数据库操作类

<?php            //数据库操作类
 
if(!defined('SQL_LAYER'))
{
    define('SQL_LAYER',"mysql");
 
    class sql_db
    {
        var $db_connect_id;
        var $query_result;
        var $row=array();
        var $rowset=array();
        var $num_queries=0;
 
        function __construct($sqlserver,$sqluser,$sqlpassword,$database,$persistency=true)
        {
            $this->persistency=$persistency;
            $this->user=$sqluser;
            $this->password=$sqlpassword;
            $this->server=$sqlserver;
            $this->dbname=$database;
 
            if($this->persistency)
            {
                $this->db_connect_id=mysql_pconnect($this->server,$this->user,$this->password);
            }
            else
            {
                $this->db_connect_id=mysql_connect($this->server,$this->user,$this->password);
            }
            if($this->db_connect_id)
            {
                if($database!="")
                {
                    $this->dbname=$database;
                    $dbselect=mysql_select_db($this->dbname);
                    if(!$dbselect)
                    {
                        mysql_close($this->db_connect_id);
                        $this->db_connect_id=$dbselect;
                    }
                }
                return $this->db_connect_id;
 
            }
            else
            {
                return false;
            }
        }
 
        //其他基本方法
        function sql_close()//关闭数据库
        {
            if($this->db_connect_id)
            {
                if($this->query_result)
                {
                    //mysql_free_result() 仅需要在考虑到返回很大的结果集时会占用多少内存时调用。
                    //在脚本结束后所有关联的内存都会被自动释放。
                    mysql_free_result($this->query_result);
                }
 
                //关闭数据库
                $result=mysql_close($this->db_connect_id);
                return $result;
            }
            else
            {
                return false;
            }
        }
 
        //SQL语句执行函数
        function sql_query($query="",$transaction=FALSE)
        {
            //释放内存
            unset($this->query_result);
            if($query!="")
            {
                $this->num_queries++;
                $this->query_result=mysql_query($query,$this->db_connect_id);
            }
            if($this->query_result)
            {
                //如果存在查询结果，则释放内存
                unset($this->row[$this->query_result]);
                unset($this->rowset[$this->query_result]);
                return $this->query_result;
            }
            else
            {
                return ($transaction==END_TRANSACTION) ? true : false;
            }
        }
 
        //定义获取数据的行数
        function sql_numrows($query_id=0)
        {
            if(!$query_id)
            {
                $query_id=$this->query_result;
            }
            if($query_id)
            {
                $result=mysql_num_rows($query_id);
                return $result;
            }
            else
            {
                return false;
            }
        }
 
        //取得前一次 MySQL 操作所影响的记录行数
        function sql_affectedrows()
        {
            if($this->db_connect_id)
            {
                $result=mysql_affected_rows($this->db_connect_id);
                return $result;
            }
            else
            {
                return false;
            }
        }
 
        //取得结果集中字段的数目
        function sql_numfields($query_id=0)
        {
            if(!$query_id)
            {
                $query_id=$this->query_result;
            }
            if($query_id)
            {
                $result=mysql_num_fields($query_id);
                return $result;
            }
            else
            {
                return false;
            }
        }
 
        //获取结果中指定字段的字段名
        function sql_fieldname($offset,$query_id=0)
        {
            if(!$query_id)
            {
                $query_id=$this->query_result;
            }
            if($query_id)
            {
                $result=mysql_field_name($query_id,$offset);
                return $result;
            }
            else
            {
                return false;
            }
 
        }
 
        //获取结果集中指定字段的类型
        function sql_fieldtype($offset,$query_id=0)
        {
            if(!$query_id)
            {
                $query_id=$this->query_result;
            }
            if($query_id)
            {
                $result=mysql_field_type($query_id,$offset);
                return $result;
            }
            else
            {
                return false;
            }
        }
 
        function sql_fetchrow($query_id=0)
        {
            if(!$query_id)
            {
                $query_id=$this->query_result;
            }
            if($query_id)
            {
                $this->row[$query_id]=mysql_fetch_array($query_id);
                return $this->row[$query_id];
            }
            else
            {
                return false;
            }
        }
 
        function sql_fetchrowset($query_id = 0)
        {
            if(!$query_id)
            {
                $query_id = $this->query_result;
            }
            if($query_id)
            {
                unset($this->rowset[$query_id]);
                unset($this->row[$query_id]);
                while($this->rowset[$query_id] = @mysql_fetch_array($query_id))
                {
                    $result[] = $this->rowset[$query_id];
                }
                return $result;
            }
            else
            {
                return false;
            }
        }
 
        function sql_fetchfield($field, $rownum = -1, $query_id = 0)
        {
            if(!$query_id)
            {
                $query_id = $this->query_result;
            }
            if($query_id)
            {
                if($rownum > -1)
                {
                    //取得结果的值
                    $result = @mysql_result($query_id, $rownum, $field);
                }
                else
                {
                    if(empty($this->row[$query_id]) && empty($this->rowset[$query_id]))
                    {
                        if($this->sql_fetchrow())
                        {
                            $result = $this->row[$query_id][$field];
                        }
                    }
                    else
                    {
                        if($this->rowset[$query_id])
                        {
                            $result = $this->rowset[$query_id][0][$field];
                        }
                        else if($this->row[$query_id])
                        {
                            $result = $this->row[$query_id][$field];
                        }
                    }
                }
                return $result;
            }
            else
            {
                return false;
            }
        }
 
        //行选择函数
        function sql_rowseek($rownum, $query_id = 0)
        {
            if(!$query_id)
            {   //获取$query_id的值
                $query_id = $this->query_result;
            }
            if($query_id)
            {
                //移动内部结果的指针
                $result = @mysql_data_seek($query_id, $rownum);
                return $result;
            }
            else
            {
                return false;
            }
        }
 
        function sql_nextid()
        {
            if($this->db_connect_id)
            {   //取得上一步 INSERT 操作产生的 ID
                $result = @mysql_insert_id($this->db_connect_id);
                return $result;
            }
            else
            {
                return false;
            }
        }
 
        function sql_freeresult($query_id=0)
        {
            if(!$query_id)
            {
                $query_id=$this->query_result;
            }
            if($query_id)
            {
                //释放给定的变量的内存
                unset($this->row[$query_id]);
                unset($this->rowset[$query_id]);
                //释放内存
                mysql_free_result($query_id);
                return true;
            }
            else
            {
                return false;
            }
        }
 
        //SQL语句执行错误的函数
        function sql_error($query_id=0)
        {
            $result["message"]=mysql_error($this->db_connect_id);
 
            $result["code"]=mysql_errno($this->db_connect_id);
            return $result;
        }
 
 
    }
}
 
?>