Proyectos de Subversion Moodle

<?php

/**

 * Firebird driver.

 *

 * Requires firebird client. Works on Windows and Unix.

 *

 * This file is part of ADOdb, a Database Abstraction Layer library for PHP.

 *

 * @package ADOdb

 * @link https://adodb.org Project's web site and documentation

 * @link https://github.com/ADOdb/ADOdb Source code and issue tracker

 *

 * The ADOdb Library is dual-licensed, released under both the BSD 3-Clause

 * and the GNU Lesser General Public Licence (LGPL) v2.1 or, at your option,

 * any later version. This means you can use it in proprietary products.

 * See the LICENSE.md file distributed with this source code for details.

 * @license BSD-3-Clause

 * @license LGPL-2.1-or-later

 *

 * @copyright 2000-2013 John Lim

 * @copyright 2014 Damien Regad, Mark Newnham and the ADOdb community

 *

 * Driver was cloned from Interbase, so there's quite a lot of duplicated code

 * @noinspection DuplicatedCode

 * @noinspection PhpUnused

 */

// security - hide paths

if (!defined('ADODB_DIR')) die();

class ADODB_firebird extends ADOConnection {

	var $databaseType = "firebird";

	var $dataProvider = "firebird";

	var $replaceQuote = "''"; // string to use to replace quotes

	var $fbird_datefmt = '%Y-%m-%d'; // For hours,mins,secs change to '%Y-%m-%d %H:%M:%S';

	var $fmtDate = "'Y-m-d'";

	var $fbird_timestampfmt = "%Y-%m-%d %H:%M:%S";

	var $fbird_timefmt = "%H:%M:%S";

	var $fmtTimeStamp = "'Y-m-d, H:i:s'";

	var $concat_operator='||';

	var $_transactionID;

	public $metaTablesSQL = "SELECT LOWER(rdb\$relation_name) FROM rdb\$relations";

	//OPN STUFF start

	var $metaColumnsSQL = "select lower(a.rdb\$field_name), a.rdb\$null_flag, a.rdb\$default_source, b.rdb\$field_length, b.rdb\$field_scale, b.rdb\$field_sub_type, b.rdb\$field_precision, b.rdb\$field_type from rdb\$relation_fields a, rdb\$fields b where a.rdb\$field_source = b.rdb\$field_name and a.rdb\$relation_name = '%s' order by a.rdb\$field_position asc";

	//OPN STUFF end

	public $_genSeqSQL = "CREATE SEQUENCE %s START WITH %s";

	public $_dropSeqSQL = "DROP SEQUENCE %s";

	var $hasGenID = true;

	var $_bindInputArray = true;

	var $sysDate = "cast('TODAY' as timestamp)";

	var $sysTimeStamp = "CURRENT_TIMESTAMP"; //"cast('NOW' as timestamp)";

	var $ansiOuter = true;

	var $hasAffectedRows = true;

	var $poorAffectedRows = false;

	var $blobEncodeType = 'C';

	/*

	* firebird custom optionally specifies the user role

	*/

	public $role = false;

	/*

	* firebird custom optionally specifies the connection buffers

	*/

	public $buffers = 0;

	/*

	* firebird custom optionally specifies database dialect

	*/

	public $dialect = 3;

	var $nameQuote = '';		/// string to use to quote identifiers and names

	function __construct()

	{

		parent::__construct();

		$this->setTransactionMode('');

	}

	/**

	 * Sets the isolation level of a transaction.

	 *

	 * The default behavior is a more practical IBASE_WAIT | IBASE_REC_VERSION | IBASE_COMMITTED

	 * instead of IBASE_DEFAULT

	 *

	 * @link https://adodb.org/dokuwiki/doku.php?id=v5:reference:connection:settransactionmode

	 *

	 * @param string $transaction_mode The transaction mode to set.

	 *

	 * @return void

	 */

	public function setTransactionMode($transaction_mode)

	{

		$this->_transmode = $transaction_mode;

		if (empty($transaction_mode)) {

			$this->_transmode = IBASE_WAIT | IBASE_REC_VERSION | IBASE_COMMITTED;

		}

	}

	/**

	 * Connect to a database.

	 *

	 * @todo add: parameter int $port, parameter string $socket

	 *

	 * @param string|null $argHostname (Optional) The host to connect to.

	 * @param string|null $argUsername (Optional) The username to connect as.

	 * @param string|null $argPassword (Optional) The password to connect with.

	 * @param string|null $argDatabasename (Optional) The name of the database to start in when connected.

	 * @param bool $persist (Optional) Whether or not to use a persistent connection.

	 *

	 * @return bool|null True if connected successfully, false if connection failed, or null if the mysqli extension

	 * isn't currently loaded.

	 */

	public function _connect($argHostname, $argUsername, $argPassword, $argDatabasename,$persist=false)

	{

		if (!function_exists('fbird_pconnect'))

			return null;

		if ($argDatabasename)

			$argHostname .= ':'.$argDatabasename;

		$fn = ($persist) ? 'fbird_pconnect':'fbird_connect';

		/*

		* Now merge in the standard connection parameters setting

		*/

		foreach ($this->connectionParameters as $options)

		{

			foreach($options as $k=>$v)

			{

				switch($k){

				case 'role':

					$this->role = $v;

					break;

				case 'dialect':

					$this->dialect = $v;

					break;

				case 'buffers':

					$this->buffers = $v;

				}

			}

		}

		if ($this->role)

			$this->_connectionID = $fn($argHostname,$argUsername,$argPassword,

					$this->charSet,$this->buffers,$this->dialect,$this->role);

		else

			$this->_connectionID = $fn($argHostname,$argUsername,$argPassword,

					$this->charSet,$this->buffers,$this->dialect);

		if ($this->dialect == 1) { // http://www.ibphoenix.com/ibp_60_del_id_ds.html

			$this->replaceQuote = "";

		}

		if ($this->_connectionID === false) {

			$this->_handleError();

			return false;

		}

		ini_set("ibase.timestampformat", $this->fbird_timestampfmt);

		ini_set("ibase.dateformat", $this->fbird_datefmt);

		ini_set("ibase.timeformat", $this->fbird_timefmt);

		return true;

	}

	/**

	 * Connect to a database with a persistent connection.

	 *

	 * @param string|null $argHostname The host to connect to.

	 * @param string|null $argUsername The username to connect as.

	 * @param string|null $argPassword The password to connect with.

	 * @param string|null $argDatabasename The name of the database to start in when connected.

	 *

	 * @return bool|null True if connected successfully, false if connection failed, or null if the mysqli extension

	 * isn't currently loaded.

	 */

	function _pconnect($argHostname, $argUsername, $argPassword, $argDatabasename)

	{

		return $this->_connect($argHostname, $argUsername, $argPassword, $argDatabasename,true);

	}

	public function metaPrimaryKeys($table,$owner_notused=false,$internalKey=false)

	{

		if ($internalKey) {

			return array('RDB$DB_KEY');

		}

		$table = strtoupper($table);

		$sql = 'SELECT S.RDB$FIELD_NAME AFIELDNAME

	FROM RDB$INDICES I JOIN RDB$INDEX_SEGMENTS S ON I.RDB$INDEX_NAME=S.RDB$INDEX_NAME

	WHERE I.RDB$RELATION_NAME=\''.$table.'\' and I.RDB$INDEX_NAME like \'RDB$PRIMARY%\'

	ORDER BY I.RDB$INDEX_NAME,S.RDB$FIELD_POSITION';

		$a = $this->GetCol($sql,false,true);

		if ($a && sizeof($a)>0) return $a;

		return false;

	}

	/**

	 * Get information about the current Firebird server.

	 *

	 * @return array

	 */

	public function serverInfo()

	{

		$arr['dialect'] = $this->dialect;

		switch($arr['dialect']) {

			case '':

			case '1':

				$s = 'Firebird Dialect 1';

				break;

			case '2':

				$s = 'Firebird Dialect 2';

				break;

			default:

			case '3':

				$s = 'Firebird Dialect 3';

				break;

		}

		$arr['version'] = ADOConnection::_findvers($s);

		$arr['description'] = $s;

		return $arr;

	}

	/**

	 * Begin a Transaction. Must be followed by CommitTrans() or RollbackTrans().

	 *

	 * @return bool true if succeeded or false if database does not support transactions

	 */

	public function beginTrans()

	{

		if ($this->transOff) return true;

		$this->transCnt += 1;

		$this->autoCommit = false;

		/*

		* We manage the transaction mode via fbird_trans

		*/

		$this->_transactionID = fbird_trans( $this->_transmode, $this->_connectionID );

		return $this->_transactionID;

	}

	/**

	 * Commits a transaction.

	 *

	 * @param bool $ok  false to rollback transaction, true to commit

	 *

	 * @return bool

	 */

	public function commitTrans($ok=true)

	{

		if (!$ok) {

			return $this->RollbackTrans();

		}

		if ($this->transOff) {

			return true;

		}

		if ($this->transCnt) {

			$this->transCnt -= 1;

		}

		$ret = false;

		$this->autoCommit = true;

		if ($this->_transactionID) {

			$ret = fbird_commit($this->_transactionID);

		}

		$this->_transactionID = false;

		return $ret;

	}

	function _affectedrows()

	{

		return fbird_affected_rows($this->_transactionID ?: $this->_connectionID);

	}

	/**

	 * Rollback a smart transaction.

	 *

	 * @link https://adodb.org/dokuwiki/doku.php?id=v5:reference:connection:rollbacktrans

	 *

	 * @return bool

	 */

	public function rollbackTrans()

	{

		if ($this->transOff)

			return true;

		if ($this->transCnt)

			$this->transCnt -= 1;

		$ret = false;

		$this->autoCommit = true;

		if ($this->_transactionID) {

			$ret = fbird_rollback($this->_transactionID);

		}

		$this->_transactionID = false;

		return $ret;

	}

	/**

	 * Get a list of indexes on the specified table.

	 *

	 * @param string $table The name of the table to get indexes for.

	 * @param bool $primary (Optional) Whether or not to include the primary key.

	 * @param bool $owner (Optional) Unused.

	 *

	 * @return array|bool An array of the indexes, or false if the query to get the indexes failed.

	 */

	public function metaIndexes($table, $primary = false, $owner = false)

	{

		// save old fetch mode

		global $ADODB_FETCH_MODE;

		$save = $ADODB_FETCH_MODE;

		$ADODB_FETCH_MODE = ADODB_FETCH_NUM;

		if ($this->fetchMode !== FALSE) {

				$savem = $this->SetFetchMode(FALSE);

		}

		$table = strtoupper($table);

		$sql = "SELECT * FROM RDB\$INDICES WHERE RDB\$RELATION_NAME = '".$table."'";

		if (!$primary) {

			$sql .= " AND RDB\$INDEX_NAME NOT LIKE 'RDB\$%'";

		} else {

			$sql .= " AND RDB\$INDEX_NAME NOT LIKE 'RDB\$FOREIGN%'";

		}

		// get index details

		$rs = $this->execute($sql);

		if (!is_object($rs)) {

			// restore fetchmode

			if (isset($savem)) {

				$this->SetFetchMode($savem);

			}

			$ADODB_FETCH_MODE = $save;

			return false;

		}

		$indexes = array();

		while ($row = $rs->FetchRow()) {

			$index = trim($row[0]);

			if (!isset($indexes[$index])) {

				if (is_null($row[3])) {

					$row[3] = 0;

				}

				$indexes[$index] = array(

					'unique' => ($row[3] == 1),

					'columns' => array()

				);

			}

			$sql = sprintf("SELECT * FROM RDB\$INDEX_SEGMENTS WHERE RDB\$INDEX_NAME = '%s' ORDER BY RDB\$FIELD_POSITION ASC",$index);

			$rs1 = $this->execute($sql);

			while ($row1 = $rs1->FetchRow()) {

				$indexes[$index]['columns'][$row1[2]] = trim($row1[1]);

			}

		}

		// restore fetchmode

		if (isset($savem)) {

			$this->SetFetchMode($savem);

		}

		$ADODB_FETCH_MODE = $save;

		return $indexes;

	}

	/**

	 * Lock a table row for a duration of a transaction.

	 *

	 * @link https://adodb.org/dokuwiki/doku.php?id=v5:reference:connection:rowlock

	 * @link https://firebirdsql.org/refdocs/langrefupd21-notes-withlock.html

	 *

	 * @param string $table The table(s) to lock rows for.

	 * @param string $where (Optional) The WHERE clause to use to determine which rows to lock.

	 * @param string $col (Optional) The columns to select.

	 *

	 * @return bool True if the locking SQL statement executed successfully, otherwise false.

	 */

	public function rowLock($table,$where,$col=false)

	{

		if ($this->transCnt==0)

			$this->beginTrans();

		if ($where) $where = ' where '.$where;

		$rs = $this->execute("SELECT $col FROM $table $where FOR UPDATE WITH LOCK");

		return !empty($rs);

	}

	/**

	 * Creates a sequence in the database.

	 *

	 * @link https://adodb.org/dokuwiki/doku.php?id=v5:reference:connection:createsequence

	 *

	 * @param string $seqname The sequence name.

	 * @param int $startID The start id.

	 *

	 * @return ADORecordSet|bool A record set if executed successfully, otherwise false.

	 */

	public function createSequence($seqname='adodbseq', $startID = 1)

	{

		$sql = sprintf($this->_genSeqSQL,$seqname,$startID);

		return $this->execute($sql);

	}

	/**

	 * A portable method of creating sequence numbers.

	 *

	 * @link https://adodb.org/dokuwiki/doku.php?id=v5:reference:connection:genid

	 *

	 * @param string $seqname (Optional) The name of the sequence to use.

	 * @param int $startID (Optional) The point to start at in the sequence.

	 *

	 * @return int

	 */

	public function genID($seqname='adodbseq',$startID=1)

	{

		$getnext = ("SELECT Gen_ID($seqname,1) FROM RDB\$DATABASE");

		$rs = @$this->Execute($getnext);

		if (!$rs) {

			$this->Execute("CREATE SEQUENCE $seqname START WITH $startID");

			$rs = $this->Execute($getnext);

		}

		if ($rs && !$rs->EOF) {

			$this->genID = (integer) reset($rs->fields);

		}

		else {

			$this->genID = 0; // false

		}

		if ($rs) {

			$rs->Close();

		}

		return $this->genID;

	}

	function selectDB($dbName)

	{

		return false;

	}

	function _handleError()

	{

		$this->_errorCode = fbird_errcode();

		$this->_errorMsg  = fbird_errmsg();

	}

	public function errorNo()

	{

		return (integer) $this->_errorCode;

	}

	function errorMsg()

	{

			return $this->_errorMsg;

	}

	/**

	 * Prepares an SQL statement and returns a handle to use.

	 * This is not used by bound parameters anymore

	 *

	 * @link https://adodb.org/dokuwiki/doku.php?id=v5:reference:connection:prepare

	 * @todo update this function to handle prepared statements correctly

	 *

	 * @param string $sql The SQL to prepare.

	 *

	 * @return bool|array The SQL that was provided and the prepared parameters,

	 *                    or false if the preparation fails

	 */

	public function prepare($sql)

	{

		$stmt = fbird_prepare($this->_connectionID,$sql);

		if (!$stmt)

			return false;

		return array($sql,$stmt);

	}

	/**

	 * Execute a query.

	 *

	 * @param string|array $sql        Query to execute.

	 * @param array        $inputarr   An optional array of parameters.

	 *

	 * @return object|bool Query identifier or true if execution successful, false if failed.

	 */

	function _query($sql, $inputarr = false)

	{

		if (!$this->isConnected()) {

			return false;

		}

		if (!$this->autoCommit && $this->_transactionID) {

			$conn = $this->_transactionID;

			$docommit = false;

		} else {

			$conn = $this->_connectionID;

			$docommit = true;

		}

		if (is_array($sql)) {

			// Prepared statement

			$fn = 'fbird_execute';

			$args = [$sql[1]];

		} else {

			$fn = 'fbird_query';

			$args = [$conn, $sql];

		}

		if (is_array($inputarr)) {

			$args = array_merge($args, $inputarr);

		}

		$ret = call_user_func_array($fn, $args);

		// fbird_query() and fbird_execute() return number of affected rows

		// ADOConnection::_Execute() expects true for INSERT/UPDATE/DELETE

		if (is_numeric($ret)) {

			$ret = true;

		}

		if ($docommit && $ret === true) {

			fbird_commit($this->_connectionID);

		}

		$this->_handleError();

		return $ret;

	}

	// returns true or false

	function _close()

	{

		if (!$this->autoCommit) {

			@fbird_rollback($this->_connectionID);

		}

		return @fbird_close($this->_connectionID);

	}

	//OPN STUFF start

	function _ConvertFieldType(&$fld, $ftype, $flen, $fscale, $fsubtype, $fprecision, $dialect3)

	{

		$fscale = abs($fscale);

		$fld->max_length = $flen;

		$fld->scale = null;

		switch($ftype){

		case 7:

		case 8:

			if ($dialect3) {

				switch($fsubtype){

					case 0:

						$fld->type = ($ftype == 7 ? 'smallint' : 'integer');

						break;

					case 1:

						$fld->type = 'numeric';

						$fld->max_length = $fprecision;

						$fld->scale = $fscale;

						break;

					case 2:

						$fld->type = 'decimal';

						$fld->max_length = $fprecision;

						$fld->scale = $fscale;

						break;

				} // switch

			} else {

				if ($fscale !=0) {

					$fld->type = 'decimal';

					$fld->scale = $fscale;

					$fld->max_length = ($ftype == 7 ? 4 : 9);

				} else {

					$fld->type = ($ftype == 7 ? 'smallint' : 'integer');

				}

			}

			break;

		case 16:

			if ($dialect3) {

				switch($fsubtype){

				case 0:

					$fld->type = 'decimal';

					$fld->max_length = 18;

					$fld->scale = 0;

					break;

				case 1:

					$fld->type = 'numeric';

					$fld->max_length = $fprecision;

					$fld->scale = $fscale;

					break;

				case 2:

					$fld->type = 'decimal';

					$fld->max_length = $fprecision;

					$fld->scale = $fscale;

					break;

				} // switch

			}

			break;

		case 10:

			$fld->type = 'float';

			break;

		case 14:

			$fld->type = 'char';

			break;

		case 27:

			if ($fscale !=0) {

				$fld->type = 'decimal';

				$fld->max_length = 15;

				$fld->scale = 5;

			} else {

				$fld->type = 'double';

			}

			break;

		case 35:

			if ($dialect3) {

				$fld->type = 'timestamp';

			} else {

				$fld->type = 'date';

			}

			break;

		case 12:

			$fld->type = 'date';

			break;

		case 13:

			$fld->type = 'time';

			break;

		case 37:

			$fld->type = 'varchar';

			break;

		case 40:

			$fld->type = 'cstring';

			break;

		case 261:

			$fld->type = 'blob';

			$fld->max_length = -1;

			break;

		} // switch

	}

	//OPN STUFF end

	/**

	 * Return an array of information about a table's columns.

	 *

	 * @param string $table The name of the table to get the column info for.

	 * @param bool $normalize (Optional) Unused.

	 *

	 * @return ADOFieldObject[]|bool An array of info for each column,

	 * or false if it could not determine the info.

	 */

	public function metaColumns($table, $normalize = true)

	{

		global $ADODB_FETCH_MODE;

		$save = $ADODB_FETCH_MODE;

		$ADODB_FETCH_MODE = ADODB_FETCH_NUM;

		$rs = $this->execute(sprintf($this->metaColumnsSQL,strtoupper($table)));

		$ADODB_FETCH_MODE = $save;

		if ($rs === false) {

			return false;

		}

		$retarr = array();

		//OPN STUFF start

		$dialect3 = $this->dialect == 3;

		//OPN STUFF end

		while (!$rs->EOF) { //print_r($rs->fields);

			$fld = new ADOFieldObject();

			$fld->name = trim($rs->fields[0]);

			//OPN STUFF start

				//print_r($rs->fields);

			$this->_ConvertFieldType(

				$fld, $rs->fields[7], $rs->fields[3], $rs->fields[4], $rs->fields[5], $rs->fields[6], $dialect3);

			if (isset($rs->fields[1]) && $rs->fields[1]) {

				$fld->not_null = true;

			}

			if (isset($rs->fields[2])) {

				$fld->has_default = true;

				$d = substr($rs->fields[2],strlen('default '));

				switch ($fld->type) {

					case 'smallint':

					case 'integer':

						$fld->default_value = (int)$d;

						break;

					case 'char':

					case 'blob':

					case 'text':

					case 'varchar':

						$fld->default_value = (string)substr($d, 1, strlen($d) - 2);

						break;

					case 'double':

					case 'float':

						$fld->default_value = (float)$d;

						break;

					default:

						$fld->default_value = $d;

						break;

				}

		//	case 35:$tt = 'TIMESTAMP'; break;

			}

			if ((isset($rs->fields[5])) && ($fld->type == 'blob')) {

				$fld->sub_type = $rs->fields[5];

			} else {

				$fld->sub_type = null;

			}

			//OPN STUFF end

			if ($ADODB_FETCH_MODE == ADODB_FETCH_NUM) $retarr[] = $fld;

			else $retarr[strtoupper($fld->name)] = $fld;

			$rs->MoveNext();

		}

		$rs->Close();

		if ( empty($retarr))

			return false;

		else return $retarr;

	}

	/**

	 * Retrieves a list of tables based on given criteria

	 *

	 * @param string|bool $ttype (Optional) Table type = 'TABLE', 'VIEW' or false=both (default)

	 * @param string|bool $showSchema (Optional) schema name, false = current schema (default)

	 * @param string|bool $mask (Optional) filters the table by name

	 *

	 * @return array list of tables

	 */

	public function metaTables($ttype = false, $showSchema = false, $mask = false)

	{

		$save = $this->metaTablesSQL;

		if (!$showSchema) {

			$this->metaTablesSQL .= " WHERE (rdb\$relation_name NOT LIKE 'RDB\$%' AND rdb\$relation_name NOT LIKE 'MON\$%' AND rdb\$relation_name NOT LIKE 'SEC\$%')";

		} elseif (is_string($showSchema)) {

			$this->metaTablesSQL .= $this->qstr($showSchema);

		}

		if ($mask) {

			$mask = $this->qstr($mask);

			$this->metaTablesSQL .= " AND table_name LIKE $mask";

		}

		$ret = ADOConnection::metaTables($ttype,$showSchema);

		$this->metaTablesSQL = $save;

		return $ret;

	}

	/**

	 * Encodes a blob, then assigns an id ready to be used

	 *

	 * @param string $blob The blob to be encoded

	 *

	 * @return bool success

	 */

	public function blobEncode( $blob )

	{

		$blobid = fbird_blob_create( $this->_connectionID);

		fbird_blob_add( $blobid, $blob );

		return fbird_blob_close( $blobid );

	}

	/**

	 * Manually decode a blob

	 *

	 * since we auto-decode all blob's since 2.42,

	 * BlobDecode should not do any transforms

	 *

	 * @param string $blob

	 *

	 * @return string the same blob

	 */

	public function blobDecode($blob)

	{

		return $blob;

	}

	/**

	 * Auto function called on read of blob to decode

	 *

	 * @param string $blob Value to decode

	 *

	 * @return string Decoded blob

	 */

	public function _blobDecode($blob)

	{

		if ($blob === null) {

			return '';

		}

		$blob_data = fbird_blob_info($this->_connectionID, $blob);

		$blobId = fbird_blob_open($this->_connectionID, $blob);

		if ($blob_data[0] > $this->maxblobsize) {

			$realBlob = fbird_blob_get($blobId, $this->maxblobsize);

			while ($string = fbird_blob_get($blobId, 8192)) {

				$realBlob .= $string;

			}

		} else {

			$realBlob = fbird_blob_get($blobId, $blob_data[0]);

		}

		fbird_blob_close($blobId);

		return $realBlob;

	}

	/**

	 * Insert blob data into a database column directly

	 * from file

	 *

	 * @param string $table table to insert

	 * @param string $column column to insert

	 * @param string $path  physical file name

	 * @param string $where string to find unique record

	 * @param string $blobtype BLOB or CLOB

	 *

	 * @return bool success

	 */

	public function updateBlobFile($table,$column,$path,$where,$blobtype='BLOB')

	{

		$fd = fopen($path,'rb');

		if ($fd === false)

			return false;

		$blob_id = fbird_blob_create($this->_connectionID);

		/* fill with data */

		while ($val = fread($fd,32768)){

			fbird_blob_add($blob_id, $val);

		}

		/* close and get $blob_id_str for inserting into table */

		$blob_id_str = fbird_blob_close($blob_id);

		fclose($fd);

		return $this->Execute("UPDATE $table SET $column=(?) WHERE $where",array($blob_id_str)) != false;

	}

	/**

	 * Insert blob data into a database column

	 *

	 * @param string $table table to insert

	 * @param string $column column to insert

	 * @param string $val    value to insert

	 * @param string $where string to find unique record

	 * @param string $blobtype BLOB or CLOB

	 *

	 * @return bool success

	 */

	public function updateBlob($table,$column,$val,$where,$blobtype='BLOB')

	{

		$blob_id = fbird_blob_create($this->_connectionID);

		// fbird_blob_add($blob_id, $val);

		// replacement that solves the problem by which only the first modulus 64K /

		// of $val are stored at the blob field ////////////////////////////////////

		// Thx Abel Berenstein  aberenstein#afip.gov.ar

		$len = strlen($val);

		$chunk_size = 32768;

		$tail_size = $len % $chunk_size;

		$n_chunks = ($len - $tail_size) / $chunk_size;

		for ($n = 0; $n < $n_chunks; $n++) {

			$start = $n * $chunk_size;

			$data = substr($val, $start, $chunk_size);

			fbird_blob_add($blob_id, $data);

		}

		if ($tail_size) {

			$start = $n_chunks * $chunk_size;

			$data = substr($val, $start, $tail_size);

			fbird_blob_add($blob_id, $data);

		}

		// end replacement /////////////////////////////////////////////////////////

		$blob_id_str = fbird_blob_close($blob_id);

		return $this->execute("UPDATE $table SET $column=(?) WHERE $where",array($blob_id_str)) != false;

	}

	/**

	 * Returns a portably-formatted date string from a timestamp database column.

	 *

	 * @link https://adodb.org/dokuwiki/doku.php?id=v5:reference:connection:sqldate

	 *

	 * Firebird does not support an AM/PM format, so the A indicator always shows AM

	 *

	 * @param string $fmt The date format to use.

	 * @param string|bool $col (Optional) The table column to date format, or if false, use NOW().

	 *

	 * @return string The SQL DATE_FORMAT() string, or empty if the provided date format was empty.

	 */

	public function sqlDate($fmt, $col=false)

	{

		if (!$col)

			$col = 'CURRENT_TIMESTAMP';

		$s = '';

		$len = strlen($fmt);

		for ($i=0; $i < $len; $i++) {

			if ($s) $s .= '||';

			$ch = $fmt[$i];

			$choice = strtoupper($ch);

			switch($choice) {

			case 'Y':

				$s .= "EXTRACT(YEAR FROM $col)";

				break;

			case 'M':

				$s .= "RIGHT('0' || TRIM(EXTRACT(MONTH FROM $col)),2)";

				break;

			case 'W':

				// The more accurate way of doing this is with a stored procedure

				// See http://wiki.firebirdsql.org/wiki/index.php?page=DATE+Handling+Functions for details

				$s .= "((EXTRACT(YEARDAY FROM $col) - EXTRACT(WEEKDAY FROM $col - 1) + 7) / 7)";

				break;

			case 'Q':

				$s .= "CAST(((EXTRACT(MONTH FROM $col)+2) / 3) AS INTEGER)";

				break;

			case 'D':

				$s .= "RIGHT('0' || TRIM(EXTRACT(DAY FROM $col)),2)";

				break;

			case 'H':

				$s .= "RIGHT('0' || TRIM(EXTRACT(HOUR FROM $col)),2)";

				break;

			case 'I':

				$s .= "RIGHT('0' || TRIM(EXTRACT(MINUTE FROM $col)),2)";

				break;

			case 'S':

				//$s .= "CAST((EXTRACT(SECOND FROM $col)) AS INTEGER)";

				$s .= "RIGHT('0' || TRIM(EXTRACT(SECOND FROM $col)),2)";

				break;

			case 'A':

				$s .= $this->qstr('AM');

				break;

			default:

				if ($ch == '\\') {

					$i++;

					$ch = substr($fmt,$i,1);

				}

				$s .= $this->qstr($ch);

				break;

			}

		}

		return $s;

	}

	/**

	 * Creates a portable date offset field, for use in SQL statements.

	 *

	 * @link https://adodb.org/dokuwiki/doku.php?id=v5:reference:connection:offsetdate

	 *

	 * @param float $dayFraction A day in floating point

	 * @param string|bool $date (Optional) The date to offset. If false, uses CURDATE()

	 *

	 * @return string

	 */

	public function offsetDate($dayFraction, $date=false)

	{

		if (!$date)

			$date = $this->sysTimeStamp;

		$fraction = $dayFraction * 24 * 3600;

		return sprintf("DATEADD (second, %s, %s)  FROM RDB\$DATABASE",$fraction,$date);

	}

	// Note that Interbase 6.5 uses this ROWS instead - don't you love forking wars!

	// 		SELECT col1, col2 FROM table ROWS 5 -- get 5 rows

	//		SELECT col1, col2 FROM TABLE ORDER BY col1 ROWS 3 TO 7 -- first 5 skip 2

	/**

	 * Executes a provided SQL statement and returns a handle to the result, with the ability to supply a starting

	 * offset and record count.

	 *

	 * @link https://adodb.org/dokuwiki/doku.php?id=v5:reference:connection:selectlimit

	 *

	 * @param string $sql The SQL to execute.

	 * @param int $nrows (Optional) The limit for the number of records you want returned. By default, all results.

	 * @param int $offset (Optional) The offset to use when selecting the results. By default, no offset.

	 * @param array|bool $inputarr (Optional) Any parameter values required by the SQL statement, or false if none.

	 * @param int $secs2cache (Optional) If greater than 0, perform a cached execute. By default, normal execution.

	 *

	 * @return ADORecordSet|false The query results, or false if the query failed to execute.

	 */

	public function selectLimit($sql,$nrows=-1,$offset=-1,$inputarr=false, $secs2cache=0)

	{

		$nrows = (integer) $nrows;

		$offset = (integer) $offset;

		$str = 'SELECT ';

		if ($nrows >= 0) $str .= "FIRST $nrows ";

		$str .=($offset>=0) ? "SKIP $offset " : '';

		$sql = preg_replace('/^[ \t]*select/i',$str,$sql);

		if ($secs2cache)

			$rs = $this->cacheExecute($secs2cache,$sql,$inputarr);