Abstraction Layers
|
|
|
|
<?php
///////////////////////
// Author: Trevin Chow
// Email: t1@mail.com
// Date: February 21, 2000
// Last Updated: August 14, 2001
//
// Description:
// Abstracts both the php function calls and the server information to POSTGRES
// databases. Utilizes class variables to maintain connection information such
// as number of rows, result id of last operation, etc.
//
// Sample Usage:
// include("include/dblib.php");
// $db = new phpDB();
// $db->connect("foobar");
// $db->exec("SELECT * from TREVIN");
// while ($db->nextRow()) {
// $rs = $db->fobject();
// echo "$rs->description : $rs->color : $rs->price <br>n";
// }
//
// Modification History:
// Modification History:
// - v1.04b, 08/11/2001, Trevin Chow, t1@mail.com
//
// Fixed following bugs:
// * added in call to moveFirst() in exec() to ensure that on subsequent calls to exec
// we are moving row pointer to beginning again. Previously, row pointer wasn't being
// updated.
//
// - v1.04a, 08/09/2001, Trevin Chow, t1@mail.com
//
// Fixed following bugs introduced in v1.03:
// * connect() function had problem with setting password. Instead of using $this->password, was using $this->userName again for some reason.
//
// - v1.04, 07/29/2001, Trevin Chow, t1@mail.com
//
// Added Following function(s):
// * currRow() - return current row
//
// - v1.03, 05/18/2001, Lee Pang, wleepang@hotmail.com
//
// Added the following functions:
// * moveNext() - same as nextRow(), better syntax for VB/ASP converts like myself.
// * movePrevious() - like nextRow(), just in the opposite direction.
// * recordCount() - same as numRows(), better syntax for VB/ASP converts
// * columnCount() - same as numFields, better syntax
// * querySafe() - removes "r" and "n" and replaces "'" with "'" in input query
// * sqlSafe() - replaces "'" with "''"
//
// Added more comprehensive error handling:
// * internal error code $errorCode
// * in connect()
// * in errorMsg()
//
// Modified following functions:
// * connect() - generates connection string based on available data
//
// Fixed the following bugs:
// * Syntax error in numAffected() - if ($this->result = null) ... to if ($this->result == null) ...
///////////////////////
class phpDB {
// set when connect() is called, defined in set_db_info()
var $hostName = '';
var $port = '';
var $userName = '';
var $password = '';
var $databaseName = '';
var $connectionID = -1;
var $row = -1; // a row counter, needed to loop through records in postgres.
var $result = null; // point to result set.
var $errorCode = 0; // internal error code
////////////////////////////////////////////
// Core primary connection/database function
////////////////////////////////////////////
// Set appropriate parameters for database connection
function set_db_info($DataBaseReference){
switch ($DataBaseReference){
case "someName":
$this->hostName = "localhost";
$this->port = "5432";
$this->userName = "nobody" ;
$this->password = "";
$this->databaseName = "someDBname";
break;
case "test":
$this->hostName = "";
$this->port = "";
$this->userName = "";
$this->password = "" ;
$this->databaseName = "test";
break;
default:
// FATAL ERROR - DB REFERENCE UNDEFINED
}
}
// connection function
function connect($DataBaseReference){
if (isset($DataBaseReference)) {
$this->set_db_info($DataBaseReference);
// build connection string based on internal settings.
$connStr = '';
($this->hostName != '') ? ($connStr .= "host=" . $this->hostName . " ") : ($connStr = $connStr);
($this->port != '') ? ($connStr .= "port=" . $this->port . " ") : ($connStr = $connStr);
($this->databaseName != '') ? ($connStr .= "dbname=" . $this->databaseName . " ") : ($connStr = $connStr);
($this->userName != '') ? ($connStr .= "user=" . $this->userName . " ") : ($connStr = $connStr);
($this->password != '') ? ($connStr .= "password=" . $this->password . " ") : ($connStr = $connStr);
$connStr = trim($connStr);
$connID = @pg_connect($connStr);
if ($connID != "") {
$this->connectionID = $connID;
$this->exec("set datestyle='ISO'");
$this->exec("set time zone 'PST'");
return $this->connectionID ;
} else {
// FATAL ERROR - CONNECTI0N ERROR
$this->errorCode = -1;
$this->connectionID = -1;
return 0;
}
} else {
// FATAL ERROR - FUNCTION CALLED WITH NO PARAMETERS
$this->connectionID = -1;
return 0;
}
}
// standard method to close connection
function close() {
if ($this->connectionID != "-1") {
$this->RollbackTrans(); // rollback transaction before closing
$closed = pg_close($this->connectionID);
return $closed;
} else {
// connection does not exist
return null;
}
}
// function to execute sql queries
function exec($query){
if ($this->connectionID != "-1") {
$this->result = @pg_exec($this->connectionID, $query);
if ($this->numRows() > 0) $this->moveFirst();
return $this->result;
}
else return 0;
}
// get last error message for db connection
function errorMsg() {
if ($this->connectionID == "-1") {
switch ($this->errorCode) {
case -1:
return "FATAL ERROR - CONNECTION ERROR: RESOURCE NOT FOUND";
break;
case -2:
return "FATAL ERROR - CLASS ERROR: FUNCTION CALLED WITHOUT PARAMETERS";
break;
default:
return null;
}
} else {
return pg_errormessage($this->connectionID);
}
}
////////////////////
// Cursor movement
////////////////////
// move pointer to first row of result set
function moveFirst() {
if ($this->result == null) return false;
else {
$this->setRow(0);
return true;
}
}
// move pointer to last row of result set
function moveLast() {
if ($this->result == null) return false;
else {
$this->setRow($this->numRows()-1);
return true;
}
}
// point to the next row, return false if no next row
function moveNext() {
// If more rows, then advance row pointer
if ($this->row < $this->numRows()-1) {
$this->setRow($this->row +1);
return true;
}
else return false;
}
// point to the previous row, return false if no previous row
function movePrevious() {
// If not first row, then advance row pointer
if ($this->row > 0) {
$this->setRow($this->row -1);
return true;
}
else return false;
}
// point to the next row, return false if no next row
function nextRow() {
// If more rows, then advance row pointer
if ($this->row < $this->numRows()-1) {
$this->setRow($this->row +1);
return true;
}
else return false;
}
// can be used to set a pointer to a perticular row
function setRow($row){
$this->row = $row;
}
///////////////////////
// Result set related
///////////////////////
// used to pull the results back
function fobject() {
if ($this->result == null || $this->row == "-1") return null;
else {
$object = pg_fetch_object($this->result,$this->row);
return $object;
}
}
// another method to obtain results
function farray(){
if ($this->result == null || $this->row == "-1") return null;
else {
$arr = pg_fetch_array($this->result,$this->row);
return $arr;
}
}
// return number of affected rows by a DELETE, UPDATE, INSERT
function numAffected() {
if ($this->result == null) return 0; // no result to return result from!
else return pg_cmdtuples ($this->result);
}
// get the number of rows in a result
function numRows(){
if ($this->result == null) return 0;
else {
$this->numrows = pg_numrows($this->result);
return $this->numrows;
}
}
// return current row
function currRow(){
return $this->row;
}
function recordCount() {
return $this->numRows();
}
// get the number of fields in a result
function numFields() {
if ($this->result == null) return 0;
else return pg_numfields ($this->result);
}
function columnCount() {
return $this->numFields();
}
// get last OID (object identifier) of last INSERT statement
function lastOID() {
if ($this->result == null) return null;
else return pg_getlastoid ($this->result);
}
// get result field name
function fieldname($fieldnum) {
if ($this->result == null) return null;
else return pg_FieldName($this->result, $fieldnum);
}
////////////////////////
// Transaction related
////////////////////////
function beginTrans() {
return @pg_exec($this->connectionID, "begin");
}
function commitTrans() {
return @pg_exec($this->connectionID, "commit");
}
// returns true/false
function rollbackTrans() {
return @pg_exec($this->connectionID, "rollback");
}
////////////////////////
// SQL String Related
////////////////////////
function querySafe($string) {
// replace ' with '
$string = str_replace("'", "'", $string);
// replace line-break characters
$string = str_replace("n", "", $string);
$string = str_replace("r", "", $string);
return $string;
}
function sqlSafe($string) {
// replace ' with ''
// use this function only for text fields that may contain "'"'s
$string = str_replace("'", "''", $string);
return $string;
}
} // end class phpDB
?>
|
|
|
Usage Example
|
//// Example #1 ////////////////
include("include/dblib.php");
$db = new phpDB();
$db->connect("foobar");
$db->beginTrans();
if (!$db->exec("INSERT INTO weather VALUES ('Vancouver', 1, 5, 0.25)")) {
echo $db->errorMsg();
$db->rollbackTrans();
}
$db->commitTrans();
if (!$db->exec("SELECT * FROM weather"))
echo $db->errorMsg();
//// Example #2 ////////////////
include("include/dbutil.php");
$db = new phpDB();
$db->connect("foobar");
$db->exec("SELECT * from TREVIN");
while ($db->nextRow()) {
// can access like objects!
$rs1 = $db->fobject();
echo "$rs->description : $rs->color : $rs->price <br>";
// Can access like an array!
$rs2 = $db->farray();
echo "$rs2[0] : $rs2[1] : $rs[2] <br>";
}
|
|
|
Rate This Script
|
|
|
|
Store
Your email: