非常好的class
<?
class DB_Sql {
var $Host = 'localhost'; //主机名称
var $Database = 'test'; //数据库名称
var $User = 'root'; //用户名
var $Password = ''; //用户密码
/* public: configuration parameters */
var $Auto_Free = 0; // 如果非0就自动释放Mysql
var $Debug = 0; // 如果非0就显示调试信息
var $Halt_On_Error = 'yes'; // "yes"(halt with message),"no"(ignore errors quietly),"report"(ignore errror, but spit a warning)
var $Seq_Table = 'db_sequence';
var $Record = array();
var $Row;
var $Errno = 0;
var $Error = '';
/* 本MySQL操作库的版本. */
var $type = "mysql";
var $revision = "1.0CVersion";
var $Link_ID = 0;
var $Query_ID = 0;
/* 下面开始过程部分 */
/* 默认连接 */
function DB_SQL($Database = '', $Host = '', $User = '', $Password = '') {
$this->connect($Database, $Host, $User, $Password);
}
/* 返回连接指针 */
function link_id() {
return $this->Link_ID;
}
/* 返回查询指针 */
function query_id() {
return $this->Query_ID;
}
/* 连接MySQL数据库 */
function connect($Database = '', $Host = '', $User = '', $Password = '') {
if ('' <> $Database) $this->Database = $Database;
if ('' <> $Host) $this->Host = $Host;
if ('' <> $User) $this->User = $User;
if ('' <> $Password) $this->Password = $Password;
if ( 0 == $this->Link_ID ) {
$this->Link_ID=mysql_pconnect($this->Host, $this->User, $this->Password);
if (!$this->Link_ID) {
$this->halt("MySQLpConnect($this->Host, $this->User, \$this->Password) failed.");
return false;
}
if (!@mysql_select_db($this->Database,$this->Link_ID)) {
$this->halt("Cannot use database ".$this->Database);
return false;
}
}
return $this->Link_ID;
}
/* 释放MySQL函数 */
function free() {
@mysql_free_result($this->Query_ID);
$this->Query_ID = 0;
}
/* MySQL查询 */
function query($Query_String) {
if ($Query_String == '') return false;
if (!$this->connect()) return false;
if ($this->Query_ID) $this->free();
if ($this->Debug) printf("Debug: query = %s<br>\n", $Query_String);
$this->Query_ID = @mysql_query($Query_String,$this->Link_ID);
$this->Row = 0;
$this->Errno = mysql_errno();
$this->Error = mysql_error();
if (!$this->Query_ID) $this->halt("Invalid SQL: ".$Query_String);
return $this->Query_ID;
}
/* 把结果指针往前推进 */
function next_record() {
if (!$this->Query_ID) {
$this->halt("Next_record called with no query pending.");
return false;
}
$this->Record = @mysql_fetch_array($this->Query_ID);
$this->Errno = mysql_errno();
$this->Error = mysql_error();
$this->Row++;
$stat = is_array($this->Record);
if (!$stat && $this->Auto_Free) $this->free();
return $stat;
}
/* 偏移指针 */
function seek($pos = 0) {
$status = @mysql_data_seek($this->Query_ID, $pos);
if ($status) $this->Row = $pos;
else {
$this->halt("Seek($pos) failed: result has ".$this->num_rows()." rows");
@mysql_data_seek($this->Query_ID, $this->num_rows());
$this->Row = $this->num_rows;
return false;
}
return true;
}
/*----------------------------------------------*
* 锁表格：注意 *
* 本表格可以是一个数组 *
* 如果是数组就会把所有数组元素当作表格来处理 *
*--------------------------------------------- */
function lock($table, $mode='write') {
$this->connect();
$query='lock tables ';
if (is_array($table)) {
while (list($key,$value)=each($table)) {
if ($key=='read' && $key!=0) {
$query.="$value read, ";
} else {
$query.="$value $mode, ";
}
}
$query = substr($query,0,-2);
} else {
$query.="$table $mode";
}
$res = @mysql_query($query, $this->Link_ID);
if (!$res) {
$this->halt("lock($table, $mode) failed.");
return false;
}
return $res;
}
/* 表格解锁 */
function unlock() {
$this->connect();
$res = @mysql_query("unlock tables");
if (!$res) {
$this->halt("unlock() failed.");
return false;
}
return $res;
}
/* 返回前一次操作改动的行数 */
function affected_rows() {
return @mysql_affected_rows($this->Link_ID);
}
/* 返回符合查询结果的行数 */
function num_rows() {
return @mysql_num_rows($this->Query_ID);
}
/* 返回查询结果的列的数目 */
function num_fields() {
return @mysql_num_fields($this->Query_ID);
}
/* 返回查询结果中Name字段的值 */
function f($Name) {
return $this->Record[$Name];
}
/* 打印查询结果中Name字段的值 */
function p($Name) {
print $this->Record[$Name];
}
/* 以数组的形式返回查询结果 */
function fetch_array() {
return $this->Record;
}
/* 数据库的信息，原封未动 */
function metadata($table='',$full=false) {
$count = 0;
$id = 0;
$res = array();
/*
* Due to compatibility problems with Table we changed the behavior
* of metadata();
* depending on $full, metadata returns the following values:
*
* - full is false (default):
* $result[]:
* [0]["table"] table name
* [0]["name"] field name
* [0]["type"] field type
* [0]["len"] field length
* [0]["flags"] field flags
*
* - full is true
* $result[]:
* ["num_fields"] number of metadata records
* [0]["table"] table name
* [0]["name"] field name
* [0]["type"] field type
* [0]["len"] field length
* [0]["flags"] field flags
* ["meta"][field name] index of field named "field name"
* The last one is used, if you have a field name, but no index.
* Test: if (isset($result['meta']['myfield'])) { ...
*/
// if no $table specified, assume that we are working with a query
// result
if ($table) {
$this->connect();
$id = @mysql_list_fields($this->Database, $table);
if (!$id)
$this->halt("Metadata query failed.");
} else {
$id = $this->Query_ID;
if (!$id)
$this->halt("No query specified.");
}
$count = @mysql_num_fields($id);
// made this IF due to performance (one if is faster than $count if's)
if (!$full) {
for ($i=0; $i<$count; $i++) {
$res[$i]["table"] = @mysql_field_table ($id, $i);
$res[$i]["name"] = @mysql_field_name ($id, $i);
$res[$i]["type"] = @mysql_field_type ($id, $i);
$res[$i]["len"] = @mysql_field_len ($id, $i);
$res[$i]["flags"] = @mysql_field_flags ($id, $i);
}
} else { // full
$res["num_fields"]= $count;
for ($i=0; $i<$count; $i++) {
$res[$i]["table"] = @mysql_field_table ($id, $i);
$res[$i]["name"] = @mysql_field_name ($id, $i);
$res[$i]["type"] = @mysql_field_type ($id, $i);
$res[$i]["len"] = @mysql_field_len ($id, $i);
$res[$i]["flags"] = @mysql_field_flags ($id, $i);
$res["meta"][$res[$i]["name"]] = $i;
}
}
// free the result only if we were called on a table
if ($table) @mysql_free_result($id);
return $res;
}
/*-------------------------------------*
* 返回数据库中所有的表格名称，说明： *
* 将返回一个数组，其中包括了所有的表 *
* 格，每个表格是数组的一个元素，每个 *
* 元素又是一个数组，包括了teble_name *
* 和database两个元素，table_name是表 *
* 格的名称，database是数据库的名称。 *
*-------------------------------------*/
function table_names() {
$this->query("SHOW TABLES");
$i=0;
while ($info=mysql_fetch_row($this->Query_ID)) {
$return[$i]["table_name"]= $info[0];
$return[$i]["database"]=$this->Database;
$i++;
}
return $return;
}
/* 错误信息处理函数，下面都是 */
function halt($msg) {
$this->Error = @mysql_error($this->Link_ID);
$this->Errno = @mysql_errno($this->Link_ID);
if ($this->Halt_On_Error == "no")
return;
$this->haltmsg($msg);
if ($this->Halt_On_Error != "report")
die("Session halted.");
}
function haltmsg($msg) {
printf("</td></tr></table><b>Database error:</b> %s<br>\n", $msg);
printf("<b>MySQL Error</b>: %s (%s)<br>\n",
$this->Errno,
$this->Error);
}
/* 栏目增加和减少项目的函数 */
function counts($seq_name, $mode = '+') {
$this->connect();
if ($this->lock($this->Seq_Table)) {
$q = sprintf("select num from %s where seq_name = '%s'", $this->Seq_Table, $seq_name);
$id = @mysql_query($q, $this->Link_ID);
$res = @mysql_fetch_array($id);
//如果没有这个row，建立一个
if (!is_array($res)) {
$currentid = 0;
$q = sprintf("insert into %s values('%s', %s)", $this->Seq_Table, $seq_name, $currentid);
$id = @mysql_query($q, $this->Link_ID);
}
if($mode=='+') {
$this->id_add($seq_name);
$count = $res[0]+1;
} else {
$this->id_minus($seq_name);
$count = $res[0]-1;
}
$this->unlock();
} else {
$this->halt("Cannot lock ".$this->Seq_Table." - has it been created?");
return false;
}
return $count;
}
function id_add($seq_name) {
$q = sprintf("update %s set num = num+1 where seq_name = '%s'", $this->Seq_Table, $seq_name);
$current = @mysql_query($q, $this->Link_ID);
return $current;
}
function id_minus($seq_name) {
$q = sprintf("update %s set num = num-1 where seq_name = '%s'", $this->Seq_Table, $seq_name);
$current = @mysql_query($q, $this->Link_ID);
return $current;
}
// Class DB_SQL Ended
}
/*----------------------------------------------------------------------------
id_minus id_add和nextid的用法：
必须建立一个表格，表格名称为Seq_Table的值
其中seq_name代表项目名称，num代表数目
----------------------------------------------------------------------------*/
?>
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