Abstraction Layers
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<?php
/*
------------------------------------------------------------------------------------------
dbdriver class
version 1.0Beta
------------------------------------------------------------------------------------------
the dbdriver class is a Database abstract class developed for MySQL. Object is designed
to work with the other PHP supported DB systems. You need to adjust the functions.
The reason for such many details in the methods is because not all functions are
supported accross the bord and the SQL language can vary from a platform to another.
Therefore, by being quite specific about each action, we help the developper of the main
application to concentrate on building a generic code...
License Information
-------------------
Copyright (C) 2003 Fabien Papleux, fpa Technology Consulting
This program is free software; you can redistribute it and/or modify it under the terms
of the GNU General Public License as published by the Free Software Foundation,
version 2 of the License.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program;
if not, you can get a copy at http://www.gnu.org/licenses/gpl.txt
Contact Information
-------------------
Should you have any questions / remarks / suggestions, please don't hesitate to
contact me at dev_support@fpatech.com
Synopsis
--------
Constants: Constants are defined outside the scope of the class and are global.
DBDRIVER = 1 : Indicates that the DBDRIVER Module is loaded
CNT_AUTOINCREMENT = 1 : Constraint -> Auto Increment
CNT_PRIMARYKEY = 2 : Constraint -> Primary Key
CNT_UNIQUE = 4 : Constraint -> Unique
CNT_NOTNULL = 8 : Constraint -> Not Null
CNT_INDEXED = 16 : Constraint -> Indexed
Properties:
$server : server name, with port# if necessary
$link_id : ID for the current connection
$user_name : Name of the user
$user_pwd : User Password
$current_db : name of current database
$current_table : bane of the current table. Usually used in conjunction w/
structural work.
$result_id : ID for the last result-set
Methods:
Constructor and structural methods:
dbdriver($server_addr, $user, $pwd)
classprint()
connect($server_addr, $user, $pwd)
close()
db_create($database)
db_select($database)
db_exists($database)
db_drop()
table_create($table)
table_select($table)
table_exists($table)
table_drop([$table])
table_rename($table, $new_name)
field_create($field_name, $type, $size, [$constraints], [$table_name])
field_exists($field_name, [$table_name])
field_drop($field_name, [$table_name])
All other methods:
query($query)
data_seek($rownumber)
num_rows()
fetch_row()
errno()
error()
Known Bugs
----------
Future Development
------------------
1) An export function that exports a result_set to a file and returns a filename
to download.
2) An import function capable of loading a comma-separated file and/or an XML
file and either create a table with it or update an existing one.
------------------------------------------------------------------------------------------
*/
// CONSTANTS DEFINITIONS
// ------------------------------------------------------------------------------------------
define("DBDRIVER", 1);
define("CNT_AUTOINCREMENT", 1);
define("CNT_PRIMARYKEY", 2);
define("CNT_UNIQUE", 4);
define("CNT_NOTNULL", 8);
define("CNT_INDEXED", 16);
class dbdriver {
// PROPERTIES DECLARATION
// ------------------------------------------------------------------------------------------
var $server;
var $link_id;
var $user_name;
var $user_pwd;
var $current_db;
var $current_table;
var $result_id;
// CONSTRUCTOR
// The constructor will initialize the properties and attempt to connect to the serer.
// Should it fail, $link_id will be Null
// ------------------------------------------------------------------------------------------
function dbdriver ($server_addr = "localhost", $user = "", $pwd = "") {
$this->result_id = 0;
$this->current_table = "";
$this->current_db = "";
$this->link_id = 0;
$this->connect($server_addr, $user, $pwd);
}
// CLASSPRINT
// The purpose of the Print method is to send to the client all the information about
// the object for testing and debugging purposes
// ------------------------------------------------------------------------------------------
function classprint() {
echo("<b>printing information about dbdriver object</b><br><br>");
echo("object properties:<br>");
echo("Server: $this->server<br>");
echo("link_id: {$this->link_id}<br>");
echo("user_name: {$this->user_name}<br>");
echo("user_pwd: {$this->user_pwd}<br>");
echo("current_db: {$this->current_db}<br>");
echo("current_table: {$this->current_table}<br>");
echo("result_id: {$this->result_id}<br><br>");
if ($this->link_id) echo("driver is connected to server<br>");
else echo("driver is not connected to server<br>");
}
// CONNECT
// The connect method connects to a server and returns the link_id upon successful
// connection. Returns False on fail.
// ------------------------------------------------------------------------------------------
function connect ($server_addr, $user, $pwd) {
$this->server = $server_addr;
$this->user_name = $user;
$this->user_pwd = $pwd;
$this->link_id = mysql_connect($this->server, $this->user_name, $this->user_pwd);
return $this->link_id;
}
// CLOSE
// The close method closes the server connection. It always returns 1
// ------------------------------------------------------------------------------------------
function close() {
if ($this->link_id) {
$this->current_db = "";
$this->current_table = "";
$result_id = 0;
mysql_close($this->link_id);
}
return 1;
}
// DB_CREATE
// Creates a database on current server
// ------------------------------------------------------------------------------------------
function db_create ($db_name) {
$result = 0;
if ($this->link_id) {
$result = mysql_query("CREATE DATABASE {$db_name}");
if ($result) return $this->db_select($db_name);
}
return $result;
}
// DB_SELECT
// Selects a database on the current server. Returns False if DB cannot be found.
// ------------------------------------------------------------------------------------------
function db_select($database) {
if ($this->link_id) {
if (mysql_select_db($database, $this->link_id)) {
$this->current_db = $database;
$this->result_id = 0;
return 1;
}
}
return 0;
}
// DB_EXISTS
// Returns True if specified database exists on current server. False if not.
// As for the other similar functions, this is useful to check on the version of a database
// in order to build auto-upgrading applications
// ------------------------------------------------------------------------------------------
function db_exists($database) {
$original_db = $this->current_db;
$result = 0;
if ($this->link_id) {
$result = mysql_select_db($database, $this->link_id);
$this->result_id = 0;
if ($original_db != "") mysql_select_db($original_db, $this->link_id);
}
return $result;
}
// DB_DROP
// Removes the current database from the server
// ------------------------------------------------------------------------------------------
function db_drop () {
if (($this->link_id) && ($this->current_db != "")) {
$current_db = "";
$result_id = 0;
return mysql_query("DROP DATABASE {$db_name}");
}
return 0;
}
// TABLE_CREATE
// Creates an empty table in the current database and sets default table to newly created.
// Automatically creates a BIGINT PRIMARY KEY AUTO_INCREMENT field called 'ID' for ease.
// ------------------------------------------------------------------------------------------
function table_create($table) {
if ($this->link_id && ($this->current_db != "")) {
$result = mysql_query("CREATE TABLE $table (ID BIGINT AUTO_INCREMENT
PRIMARY KEY);", $this->link_id);
if ($result) {
$this->current_table = $table;
return 1;
}
}
return 0;
}
// TABLE_SELECT
// Selects a table as the current table in current DB. Return False upon failure.
// ------------------------------------------------------------------------------------------
function table_select($table) {
if (($this->link_id) && ($this->current_db != "") && ($this->table_exists($table))) {
$this->current_table = $table;
return 1;
}
return 0;
}
// TABLE_EXISTS
// Checks whether specified table exists in current database.
// ------------------------------------------------------------------------------------------
function table_exists($table) {
$found = 0;
if (($this->link_id) && ($this->current_db != "")) {
$result_id = mysql_list_tables($this->current_db);
while ($record = mysql_fetch_row($result_id)) {
if (strtoupper($table) == strtoupper($record[0])) {
$found = 1;
}
}
}
return $found;
}
// TABLE_DROP
// Drops the current table from the current database. Returns False on failure.
// ------------------------------------------------------------------------------------------
function table_drop($table = "") {
if ($this->link_id && ($this->current_db != "")) {
if ($table != "") $this->current_table = $table;
$result = mysql_query("DROP TABLE IF EXISTS $this->current_table");
if ($result) $this->current_table = "";
return $result;
} else return 0;
}
// TABLE_RENAME
// Renames a table
// ------------------------------------------------------------------------------------------
function table_rename($table, $new_name) {
if ($this->link_id && ($this->current_db != "")) {
$result = mysql_query("ALTER TABLE $table RENAME TO $new_name");
if ($result) $this->current_table = $new_name;
return $result;
} else return 0;
}
// FIELD_CREATE
// Creates a field in current table or any specified table. constraints can be any
// sum of the CNT_ constants. For instance, a UNIQUE and INDEXED field would be
// sent a $constraints of CNT_UNIQUE+CNT_INDEXED.
// For fields which size is preset, use 0 for the $size parameter if you need to send
// any constraints.
// ------------------------------------------------------------------------------------------
function field_create($field_name, $type, $size = 0, $constraints = 0, $table_name = "") {
if ($this->link_id && ($this->current_db != "") && (($this->current_table != "") ||
($table_name != ""))) {
if ($table_name == "") $table_name = $this->current_table;
$nullnotnull = "NULL ";
$autoincrement = " ";
$primarykey = " ";
$unique = " ";
$indexed = " ";
$sql = "";
if ($constraints >= 16) {
$indexed = "INDEX $field_name ";
$constraints -= 16;
}
if ($constraints >= 8) {
$nullnotnull = "NOT NULL ";
$constraints -= 8;
}
if ($constraints >= 4) {
$unique = "UNIQUE ";
$constraints -= 4;
}
if ($constraints >= 2) {
$primarykey = "PRIMARY KEY ";
$constraints -= 2;
}
if ($constraints == 1) {
$autoincrement = "AUTO_INCREMENT ";
$constraints -= 1;
}
$sql = "ALTER TABLE $table_name ADD COLUMN $field_name $type ";
if ($size) $sql = $sql . "(" . $size . ") ";
$sql = $sql . $nullnotnull . $autoincrement . $primarykey . $unique;
echo $sql . "<br>";
$result = mysql_query($sql, $this->link_id);
if ($result) {
if ($sql2 != "") mysql_query($sql2, $this->link_id);
if ($sql3 != "") mysql_query($sql3, $this->link_id);
}
return $result;
} else return 0;
}
// FIELD_EXISTS
// Checks whether specified field exists in current or specified table.
// ------------------------------------------------------------------------------------------
function field_exists($field_name, $table_name = "") {
$found = 0;
$t = 0;
if ($this->link_id && ($this->current_db != "") && (($this->current_table != "") ||
($table_name != ""))) {
if ($table_name != "") $this->current_table = $table_name;
$result_id = mysql_list_fields( $this->current_db, $this->current_table,
$this->link_id);
for ($t = 0; $t < mysql_num_fields($result_id); $t++) {
if (strtoupper($field_name) ==
strtoupper(mysql_field_name($result_id, $t))) {
$found = 1;
}
}
}
return $found;
}
// FIELD_DROP
// Drops the specified field from the current or specified table in current database
// ------------------------------------------------------------------------------------------
function field_drop($field_name, $table_name = "") {
$result = 0;
if ($this->link_id && ($this->current_db != "") && (($this->current_table != "") ||
($table_name != ""))) {
if ($table_name != "") $this->current_table = $table_name;
$result = mysql_query("ALTER TABLE $this->current_table
DROP INDEX $field_name", $this->link_id);
$result = mysql_query("ALTER TABLE $this->current_table
DROP COLUMN $field_name", $this->link_id);
}
return $result;
}
// QUERY
// Executes the specified query in current database
// ------------------------------------------------------------------------------------------
function query($sql) {
$this->return_id = 0;
if ($this->link_id) $this->result_id = mysql_query($sql, $this->link_id);
return $this->result_id;
}
// DATA_SEEK
// Seeks a certain row within the current resultset.
// ------------------------------------------------------------------------------------------
function data_seek($rownumber) {
if ($this->result_id) return mysql_data_seek($this->result_id, $rownumber);
return 0;
}
// NUM_ROWS
// Seeks a certain row within the current resultset.
// ------------------------------------------------------------------------------------------
function num_rows() {
if ($this->result_id) return mysql_num_rows($this->result_id);
return 0;
}
// FETCH_ROW
// Returns next row in current result set
// ------------------------------------------------------------------------------------------
function fetch_row() {
if ($this->result_id) return mysql_fetch_row($this->result_id);
return 0;
}
// ERROR
// Returns last MySQL error message
// ------------------------------------------------------------------------------------------
function error() { return mysql_error(); }
// ERRNO
// Returns last MySQL error number
// ------------------------------------------------------------------------------------------
function errno() { return mysql_errno(); }
}
?>
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Usage Example
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include ("dbdriver.cls.php");
set $db = new dbdriver("localhost", "manager", "xxczd");
$db->db_create("system");
$db->table_create("settings");
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