php数据库操作类，实现表的增删改查，获取行数，查询多条数据记录，左连接查询，创建数据表结构等。功能丰富，方便移值，有需要的朋友，可以参考下。php数据库类完整代码与示例如下。
1、代码
links = mysql_connect(db_host, db_user, db_pwd);if(debug){mysql_select_db(db_name) or die('error:'.mysql_error());}else{mysql_select_db(db_name);}$char_sql = set names ' . charset . ';$this->query($char_sql);}/*** ****************** 操作 *******************//*** 增删改查操作方法* 输入sql语句* 返回布尔值或结果集$row*/function query($sql) {if(debug){$render = mysql_query($sql) or die('query error:'.mysql_error().
sql语句出错： . $sql);return $render;}else{return mysql_query($sql);}}/*** 计算行数方法* 输入* 结果数组*/function count($table,$condition='1') {$sql = select count(*) from `.db_prefix.$table.` where $condition;$result = $this->select($sql);return $result[0]['count(*)'];}/*** 原始的sql语句查操作方法* 输入sql语句* 结果数组*/function select($sql) {$row = $this->query($sql);$results = array();while($arr = $this->fetch($row)){$results[] = $arr;}//$this->free_result($row);return $results;}/*** 检查某字段是否存在某值* @param 输入表名.字段,值* @return id 或者 false**/function check_exists($table,$val){$render = false;$tab = explode('.',$table);if($tab['1'] && $tab['1']!='id'){$fields = $tab['1'];$table = {$tab[0]}.id,{$fields};}else{$fields = 'id';$table = $tab[0]..id;}$condition = `$fields` = '{$val}';$detail = $this->read($table,$condition);if($detail[$fields]){$render = $detail['id'];}return $render;}/*** 查询多条数据方法* 输入表名.字段，字段;查询条件，条数* 如果条件是数组，则进入高级搜索模式* 返回结果数组*/function readall($table,$condition='1',$limit='') {$tab = explode('.',$table);$table = $tab['0'];if($tab['1']){$fields = $tab['1'];$fields_array =explode(',',$fields);$fields = '';foreach( $fields_array as $one){$fields .= `$one`,;}$fields = rtrim($fields,',');}else{$fields = '*';}if(is_array($condition)){$condition = $this->parse_condition($condition);}$sql = select $fields from `.db_prefix.$table.` where $condition;if($limit)$sql .= limit $limit;return $this->select($sql);}/*** 查询单条数据方法* 输入表名.字段，字段;查询条件* 返回结果数组*/function read($table,$condition='1') {$render = $this ->readall($table,$condition,1);return $render[0];}/*** 修改数据方法* 输入表名，插入数据array('字段'=>'值'),条件* 返回布尔值*/function update($table,$data,$condition ) {$set = '';foreach( $data as $key=>$val){$set .= `$key` = '.$val.',;}$set = rtrim($set,',');if(is_array($condition)){$condition = $this->parse_condition($condition);}$sql = update `.db_prefix.$table.` set $set where $condition;return $this->query($sql);}/*** 插入数据方法* 输入表名，数据array('字段'=>'值')* 返回布尔*/function insert($table,$data) {$fields = array();$values = array();foreach( $data as $key=> $val){if(is_array($val)){$_values = array();$_fields = array();foreach( $val as $k=> $v){$_fields[]= `$k`;$_values[]= '{$v}';}$fields = $_fields;$values[] = '('.implode(',',$_values).')';}else{$fields[] = `$key`;$values[] = '{$val}';}}$fields = implode(',',$fields);$values = implode(',',$values);$sql = insert into `.db_prefix.$table.` ($fields) values($values);return $this->query($sql);}/*** 删除数据方法* 输入表名，条件* 返回bool*/function delete($table,$condition) {if(empty($condition)){die('条件不能为空');}if(is_array($condition)){$condition = $this->parse_condition($condition);}$sql = delete from `.db_prefix.$table.` where $condition;return $this->query($sql);}/*** 解析条件的函数* @param 条件数组* $arr[] = `id`==0;$arr[] = `id`==5;$arr['id'] = 5;$arr['or'][] = `id`!=2;$arr['or'][] = `id`!=1;$arr['or'][] = `id`!=2;$arr['groups'][]='id';$arr['orders']['id']='asc';$arr['orders']['td']='desc';* * @return str**/function parse_condition($condition){$and = '1';$or = '0';$groups = array();$orders = array();foreach( $condition as $key=>$val){if(is_numeric($key)){$and .= and $val;}elseif(strtolower($key)== 'or'){//处理or条件if(is_array($val)){foreach( $val as $k=>$v){if(is_numeric($k)){$or .= or {$v};}elseif(is_array($v)){$v = implode(',',$v);$or .= or `$k` in ($v);}else{$or .= or `$k='{$v}';}}}else{$or .= or $val';}}elseif(strtolower($key)== 'groups'){//处理group byforeach( $val as $k=>$v){$groups[] = $v;}}elseif(strtolower($key)== 'orders'){//处理order byforeach( $val as $k=>$v){$orders[] = $k.' '.$v;}}else{if(is_array($val)){$val = implode(',',$val);$and .= and `$key` in ($val);}else{$and .= and `$key`='{$val}';}}}if($and!='1' && $or!='0')$where = $and.' or '.$or;elseif($and!='1') $where = $and;elseif($or!='0') $where = $or;if($groups)$where .= group by .implode(',',$groups);if($orders)$where .= order by .implode(',',$orders);$where = str_replace('1 and','',str_replace('0 or','',$where));return $where;}/*** 锁表方法* 输入表名，锁定类型，r or w 写锁要放在读锁前面* 返回bool*/function lock($table,$type='r') {if($type=='r'){$type = 'read';}else{$type = 'write';}$sql = lock table `.db_prefix.$table.` $type;return $this->query($sql);}/*** 解锁表方法** 返回bool*/function unlock( ) {$sql = unlock tables;return $this->query($sql);}/*** 结果集放入数组方法* 返回数组，指针下移*/function fetch($row) {return mysql_fetch_array($row,mysql_assoc);}/*** 计算结果集行数方法* 输入$row* 返回行数*/function num_rows($row) {return mysql_num_rows($row);}/*** 计算结果集列数方法* 输入$row* 返回列数*/function num_fields($row) {return mysql_num_fields($row);}/*** 释放result结果集内存* 返回布尔值*/function free_result($row) {return mysql_free_result($row);}/*** 查看指定表的字段名* 输入表名* 返回全部字段名数组*/function list_fields($table) {$fields = mysql_list_fields(db_name, db_prefix.$table, $this->links);$columns = mysql_num_fields($fields);for ($i = 0; $i readall($table,$condition,$limit);//取得结果集行数$num = $this->count($table,$condition);//定义最后页 $maxpageif ($num % $pagesize) {$maxpage = (int) ($num / $pagesize +1);} else$maxpage = $num / $pagesize;if(statics){//从服务器端取得url信息if($_get[$id] === null){$_server[request_uri] = str_replace('index.php','',$_server[request_uri]);$_session[$id] = str_replace('.html','',$_server[request_uri],$count);$_session[$id] = $count?$_session[$id] :$_session[$id].'index';if(!sizeof($_get))$_session[$id].=-htm;}$str = first ;if($page)$str .= previous ;if($page-3>=0)$str .=.($page-2). ;if($page-2>=0)$str .=.($page-1). ;if($page-1>=0)$str .=.$page. ;if($page < $maxpage)$str .=($page+1). ;if($page+1 < $maxpage)$str .=.($page+2). ;if($page+2 < $maxpage)$str .=.($page+3). ;if($page+3 =0)$str .=.($page-1). ;if($page-1>=0)$str .=.$page. ;if($page < $maxpage)$str .=($page+1). ;if($page+1 < $maxpage)$str .=.($page+2). ;if($page+2 < $maxpage)$str .=.($page+3). ;if($page+3 $sql
;}exit;}};?>调用示例：
createtable('article',$data,'文章表');//增删改查$data['title']='t';$data['keyword']='k';$db->insert('article',$data);$num = $db->read('article.id','1 order by id desc');$data['created'] = mktime()+$num['id'];$db->update('article',$data,`id` =2);$db->delete('article',`id` =3);?>