DB.php

<?php
//
// +----------------------------------------------------------------------+
// | PHP version 4.0                                                      |
// +----------------------------------------------------------------------+
// | Copyright (c) 1997, 1998, 1999, 2000 The PHP Group                   |
// +----------------------------------------------------------------------+
// | This source file is subject to version 2.02 of the PHP license,      |
// | that is bundled with this package in the file LICENSE, and is        |
// | available at through the world-wide-web at                           |
// | http://www.php.net/license/2_02.txt.                                 |
// | If you did not receive a copy of the PHP license and are unable to   |
// | obtain it through the world-wide-web, please send a note to          |
// | license@php.net so we can mail you a copy immediately.               |
// +----------------------------------------------------------------------+
// | Authors: Stig Bakken <ssb@fast.no>                                   |
// |                                                                      |
// +----------------------------------------------------------------------+
//
// $Id$
//
// Database independent query interface.
//

require_once "PEAR.php";

/*
 * The method mapErrorCode in each DB_dbtype implementation maps
 * native error codes to one of these.
 *
 * If you add an error code here, make sure you also add a textual
 * version of it in DB::errorMessage().
 */
define("DB_OK",                      	0);
define("DB_ERROR",                     -1);
define("DB_ERROR_SYNTAX",              -2);
define("DB_ERROR_CONSTRAINT",          -3);
define("DB_ERROR_NOT_FOUND",           -4);
define("DB_ERROR_ALREADY_EXISTS",      -5);
define("DB_ERROR_UNSUPPORTED",         -6);
define("DB_ERROR_MISMATCH",            -7);
define("DB_ERROR_INVALID",             -8);
define("DB_ERROR_NOT_CAPABLE",         -9);
define("DB_ERROR_TRUNCATED",          -10);
define("DB_ERROR_INVALID_NUMBER",     -11);
define("DB_ERROR_INVALID_DATE",       -12);
define("DB_ERROR_DIVZERO",            -13);
define("DB_ERROR_NODBSELECTED",       -14);
define("DB_ERROR_CANNOT_CREATE",      -15);
define("DB_ERROR_CANNOT_DELETE",      -16);
define("DB_ERROR_CANNOT_DROP",        -17);
define("DB_ERROR_NOSUCHTABLE",        -18);
define("DB_ERROR_NOSUCHFIELD",        -19);
define("DB_ERROR_NEED_MORE_DATA",     -20);
define("DB_ERROR_NOT_LOCKED",         -21);
define("DB_ERROR_VALUE_COUNT_ON_ROW", -22);


/*
 * Warnings are not detected as errors by DB::isError(), and are not
 * fatal.  You can detect whether an error is in fact a warning with
 * DB::isWarning().
 */
define("DB_WARNING",             -1000);
define("DB_WARNING_READ_ONLY",   -1001);


/*
 * These constants are used when storing information about prepared
 * statements (using the "prepare" method in DB_dbtype).
 *
 * The prepare/execute model in DB is mostly borrowed from the ODBC
 * extension, in a query the "?" character means a scalar parameter.
 * There is one extension though, a "*" character means an opaque
 * parameter.  An opaque parameter is simply a file name, the real
 * data are in that file (useful for stuff like putting uploaded files
 * into your database).
 */
define("DB_PARAM_SCALAR",           1);
define("DB_PARAM_OPAQUE",           2);


/*
 * These constants define different ways of returning binary data
 * from queries.  Again, this model has been borrowed from the ODBC
 * extension.
 *
 * DB_BINMODE_PASSTHRU sends the data directly through to the browser
 * when data is fetched from the database.
 * DB_BINMODE_RETURN lets you return data as usual.
 * DB_BINMODE_CONVERT returns data as well, only it is converted to
 * hex format, for example the string "123" would become "313233".
 */
define("DB_BINMODE_PASSTHRU",       1);
define("DB_BINMODE_RETURN",         2);
define("DB_BINMODE_CONVERT",        3);



/**
 * This is a special constant that tells DB the user hasn't specified
 * any particular get mode, so the default should be used.
 */
define('DB_FETCHMODE_DEFAULT', 0);
/**
 * Column data indexed by numbers, ordered from 0 and up
 */
define('DB_FETCHMODE_ORDERED', 1);
/**
 * Column data indexed by column names
 */
define('DB_FETCHMODE_ASSOC',   2);
/**
 * For multi-dimensional results: normally the first level of arrays
 * is the row number, and the second level indexed by column number or name.
 * DB_FETCHMODE_FLIPPED switches this order, so the first level of arrays
 * is the column name, and the second level the row number.
 */
define('DB_FETCHMODE_FLIPPED', 4);

/* for compatibility */
define('DB_GETMODE_ORDERED', DB_FETCHMODE_ORDERED);
define('DB_GETMODE_ASSOC',   DB_FETCHMODE_ASSOC);
define('DB_GETMODE_FLIPPED', DB_FETCHMODE_FLIPPED);

/**
 * The main "DB" class is simply a container class with some static
 * methods for creating DB objects as well as some utility functions
 * common to all parts of DB.
 *
 * The object model of DB is as follows (indentation means inheritance):
 *
 * DB           The main DB class.  This is simply a utility class
 *              with some "static" methods for creating DB objects as
 *              well as common utility functions for other DB classes.
 * 
 * DB_common    The base for each DB implementation.  Provides default
 * |            implementations (in OO lingo virtual methods) for
 * |            the actual DB implementations as well as a bunch of
 * |            query utility functions.
 * |
 * +-DB_mysql   The DB implementation for MySQL.  Inherits DB_common.
 *              When calling DB::factory or DB::connect for MySQL
 *              connections, the object returned is an instance of this
 *              class.
 *
 * @version  2
 * @author   Stig Bakken <ssb@fast.no>
 * @since    PHP 4.0
 */
class DB {
	/**
	 * Create a new DB object for the specified database type
	 *
	 * @param $type string database type, for example "mysql"
	 *
	 * @return object a newly created DB object, or a DB error code on
	 * error
	 */
	function &factory($type) {
		@include_once("DB/${type}.php");
		$classname = 'DB_' . $type;
		$obj = @new $classname;
		if (!$obj) {
			return new DB_Error(DB_ERROR_NOT_FOUND);
		}
		return $obj;
	}

	/**
	 * Create a new DB object and connect to the specified database
	 *
	 * @param $dsn string "data source name", see the DB::parseDSN
	 * method for a description of the dsn format.
	 *
	 * @param $persistent bool whether this connection should be
	 * persistent.  Ignored if the backend extension does not support
	 * persistent connections.
	 *
	 * @return object a newly created DB object, or a DB error code on
	 * error
	 */
	function &connect($dsn, $persistent = false) {
		$dsninfo = DB::parseDSN($dsn);
		$type = $dsninfo['phptype'];
		@include_once("DB/${type}.php");
		$classname = 'DB_' . $type;
		$obj = @new $classname;
		if (!$obj) {
			return new DB_Error(DB_ERROR_NOT_FOUND);
		}
		$err = $obj->connect($dsninfo, $persistent);
		if (DB::isError($err)) {
			return $err;
		}
		return $obj;
	}

	/**
	 * Return the DB API version
	 *
	 * @return int the DB API version number
	 */
    function apiVersion() {
		return 2;
    }

	/**
	 * Tell whether a result code from a DB method is an error
	 *
	 * @param $value int result code
	 *
	 * @return bool whether $value is an error
	 */
	function isError($value) {
		return is_object($value) &&
			(get_class($value) == "db_error" ||
			 is_subclass_of($value, "db_error"));
	}

	/**
	 * Tell whether a result code from a DB method is a warning.
	 * Warnings differ from errors in that they are generated by DB,
	 * and are not fatal.
	 *
	 * @param $value mixed result value
	 *
	 * @return bool whether $value is a warning
	 */
	function isWarning($value) {
		return is_object($value) &&
			(get_class($value) == "db_warning" ||
			 is_subclass_of($value, "db_warning"));
	}

	/**
	 * Return a textual error message for a DB error code
	 *
	 * @param $value int error code
	 *
	 * @return string error message, or false if the error code was
	 * not recognized
	 */
	function errorMessage($value) {
		if (!isset($errorMessages)) {
			$errorMessages = array(
				DB_ERROR                    => "unknown error",
				DB_ERROR_ALREADY_EXISTS     => "already exists",
				DB_ERROR_CANNOT_CREATE      => "can not create",
				DB_ERROR_CANNOT_DELETE      => "can not delete",
				DB_ERROR_CANNOT_DROP        => "can not drop",
				DB_ERROR_CONSTRAINT         => "constraint violation",
				DB_ERROR_DIVZERO            => "division by zero",
				DB_ERROR_INVALID            => "invalid",
				DB_ERROR_INVALID_DATE       => "invalid date or time",
				DB_ERROR_INVALID_NUMBER     => "invalid number",
				DB_ERROR_MISMATCH           => "mismatch",
				DB_ERROR_NODBSELECTED       => "no database selected",
				DB_ERROR_NOSUCHFIELD        => "no such field",
				DB_ERROR_NOSUCHTABLE        => "no such table",
				DB_ERROR_NOT_CAPABLE        => "DB backend not capable",
				DB_ERROR_NOT_FOUND          => "not found",
				DB_ERROR_NOT_LOCKED         => "not locked",
				DB_ERROR_SYNTAX             => "syntax error",
				DB_ERROR_UNSUPPORTED        => "not supported",
				DB_ERROR_VALUE_COUNT_ON_ROW => "value count on row",
				DB_OK                       => "no error",
				DB_WARNING                  => "unknown warning",
				DB_WARNING_READ_ONLY        => "read only"
			);
		}
		if (DB::isError($value)) {
			$value = $value->code;
		}
		return $errorMessages[$value];
	}

	/**
	 * Parse a data source name
	 *
	 * @param $dsn string Data Source Name to be parsed
	 *
	 * @return array an associative array with the following keys:
	 * <dl>
	 *  <dt>phptype</dt>
	 *  <dd>Database backend used in PHP (mysql, odbc etc.)</dd>
	 *  <dt>dbsyntax</dt>
	 *  <dd>Database used with regards to SQL syntax etc.</dd>
	 *  <dt>protocol</dt>
	 *  <dd>Communication protocol to use (tcp, unix etc.)</dd>
	 *  <dt>hostspec</dt>
	 *  <dd>Host specification (hostname[:port])</dd>
	 *  <dt>database</dt>
	 *  <dd>Database to use on the DBMS server</dd>
	 *  <dt>username</dt>
	 *  <dd>User name for login</dd>
	 *  <dt>password</dt>
	 *  <dd>Password for login</dd>
	 * </dl>
	 * </p>
	 *
	 * <p>
	 * The format of the supplied DSN is in its fullest form:
	 * <ul>
	 *  <li>phptype(dbsyntax)://username:password@protocol+hostspec/database</li>
	 * </ul>
	 * Most variations are allowed:
	 * <ul>
	 *  <li>phptype://username:password@protocol+hostspec/database</li>
	 *  <li>phptype://username:password@hostspec/database</li>
	 *  <li>phptype://username:password@hostspec</li>
	 *  <li>phptype://hostspec/database</li>
	 *  <li>phptype://hostspec</li>
	 *  <li>phptype(dbsyntax)</li>
	 *  <li>phptype</li>
	 * </ul>
	 * </p>
	 *
	 * @return bool FALSE is returned on error
	 */
	function parseDSN($dsn) {
		if (is_array($dsn))
			return $dsn;
		
		$parsed = array(
			'phptype'  => false,
			'dbsyntax' => false,
			'protocol' => false,
			'hostspec' => false,
			'database' => false,
			'username' => false,
			'password' => false
		);
		if (preg_match('|^([^:]+)://|', $dsn, $arr)) {
			$dbtype = $arr[1];
			$dsn = preg_replace('|^[^:]+://|', '', $dsn);
			// match "phptype(dbsyntax)"
			if (preg_match('|^([^\(]+)\((.+)\)$|', $dbtype, $arr)) {
				$parsed['phptype'] = $arr[1];
				$parsed['dbsyntax'] = $arr[2];
			} else {
				$parsed['phptype'] = $dbtype;
			}
		} else {
			// match "phptype(dbsyntax)"
			if (preg_match('|^([^\(]+)\((.+)\)$|', $dsn, $arr)) {
				$parsed['phptype'] = $arr[1];
				$parsed['dbsyntax'] = $arr[2];
			} else {
				$parsed['phptype'] = $dsn;
			}
			return $parsed;
		}

		if (preg_match('|^(.*)/([^/]+)/?$|', $dsn, $arr)) {
			$parsed['database'] = $arr[2];
			$dsn = $arr[1];
		}

		if (preg_match('|^([^:]+):([^@]+)@?(.*)$|', $dsn, $arr)) {
			$parsed['username'] = $arr[1];
			$parsed['password'] = $arr[2];
			$dsn = $arr[3];
		} elseif (preg_match('|^([^:]+)@(.*)$|', $dsn, $arr)) {
			$parsed['username'] = $arr[1];
			$dsn = $arr[2];
		}
		
		if (preg_match('|^([^\+]+)\+(.*)$|', $dsn, $arr)) {
			$parsed['protocol'] = $arr[1];
			$dsn = $arr[2];
		}

		if (!$parsed['database'])
			$dsn = preg_replace('|/+$|', '', $dsn);

		$parsed['hostspec'] = urldecode($dsn);

		if (!$parsed['dbsyntax']) {
			$parsed['dbsyntax'] = $parsed['phptype'];
		}

		return $parsed;
	}
}

/**
 * This class implements a wrapper for a DB result set.
 * A new instance of this class will be returned by the DB implementation
 * after processing a query that returns data.
 *
 * @author Stig Bakken <ssb@fast.no>
 */
class DB_result {

    var $dbh;
    var $result;

    /**
	 * DB_result constructor.
	 * @param   $dbh    DB object reference
	 * @param   $result result resource id
	 */
    function DB_result(&$dbh, $result) {
		$this->dbh = &$dbh;
		$this->result = $result;
    }

	/**
	 * Fetch and return a row of data.
	 * @return  array   a row of data, or false on error
	 */
    function fetchRow($fetchmode = DB_FETCHMODE_DEFAULT) {
		if ($fetchmode == DB_FETCHMODE_DEFAULT) {
			$fetchmode = $this->dbh->fetchmode;
		}
		return $this->dbh->fetchRow($this->result, $fetchmode);
    }

    /**
	 * Fetch a row of data into an existing array.
	 *
	 * @param   $arr    reference to data array
	 * @return  int     error code
	 */
    function fetchInto(&$arr, $fetchmode = DB_FETCHMODE_DEFAULT) {
		if ($fetchmode == DB_FETCHMODE_DEFAULT) {
			$fetchmode = $this->dbh->fetchmode;
		}
		return $this->dbh->fetchInto($this->result, $arr, $fetchmode);
    }

	/**
	 * Get the the number of columns in a result set.
	 *
	 * @return int the number of columns, or a DB error code
	 */
	function numCols() {
		return $this->dbh->numCols($this->result);
	}

    /**
	 * Frees the resources allocated for this result set.
	 * @return  int     error code
	 */
    function free() {
		$err = $this->dbh->freeResult($this->result);
		if (DB::isError($err)) {
			return $err;
		}
		$this->result = false;
		return true;
    }
}

/**
 * DB_Error implements a class for reporting portable database error
 * messages.
 *
 * @author Stig Bakken <ssb@fast.no>
 */
class DB_Error extends PEAR_Error {
	/**
	 * DB_Error constructor.
	 *
	 * @param $code mixed DB error code, or string with error message.
	 * @param $mode int what "error mode" to operate in
	 * @param $level what error level to use for $mode & PEAR_ERROR_TRIGGER
	 * @param $debuginfo additional debug info, such as the last query
	 *
	 * @access public
	 *
	 * @see PEAR_Error
	 */
	function DB_Error($code = DB_ERROR,
					  $mode = PEAR_ERROR_RETURN,
					  $level = E_USER_NOTICE,
					  $debuginfo = null) {
		if (is_int($code)) {
			$this->PEAR_Error("DB Error: " . DB::errorMessage($code), $code, $mode, $level, $debuginfo);
		} else {
			$this->PEAR_Error("DB Error: $code", 0, $mode, $level, $debuginfo);
		}
	}
}

/**
 * DB_Warning implements a class for reporting portable database
 * warning messages.
 *
 * @author Stig Bakken <ssb@fast.no>
 */
class DB_Warning extends PEAR_Error {
	/**
	 * DB_Warning constructor.
	 *
	 * @param $code mixed DB error code, or string with error message.
	 * @param $mode int what "error mode" to operate in
	 * @param $level what error level to use for $mode == PEAR_ERROR_TRIGGER
	 * @param $debuginfo additional debug info, such as the last query
	 *
	 * @access public
	 *
	 * @see PEAR_Error
	 */
	function DB_Warning($code = DB_WARNING,
						$mode = PEAR_ERROR_RETURN,
						$level = E_USER_NOTICE,
						$debuginfo = null) {
		if (is_int($code)) {
			$this->PEAR_Error("DB Warning: " . DB::errorMessage($code), $code, $mode, $level, $debuginfo);
		} else {
			$this->PEAR_Error("DB Warning: $code", 0, $mode, $level, $debuginfo);
		}
	}
}

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?>