在动态网面设计中很多都要涉及到对数据库的操作,但是有时跟据需要而改用其它后台数据库，就需要大量修改程序。这是一件枯燥、费时而且容易出错的功作。其实我们可以用PHP中的类来实现对数据库操作的封装，从而使写出的程序在很小的改动下就可以完成后台数据库的更改。
<?
class dbInterface{ var $dbID=1; //用于确定当前操作的数据库，当dbID为1代表MySql,当为 2代表 SQL Server，为3时为ODBC或其它。
var $dbHost; //数据库所在主机域名
var $dbUsername; //数据库用户名
var $dbPassword; //用户密码
//设置主机、用户名及密码函数
function setParameter($host,$username,$password){
$this->dbUsername=$username;
$this->dbHost=$host;
$this->dbPassword=$password;
} //联接数库函数
function dbConnect(){
switch($this->dbID)
{
case 1;
return @mysql_connect($this->dbHost,$this->dbUsername,$this->dbPassword);
case 2;
//用支持SQL Server的函数
case 3;
//用支持ODBC的函数
}
}
//关闭数库函数
function dbClose($dataHandle){
switch($this->dbID)
{
case 1;
mysql_close($dataHandle);
case 2;
//用支持SQL Server的函数
case 3;
//用支持ODBC的函数
}
}
//执行SQL语句函数
function dbQuery($dbName,$sql,$dbHandle){
switch($this->dbID)
{
case 1;
return @mysql_db_query($dbName,$sql,$dbHandle);
case 2;
//用支持SQL Server的函数
case 3;
//用支持ODBC的函数
}
}
//检索SQL返回值的当前记录函数
function dbFetchrow($dataHandle,$offset=-1){
switch($this->dbID)
{
case 1;
@mysql_data_seek($dataHandle,$offset);
return @mysql_fetch_row($dataHandle);
case 2;
//用支持SQL Server的函数
case 3;
//用支持ODBC的函数
}
}
//返回检索记录数函数
function dbNumrows($dataHandle){
switch($this->dbID)
{
case 1;
return @mysql_num_rows($dataHandle);
case 2;
//用支持SQL Server的函数
case 3;
//用支持ODBC的函数
}
}
//返回检索列数函数
function dbNumcols($dataHandle){
switch($this->dbID)
{
case 1;
return @mysql_num_fields($dataHandle);
case 2;
//用支持SQL Server的函数
case 3;
//用支持ODBC的函数
}
}
}
现把使用说明如下：
在程序中用dbInterface类生一个对象$test=new dbInterface;
设置参数
test->$dbUsername ;用户名
test->$dbPassword；密码
test->$dbHost；主机
void setParameter(string host, string username, string password);
数据库连接：dbhandle test->dbConnect();
返回值：fasle ，数据库连接错误
>0, 数据库连接句柄
数据库关闭：void test->dbClose(dbhandle);
表操作：int test->dbQuery(string databasename, string sql，dbhandle);执行SQL语句
返回值： false， SQL执行错误
>0, SQL执行正确, 同时指向SQL返回值，
数据操作：int test->dbFetchrow(dataHandle，int offset);检索SQL返回值的当前记录，成功执行后，指针移向下一条记录
int test->dbNumrows(dataHandle); 取得SQL执行后（主要为SELECT语句）获得的记录数
int test->dbNumcols(dataHandle); 取得SQL执行后（主要为SELECT语句）获得的记录字段数
现在我们发一个例了讲解：
数据库采用MQSQL:其主机名为 "localhost",用户名为"root"和密码""。
-----
<HTML><HEAD>
<TITLE>test</TITLE>
</HEAD><BODY>
<P> <?php
require("testdb.inc"); //装载dbInterface类
$test = new dbInterface;//用类dbInterface生成一个对象
$test->setParameter("localhost","root","")；//设置数据库参数
$db = $test->dbConnect();//连接数据库
$Query = "SELECT name,pay FROM table ";//设置SQL语句
$temp_result = $test->dbQuery("testdb",$Query,$db)；//执行数据主库操作
echo "<br>";
$ls_num = $test->dbNumrows($temp_result); //取得查询结果的记录数
echo $ls_num;
echo "<br>";
if (ls_num>0 )
{
$ls_col = $test->dbNumcols($db); //取得表的列数
echo $ls_col;
echo "<br>";
$cate_result=$test->dbFetchrow($temp_result,0);//取得记录数的第一行
$hcid=$cate_result[0];// 取得name的值
$hcate=$cate_result[1];//取得pay的值
echo $hcid;
echo "<br>";
echo $hcate;
}
?>
<HR>
<ADDRESS></ADDRESS>
</BODY></HTML>
在mysql中有一个testdb数据库及其中的表table1,表包括:name和pay两个字段
php封装一个class类实现mysql数据库的增删该查
<?php
Class DB {
private $link_id;
private $handle;
private $is_log;
private $time;
//构造函数
public function __construct() {
$this->time = $this->microtime_float();
require_once("config.db.php");
$this->connect($db_config["hostname"], $db_config["username"], $db_config["password"], $db_config["database"], $db_config["pconnect"]);
$this->is_log = $db_config["log"];
if($this->is_log){
$handle = fopen($db_config["logfilepath"]."dblog.txt", "a+");
$this->handle=$handle;
}
}
//数据库连接
public function connect($dbhost, $dbuser, $dbpw, $dbname, $pconnect = 0,$charset='utf8') {
if( $pconnect==0 ) {
$this->link_id = @mysql_connect($dbhost, $dbuser, $dbpw, true);
if(!$this->link_id){
$this->halt("数据库连接失败");
}
} else {
$this->link_id = @mysql_pconnect($dbhost, $dbuser, $dbpw);
if(!$this->link_id){
$this->halt("数据库持久连接失败");
}
}
if(!@mysql_select_db($dbname,$this->link_id)) {
$this->halt('数据库选择失败');
}
@mysql_query("set names ".$charset);
}
//查询
public function query($sql) {
$this->write_log("查询 ".$sql);
$query = mysql_query($sql,$this->link_id);
if(!$query) $this->halt('Query Error: ' . $sql);
return $query;
}
//获取一条记录（MYSQL_ASSOC，MYSQL_NUM，MYSQL_BOTH）
public function get_one($sql,$result_type = MYSQL_ASSOC) {
$query = $this->query($sql);
$rt =& mysql_fetch_array($query,$result_type);
$this->write_log("获取一条记录 ".$sql);
return $rt;
}
//获取全部记录
public function get_all($sql,$result_type = MYSQL_ASSOC) {
$query = $this->query($sql);
$i = 0;
$rt = array();
while($row =& mysql_fetch_array($query,$result_type)) {
$rt[$i]=$row;
$i++;
}
$this->write_log("获取全部记录 ".$sql);
return $rt;
}
//插入
public function insert($table,$dataArray) {
$field = "";
$value = "";
if( !is_array($dataArray) || count($dataArray)<=0) {
$this->halt('没有要插入的数据');
return false;
}
while(list($key,$val)=each($dataArray)) {
$field .="$key,";
$value .="'$val',";
}
$field = substr( $field,0,-1);
$value = substr( $value,0,-1);
$sql = "insert into $table($field) values($value)";
$this->write_log("插入 ".$sql);
if(!$this->query($sql)) return false;
return true;
}
//更新
public function update( $table,$dataArray,$condition="") {
if( !is_array($dataArray) || count($dataArray)<=0) {
$this->halt('没有要更新的数据');
return false;
}
$value = "";
while( list($key,$val) = each($dataArray))
$value .= "$key = '$val',";
$value .= substr( $value,0,-1);
$sql = "update $table set $value where 1=1 and $condition";
$this->write_log("更新 ".$sql);
if(!$this->query($sql)) return false;
return true;
}
//删除
public function delete( $table,$condition="") {
if( empty($condition) ) {
$this->halt('没有设置删除的条件');
return false;
}
$sql = "delete from $table where 1=1 and $condition";
$this->write_log("删除 ".$sql);
if(!$this->query($sql)) return false;
return true;
}
//返回结果集
public function fetch_array($query, $result_type = MYSQL_ASSOC){
$this->write_log("返回结果集");
return mysql_fetch_array($query, $result_type);
}
//获取记录条数
public function num_rows($results) {
if(!is_bool($results)) {
$num = mysql_num_rows($results);
$this->write_log("获取的记录条数为".$num);
return $num;
} else {
return 0;
}
}
//释放结果集
public function free_result() {
$void = func_get_args();
foreach($void as $query) {
if(is_resource($query) && get_resource_type($query) === 'mysql result') {
return mysql_free_result($query);
}
}
$this->write_log("释放结果集");
}
//获取最后插入的id
public function insert_id() {
$id = mysql_insert_id($this->link_id);
$this->write_log("最后插入的id为".$id);
return $id;
}
//关闭数据库连接
protected function close() {
$this->write_log("已关闭数据库连接");
return @mysql_close($this->link_id);
}
//错误提示
private function halt($msg='') {
$msg .= "
".mysql_error();
$this->write_log($msg);
die($msg);
}
//析构函数
public function __destruct() {
$this->free_result();
$use_time = ($this-> microtime_float())-($this->time);
$this->write_log("完成整个查询任务,所用时间为".$use_time);
if($this->is_log){
fclose($this->handle);
}
}
//写入日志文件
public function write_log($msg=''){
if($this->is_log){
$text = date("Y-m-d H:i:s")." ".$msg."
";
fwrite($this->handle,$text);
}
}
//获取毫秒数
public function microtime_float() {
list($usec, $sec) = explode(" ", microtime());
return ((float)$usec + (float)$sec);
}
}
?>
<?php
Class DB {
private $link_id;
private $handle;
private $is_log;
private $time;
//构造函数
public function __construct() {
$this->time = $this->microtime_float();
require_once("config.db.php");
$this->connect($db_config["hostname"], $db_config["username"], $db_config["password"], $db_config["database"], $db_config["pconnect"]);
$this->is_log = $db_config["log"];
if($this->is_log){
$handle = fopen($db_config["logfilepath"]."dblog.txt", "a+");
$this->handle=$handle;
}
}
//数据库连接
public function connect($dbhost, $dbuser, $dbpw, $dbname, $pconnect = 0,$charset='utf8') {
if( $pconnect==0 ) {
$this->link_id = @mysql_connect($dbhost, $dbuser, $dbpw, true);
if(!$this->link_id){
$this->halt("数据库连接失败");
}
} else {
$this->link_id = @mysql_pconnect($dbhost, $dbuser, $dbpw);
if(!$this->link_id){
$this->halt("数据库持久连接失败");
}
}
if(!@mysql_select_db($dbname,$this->link_id)) {
$this->halt('数据库选择失败');
}
@mysql_query("set names ".$charset);
}
//查询
public function query($sql) {
$this->write_log("查询 ".$sql);
$query = mysql_query($sql,$this->link_id);
if(!$query) $this->halt('Query Error: ' . $sql);
return $query;
}
//获取一条记录（MYSQL_ASSOC，MYSQL_NUM，MYSQL_BOTH）
public function get_one($sql,$result_type = MYSQL_ASSOC) {
$query = $this->query($sql);
$rt =& mysql_fetch_array($query,$result_type);
$this->write_log("获取一条记录 ".$sql);
return $rt;
}
//获取全部记录
public function get_all($sql,$result_type = MYSQL_ASSOC) {
$query = $this->query($sql);
$i = 0;
$rt = array();
while($row =& mysql_fetch_array($query,$result_type)) {
$rt[$i]=$row;
$i++;
}
$this->write_log("获取全部记录 ".$sql);
return $rt;
}
//插入
public function insert($table,$dataArray) {
$field = "";
$value = "";
if( !is_array($dataArray) || count($dataArray)<=0) {
$this->halt('没有要插入的数据');
return false;
}
while(list($key,$val)=each($dataArray)) {
$field .="$key,";
$value .="'$val',";
}
$field = substr( $field,0,-1);
$value = substr( $value,0,-1);
$sql = "insert into $table($field) values($value)";
$this->write_log("插入 ".$sql);
if(!$this->query($sql)) return false;
return true;
}
//更新
public function update( $table,$dataArray,$condition="") {
if( !is_array($dataArray) || count($dataArray)<=0) {
$this->halt('没有要更新的数据');
return false;
}
$value = "";
while( list($key,$val) = each($dataArray))
$value .= "$key = '$val',";
$value .= substr( $value,0,-1);
$sql = "update $table set $value where 1=1 and $condition";
$this->write_log("更新 ".$sql);
if(!$this->query($sql)) return false;
return true;
}
//删除
public function delete( $table,$condition="") {
if( empty($condition) ) {
$this->halt('没有设置删除的条件');
return false;
}
$sql = "delete from $table where 1=1 and $condition";
$this->write_log("删除 ".$sql);
if(!$this->query($sql)) return false;
return true;
}
//返回结果集
public function fetch_array($query, $result_type = MYSQL_ASSOC){
$this->write_log("返回结果集");
return mysql_fetch_array($query, $result_type);
}
//获取记录条数
public function num_rows($results) {
if(!is_bool($results)) {
$num = mysql_num_rows($results);
$this->write_log("获取的记录条数为".$num);
return $num;
} else {
return 0;
}
}
//释放结果集
public function free_result() {
$void = func_get_args();
foreach($void as $query) {
if(is_resource($query) && get_resource_type($query) === 'mysql result') {
return mysql_free_result($query);
}
}
$this->write_log("释放结果集");
}
//获取最后插入的id
public function insert_id() {
$id = mysql_insert_id($this->link_id);
$this->write_log("最后插入的id为".$id);
return $id;
}
//关闭数据库连接
protected function close() {
$this->write_log("已关闭数据库连接");
return @mysql_close($this->link_id);
}
//错误提示
private function halt($msg='') {
$msg .= "
".mysql_error();
$this->write_log($msg);
die($msg);
}
//析构函数
public function __destruct() {
$this->free_result();
$use_time = ($this-> microtime_float())-($this->time);
$this->write_log("完成整个查询任务,所用时间为".$use_time);
if($this->is_log){
fclose($this->handle);
}
}
//写入日志文件
public function write_log($msg=''){
if($this->is_log){
$text = date("Y-m-d H:i:s")." ".$msg."
";
fwrite($this->handle,$text);
}
}
//获取毫秒数
public function microtime_float() {
list($usec, $sec) = explode(" ", microtime());
return ((float)$usec + (float)$sec);
}
}