if ( !is_array( reset( $rows ) ) ) {
                        $rows = array( $rows );
                }

                $sequenceData = $this->getSequenceData( $table );

                foreach ( $rows as $row ) {
                        # Delete rows which collide
                        if ( $uniqueIndexes ) {
                                $condsDelete = array();
                                foreach ( $uniqueIndexes as $index ) {
                                        $condsDelete[$index] = $row[$index];
                                }
                                if ( count( $condsDelete ) > 0 ) {
                                        $this->delete( $table, $condsDelete, $fname );
                                }
                        }

                        if ( $sequenceData !== false && !isset( $row[$sequenceData['column']] ) ) {
                                $row[$sequenceData['column']] = $this->nextSequenceValue( $sequenceData['sequence'] );
                        }

                        # Now insert the row
                        $this->insert( $table, $row, $fname );
                }
        }

        # DELETE where the condition is a join
        function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'DatabaseOracle::deleteJoin' ) {
                if ( !$conds ) {
                        throw new DBUnexpectedError( $this, 'DatabaseOracle::deleteJoin() called with empty $conds' );
                }

                $delTable = $this->tableName( $delTable );
                $joinTable = $this->tableName( $joinTable );
                $sql = "DELETE FROM $delTable WHERE $delVar IN (SELECT $joinVar FROM $joinTable ";
                if ( $conds != '*' ) {
                        $sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
                }
                $sql .= ')';

                $this->query( $sql, $fname );
        }

        # Returns the size of a text field, or -1 for "unlimited"
        function textFieldSize( $table, $field ) {
                $fieldInfoData = $this->fieldInfo( $table, $field );
                return $fieldInfoData->maxLength();
        }

        function limitResult( $sql, $limit, $offset = false ) {
                if ( $offset === false ) {
                        $offset = 0;
                }
                return "SELECT * FROM ($sql) WHERE rownum >= (1 + $offset) AND rownum < (1 + $limit + $offset)";
        }

        function encodeBlob( $b ) {
                return new Blob( $b );
        }

        function decodeBlob( $b ) {
                if ( $b instanceof Blob ) {
                        $b = $b->fetch();
                }
                return $b;
        }

        function unionQueries( $sqls, $all ) {
                $glue = ' UNION ALL ';
                return 'SELECT * ' . ( $all ? '':'/* UNION_UNIQUE */ ' ) . 'FROM (' . implode( $glue, $sqls ) . ')' ;
        }

        function wasDeadlock() {
                return $this->lastErrno() == 'OCI-00060';
        }

        function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = 'DatabaseOracle::duplicateTableStructure' ) {
                global $wgDBprefix;
                
                $temporary = $temporary ? 'TRUE' : 'FALSE';

                $newName = trim( strtoupper( $newName ), '"');
                $oldName = trim( strtoupper( $oldName ), '"');

                $tabName = substr( $newName, strlen( $wgDBprefix ) );
                $oldPrefix = substr( $oldName, 0, strlen( $oldName ) - strlen( $tabName ) );

                return $this->doQuery( 'BEGIN DUPLICATE_TABLE(\'' . $tabName . '\', \'' . $oldPrefix . '\', \'' . strtoupper( $wgDBprefix ) . '\', ' . $temporary . '); END;' );
        }

        function listTables( $prefix = null, $fname = 'DatabaseOracle::listTables' ) {
                $listWhere = '';
                if (!empty($prefix)) {
                        $listWhere = ' AND table_name LIKE \''.strtoupper($prefix).'%\'';
                }
                
                $result = $this->doQuery( "SELECT table_name FROM user_tables WHERE table_name NOT LIKE '%!_IDX$_' ESCAPE '!' $listWhere" );

                // dirty code ... i know
                $endArray = array();
                $endArray[] = $prefix.'MWUSER';
                $endArray[] = $prefix.'PAGE';
                $endArray[] = $prefix.'IMAGE';
                $fixedOrderTabs = $endArray;
                while (($row = $result->fetchRow()) !== false) {
                        if (!in_array($row['table_name'], $fixedOrderTabs))
                                $endArray[] = $row['table_name'];
                }

                return $endArray;
        }

        public function dropTable( $tableName, $fName = 'DatabaseOracle::dropTable' ) {
                $tableName = $this->tableName($tableName);
                if( !$this->tableExists( $tableName ) ) {
                        return false;
                }
                
                return $this->doQuery( "DROP TABLE $tableName CASCADE CONSTRAINTS PURGE" );
        }

        function timestamp( $ts = 0 ) {
                return wfTimestamp( TS_ORACLE, $ts );
        }

        /**
         * Return aggregated value function call
         */
        function aggregateValue ( $valuedata, $valuename = 'value' ) {
                return $valuedata;
        }

        function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
                # Ignore errors during error handling to avoid infinite
                # recursion
                $ignore = $this->ignoreErrors( true );
                ++$this->mErrorCount;

                if ( $ignore || $tempIgnore ) {
                        wfDebug( "SQL ERROR (ignored): $error\n" );
                        $this->ignoreErrors( $ignore );
                } else {
                        throw new DBQueryError( $this, $error, $errno, $sql, $fname );
                }
        }

        /**
         * @return string wikitext of a link to the server software's web site
         */
        public static function getSoftwareLink() {
                return '[http://www.oracle.com/ Oracle]';
        }

        /**
         * @return string Version information from the database
         */
        function getServerVersion() {
                //better version number, fallback on driver
                $rset = $this->doQuery( 'SELECT version FROM product_component_version WHERE UPPER(product) LIKE \'ORACLE DATABASE%\'' );
                if ( !( $row =  $rset->fetchRow() ) ) {
                        return oci_server_version( $this->mConn );
                } 
                return $row['version'];
        }

        /**
         * Query whether a given table exists (in the given schema, or the default mw one if not given)
         */
        function tableExists( $table ) {
                $table = trim($this->tableName($table), '"');
                $SQL = "SELECT 1 FROM user_tables WHERE table_name='$table'";
                $res = $this->doQuery( $SQL );
                if ( $res ) {
                        $count = $res->numRows();
                        $res->free();
                } else {
                        $count = 0;
                }
                return $count;
        }

        /**
         * Function translates mysql_fetch_field() functionality on ORACLE.
         * Caching is present for reducing query time.
         * For internal calls. Use fieldInfo for normal usage.
         * Returns false if the field doesn't exist
         *
         * @param $table Array
         * @param $field String
         * @return ORAField
         */
        private function fieldInfoMulti( $table, $field ) {
                $field = strtoupper( $field );
                if ( is_array( $table ) ) {
                        $table = array_map( array( &$this, 'tableName' ), $table );
                        $tableWhere = 'IN (';
                        foreach( $table as &$singleTable ) {
                                $singleTable = strtoupper( trim( $singleTable, '"' ) );
                                if ( isset( $this->mFieldInfoCache["$singleTable.$field"] ) ) {
                                        return $this->mFieldInfoCache["$singleTable.$field"];
                                }
                                $tableWhere .= '\'' . $singleTable . '\',';
                        }
                        $tableWhere = rtrim( $tableWhere, ',' ) . ')';
                } else {
                        $table = strtoupper( trim( $this->tableName( $table ), '"' ) );
                        if ( isset( $this->mFieldInfoCache["$table.$field"] ) ) {
                                return $this->mFieldInfoCache["$table.$field"];
                        }
                        $tableWhere = '= \''.$table.'\'';
                }

                $fieldInfoStmt = oci_parse( $this->mConn, 'SELECT * FROM wiki_field_info_full WHERE table_name '.$tableWhere.' and column_name = \''.$field.'\'' );
                if ( oci_execute( $fieldInfoStmt, OCI_DEFAULT ) === false ) {
                        $e = oci_error( $fieldInfoStmt );
                        $this->reportQueryError( $e['message'], $e['code'], 'fieldInfo QUERY', __METHOD__ );
                        return false;
                }
                $res = new ORAResult( $this, $fieldInfoStmt );
                if ( $res->numRows() == 0 ) {
                        if ( is_array( $table ) ) {
                                foreach( $table as &$singleTable ) {
                                        $this->mFieldInfoCache["$singleTable.$field"] = false;
                                }
                        } else {
                                $this->mFieldInfoCache["$table.$field"] = false;
                        }
                        $fieldInfoTemp = null;
                } else {
                        $fieldInfoTemp = new ORAField( $res->fetchRow() );
                        $table = $fieldInfoTemp->tableName();
                        $this->mFieldInfoCache["$table.$field"] = $fieldInfoTemp;
                }
                $res->free();
                return $fieldInfoTemp;
        }

        /**
         * @throws DBUnexpectedError
         * @param  $table
         * @param  $field
         * @return ORAField
         */
        function fieldInfo( $table, $field ) {
                if ( is_array( $table ) ) {
                        throw new DBUnexpectedError( $this, 'DatabaseOracle::fieldInfo called with table array!' );
                }
                return $this->fieldInfoMulti ($table, $field);
        }

        function begin( $fname = '' ) {
                $this->mTrxLevel = 1;
        }

        function commit( $fname = '' ) {
                oci_commit( $this->mConn );
                $this->mTrxLevel = 0;
        }

        /* Not even sure why this is used in the main codebase... */
        function limitResultForUpdate( $sql, $num ) {
                return $sql;
        }

        /* defines must comply with ^define\s*([^\s=]*)\s*=\s?'\{\$([^\}]*)\}'; */
        function sourceStream( $fp, $lineCallback = false, $resultCallback = false, $fname = 'DatabaseOracle::sourceStream' ) {
                $cmd = '';
                $done = false;
                $dollarquote = false;

                $replacements = array();

                while ( ! feof( $fp ) ) {
                        if ( $lineCallback ) {
                                call_user_func( $lineCallback );
                        }
                        $line = trim( fgets( $fp, 1024 ) );
                        $sl = strlen( $line ) - 1;

                        if ( $sl < 0 ) {
                                continue;
                        }
                        if ( '-' == $line { 0 } && '-' == $line { 1 } ) {
                                continue;
                        }

                        // Allow dollar quoting for function declarations
                        if ( substr( $line, 0, 8 ) == '/*$mw$*/' ) {
                                if ( $dollarquote ) {
                                        $dollarquote = false;
                                        $line = str_replace( '/*$mw$*/', '', $line ); // remove dollarquotes
                                        $done = true;
                                } else {
                                        $dollarquote = true;
                                }
                        } elseif ( !$dollarquote ) {
                                if ( ';' == $line { $sl } && ( $sl < 2 || ';' != $line { $sl - 1 } ) ) {
                                        $done = true;
                                        $line = substr( $line, 0, $sl );
                                }
                        }

                        if ( $cmd != '' ) {
                                $cmd .= ' ';
                        }
                        $cmd .= "$line\n";

                        if ( $done ) {
                                $cmd = str_replace( ';;', ";", $cmd );
                                if ( strtolower( substr( $cmd, 0, 6 ) ) == 'define' ) {
                                        if ( preg_match( '/^define\s*([^\s=]*)\s*=\s*\'\{\$([^\}]*)\}\'/', $cmd, $defines ) ) {
                                                $replacements[$defines[2]] = $defines[1];
                                        }
                                } else {
                                        foreach ( $replacements as $mwVar => $scVar ) {
                                                $cmd = str_replace( '&' . $scVar . '.', '`{$' . $mwVar . '}`', $cmd );
                                        }

                                        $cmd = $this->replaceVars( $cmd );
                                        $res = $this->doQuery( $cmd );
                                        if ( $resultCallback ) {
                                                call_user_func( $resultCallback, $res, $this );
                                        }

                                        if ( false === $res ) {
                                                $err = $this->lastError();
                                                return "Query \"{$cmd}\" failed with error code \"$err\".\n";
                                        }
                                }

                                $cmd = '';
                                $done = false;
                        }
                }
                return true;
        }

        function selectDB( $db ) {
                $this->mDBname = $db;
                if ( $db == null || $db == $this->mUser ) {
                        return true;
                }
                $sql = 'ALTER SESSION SET CURRENT_SCHEMA=' . strtoupper($db);
                $stmt = oci_parse( $this->mConn, $sql );
                wfSuppressWarnings();
                $success = oci_execute( $stmt );
                wfRestoreWarnings();
                if ( !$success ) {
                        $e = oci_error( $stmt );
                        if ( $e['code'] != '1435' ) {
                                $this->reportQueryError( $e['message'], $e['code'], $sql, __METHOD__ );
                        }
                        return false;
                }
                return true;
        }

        function strencode( $s ) {
                return str_replace( "'", "''", $s );
        }

        function addQuotes( $s ) {
                global $wgContLang;
                if ( isset( $wgContLang->mLoaded ) && $wgContLang->mLoaded ) {
                        $s = $wgContLang->checkTitleEncoding( $s );
                }
                return "'" . $this->strencode( $s ) . "'";
        }

        public function addIdentifierQuotes( $s ) {
                if ( !$this->mFlags & DBO_DDLMODE ) {
                        $s = '"' . str_replace( '"', '""', $s ) . '"';
                }
                return $s;
        }

        function selectRow( $table, $vars, $conds, $fname = 'DatabaseOracle::selectRow', $options = array(), $join_conds = array() ) {
                global $wgContLang;

                if ($conds != null) {
                        $conds2 = array();
                        $conds = ( !is_array( $conds ) ) ? array( $conds ) : $conds;
                        foreach ( $conds as $col => $val ) {
                                $col_info = $this->fieldInfoMulti( $table, $col );
                                $col_type = $col_info != false ? $col_info->type() : 'CONSTANT';
                                if ( $col_type == 'CLOB' ) {
                                        $conds2['TO_CHAR(' . $col . ')'] = $wgContLang->checkTitleEncoding( $val );
                                } elseif ( $col_type == 'VARCHAR2' && !mb_check_encoding( $val ) ) {
                                        $conds2[$col] = $wgContLang->checkTitleEncoding( $val );
                                } else {
                                        $conds2[$col] = $val;
                                }
                        }

                        return parent::selectRow( $table, $vars, $conds2, $fname, $options, $join_conds );
                } else {
                        return parent::selectRow( $table, $vars, $conds, $fname, $options, $join_conds );
                }
        }

        /**
         * Returns an optional USE INDEX clause to go after the table, and a
         * string to go at the end of the query
         *
         * @private
         *
         * @param $options Array: an associative array of options to be turned into
         *              an SQL query, valid keys are listed in the function.
         * @return array
         */
        function makeSelectOptions( $options ) {
                $preLimitTail = $postLimitTail = '';
                $startOpts = '';

                $noKeyOptions = array();
                foreach ( $options as $key => $option ) {
                        if ( is_numeric( $key ) ) {
                                $noKeyOptions[$option] = true;
                        }
                }

                if ( isset( $options['GROUP BY'] ) ) {
                        $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
                }
                if ( isset( $options['ORDER BY'] ) ) {
                        $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
                }

                # if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $tailOpts .= ' FOR UPDATE';
                # if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $tailOpts .= ' LOCK IN SHARE MODE';
                if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
                        $startOpts .= 'DISTINCT';
                }

                if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
                        $useIndex = $this->useIndexClause( $options['USE INDEX'] );
                } else {
                        $useIndex = '';
                }

                return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
        }

        public function delete( $table, $conds, $fname = 'DatabaseOracle::delete' ) {
                global $wgContLang;

                if ( $wgContLang != null && $conds != null && $conds != '*' ) {
                        $conds2 = array();
                        $conds = ( !is_array( $conds ) ) ? array( $conds ) : $conds;
                        foreach ( $conds as $col => $val ) {
                                $col_info = $this->fieldInfoMulti( $table, $col );
                                $col_type = $col_info != false ? $col_info->type() : 'CONSTANT';
                                if ( $col_type == 'CLOB' ) {
                                        $conds2['TO_CHAR(' . $col . ')'] = $wgContLang->checkTitleEncoding( $val );
                                } else {
                                        if ( is_array( $val ) ) {
                                                $conds2[$col] = $val;
                                                foreach ( $conds2[$col] as &$val2 ) {
                                                        $val2 = $wgContLang->checkTitleEncoding( $val2 );
                                                }
                                        } else {
                                                $conds2[$col] = $wgContLang->checkTitleEncoding( $val );
                                        }
                                }
                        }

                        return parent::delete( $table, $conds2, $fname );
                } else {
                        return parent::delete( $table, $conds, $fname );
                }
        }

        function update( $table, $values, $conds, $fname = 'DatabaseOracle::update', $options = array() ) {
                global $wgContLang;
                
                $table = $this->tableName( $table );
                $opts = $this->makeUpdateOptions( $options );
                $sql = "UPDATE $opts $table SET ";
                
                $first = true;
                foreach ( $values as $col => &$val ) {
                        $sqlSet = $this->fieldBindStatement( $table, $col, $val, true );
                        
                        if ( !$first ) {
                                $sqlSet = ', ' . $sqlSet;
                        } else {
                                $first = false;
                        }
                        $sql .= $sqlSet;
                }

                if ( $conds != '*' ) {
                        $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
                }

                if ( ( $this->mLastResult = $stmt = oci_parse( $this->mConn, $sql ) ) === false ) {
                        $e = oci_error( $this->mConn );
                        $this->reportQueryError( $e['message'], $e['code'], $sql, __METHOD__ );
                        return false;
                }
                foreach ( $values as $col => &$val ) {
                        $col_info = $this->fieldInfoMulti( $table, $col );
                        $col_type = $col_info != false ? $col_info->type() : 'CONSTANT';

                        if ( $val === null ) {
                                // do nothing ... null was inserted in statement creation
                        } elseif ( $col_type != 'BLOB' && $col_type != 'CLOB' ) {
                                if ( is_object( $val ) ) {
                                        $val = $val->getData();
                                }

                                if ( preg_match( '/^timestamp.*/i', $col_type ) == 1 && strtolower( $val ) == 'infinity' ) {
                                        $val = '31-12-2030 12:00:00.000000';
                                }

                                $val = ( $wgContLang != null ) ? $wgContLang->checkTitleEncoding( $val ) : $val;
                                if ( oci_bind_by_name( $stmt, ":$col", $val ) === false ) {
                                        $e = oci_error( $stmt );
                                        $this->reportQueryError( $e['message'], $e['code'], $sql, __METHOD__ );
                                        return false;
                                }
                        } else {
                                if ( ( $lob[$col] = oci_new_descriptor( $this->mConn, OCI_D_LOB ) ) === false ) {
                                        $e = oci_error( $stmt );
                                        throw new DBUnexpectedError( $this, "Cannot create LOB descriptor: " . $e['message'] );
                                }

                                if ( $col_type == 'BLOB' ) { 
                                        $lob[$col]->writeTemporary( $val ); 
                                        oci_bind_by_name( $stmt, ":$col", $lob[$col], - 1, SQLT_BLOB );
                                } else {
                                        $lob[$col]->writeTemporary( $val );
                                        oci_bind_by_name( $stmt, ":$col", $lob[$col], - 1, OCI_B_CLOB );
                                }
                        }
                }

                wfSuppressWarnings();

                if ( oci_execute( $stmt, OCI_DEFAULT ) === false ) {
                        $e = oci_error( $stmt );
                        if ( !$this->ignore_DUP_VAL_ON_INDEX || $e['code'] != '1' ) {
                                $this->reportQueryError( $e['message'], $e['code'], $sql, __METHOD__ );
                                return false;
                        } else {
                                $this->mAffectedRows = oci_num_rows( $stmt );
                        }
                } else {
                        $this->mAffectedRows = oci_num_rows( $stmt );
                }

                wfRestoreWarnings();

                if ( isset( $lob ) ) {
                        foreach ( $lob as $lob_v ) {
                                $lob_v->free();
                        }
                }

                if ( !$this->mTrxLevel ) {
                        oci_commit( $this->mConn );
                }

                oci_free_statement( $stmt );
        }

        function bitNot( $field ) {
                // expecting bit-fields smaller than 4bytes
                return 'BITNOT(' . $field . ')';
        }

        function bitAnd( $fieldLeft, $fieldRight ) {
                return 'BITAND(' . $fieldLeft . ', ' . $fieldRight . ')';
        }

        function bitOr( $fieldLeft, $fieldRight ) {
                return 'BITOR(' . $fieldLeft . ', ' . $fieldRight . ')';
        }

        function setFakeMaster( $enabled = true ) { }

        function getDBname() {
                return $this->mDBname;
        }

        function getServer() {
                return $this->mServer;
        }

        public function getSearchEngine() {
                return 'SearchOracle';
        }
} // end DatabaseOracle class