重新封装的PHPLib DB类（推荐简单项目使用本类库）

封装|项目

为了便于自己的开发，但是又不想使用ADODB、PEAR::DB这样的庞然大物，就在PHPLib DB类的基础上、参考PEAR::DB类，封装了自己的DB类，简单好使，非常方便。目前只针对MySQL有效，没什么技术含量，姑且为参考。

使用本类库只是需要把下面代码保存为database.inc.php或者database.class.php，在自己需要的地方include进来，然后实例化对象，然后调用连接方法，最后在执行操作。

[ 连接数据库 ]

//包含数据库处理类文件
include_once("database.inc.php");

//本地数据库配置
define("DB_HOST", "localhost"); //数据库服务器
define("DB_USER_NAME", "root"); //数据库用户名
define("DB_USER_PASS", ""); //密码
define("DB_DATABASE", "test"); //数据库

//连接本地数据库
$db = new DB_Sql();
$db->connect(DB_DATABASE, DB_HOST, DB_USER_NAME, DB_USER_PASS);

[ 使用方法 ]

//获取所有记录
$sql = "SELECT * FROM table1";
$all_record = $db->get_all($sql);

//获取一条
$sql = "SELECT * FROM table1 WHERE id = '1'";
$one_row = $db->get_one($sql);

//分页查询，提取20条记录
$sql = "SELECT * FROM table1";
$page_record = $db->limit_query($sql, $start=0, $offset=20, $order="ORDER BY id DESC");

//提取指定数目的记录
$sql = "SELECT * FROM table1";
$limit_record = $db->get_limit($sql);

//统计记录数，统计所有类型为学生的
$count = $db->count("table1", "id", "type = 'student'");

//插入一条记录
$info_array = array(
"name" => "heiyeluren",
"type" => "student",
"age" => "22",
"gender" => "boy"
);
$db->insert("table1", $info_array);

//更新一条记录
$info_array = array(
"name" => "heiyeluren",
"type" => "teacher",
"age" => "22",
"gender" => "boy"
);
$db->update("table1", $info_array, "name = 'heiyeluren'");

//删除记录
$db->delete("table1", "name = 'heiyeluren'");

//执行一条无结果集的SQL
$db->execute("DELETE FROM table1 WHERE name = 'heiyeluren'");

[ 类库代码 ]

/**
* 文件: database.inc.php
* 描述: 数据库操作类
* 作者: heiyeluren
* 创建: 2005-12-25
* 修改: 2005-12-26
* 说明: 本库使用PHPLib DB库作为核心, 同时增加一些实用方法, 详细参考注释
*/

class DB_Sql
{

/* public: connection parameters */
var $Host = "";
var $Database = "";
var $User = "";
var $Password = "";

/* public: configuration parameters */
var $Auto_Free = 1; ## Set to 1 for automatic mysql_free_result()
var $Debug = 0; ## Set to 1 for debugging messages.
var $Halt_On_Error = "yes"; ## "yes" (halt with message), "no" (ignore errors quietly), "report" (ignore errror, but spit a warning)
var $PConnect = 0; ## Set to 1 to use persistent database connections
var $Seq_Table = "db_sequence";

/* public: result array and current row number */
var $Record = array();
var $Row;

/* public: current error number and error text */
var $Errno = 0;
var $Error = "";

/* public: this is an api revision, not a CVS revision. */
var $type = "mysql";
//var $revision = "1.2";

/* private: link and query handles */
var $Link_ID = 0;
var $Query_ID = 0;

var $locked = false; ## set to true while we have a lock

/* public: constructor */
function DB_Sql() {
$this->query($query);
}

/* public: some trivial reporting */
function link_id() {
return $this->Link_ID;
}

function query_id() {
return $this->Query_ID;
}

/* public: connection management */
function connect($Database = "", $Host = "", $User = "", $Password = "") {
/* Handle defaults */
if ("" == $Database)
$Database = $this->Database;

if ("" == $Host)
$Host = $this->Host;

if ("" == $User)
$User = $this->User;

if ("" == $Password)
$Password = $this->Password;

/* establish connection, select database */
if ( 0 == $this->Link_ID ) {

if(!$this->PConnect) {
$this->Link_ID = mysql_connect($Host, $User, $Password);
} else {
$this->Link_ID = mysql_pconnect($Host, $User, $Password);
}
if (!$this->Link_ID) {
$this->halt("connect($Host, $User, \$Password) failed.");
return 0;
}

if (!@mysql_select_db($Database,$this->Link_ID)) {
$this->halt("cannot use database ".$Database);
return 0;
}
}

return $this->Link_ID;
}

/* public: discard the query result */
function free() {
@mysql_free_result($this->Query_ID);
$this->Query_ID = 0;
}

/* public: perform a query */
function query($Query_String) {
/* No empty queries, please, since PHP4 chokes on them. */
if ($Query_String == "")
/* The empty query string is passed on from the constructor,
* when calling the class without a query, e.g. in situations
* like these: '$db = new DB_Sql_Subclass;'
*/
return 0;

if (!$this->connect()) {
return 0; /* we already complained in connect() about that. */
};

# New query, discard previous result.
if ($this->Query_ID) {
$this->free();
}

if ($this->Debug)
printf("Debug: query = %s
\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);
}

# Will return nada if it fails. That's fine.
return $this->Query_ID;
}

/* public: walk result set */
function next_record() {
if (!$this->Query_ID) {
$this->halt("next_record called with no query pending.");
return 0;
}

$this->Record = @mysql_fetch_array($this->Query_ID);
$this->Row += 1;
$this->Errno = mysql_errno();
$this->Error = mysql_error();

$stat = is_array($this->Record);
if (!$stat && $this->Auto_Free) {
$this->free();
}
return $stat;
}

/* public: position in result set */
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.");

/* half assed attempt to save the day,
* but do not consider this documented or even
* desireable behaviour.
*/
@mysql_data_seek($this->Query_ID, $this->num_rows());
$this->Row = $this->num_rows();
return 0;
}

return 1;
}

/* public: table locking */
function lock($table, $mode = "write") {
$query = "lock tables ";
if(is_array($table)) {
while(list($key,$value) = each($table)) {
// text keys are "read", "read local", "write", "low priority write"
if(is_int($key)) $key = $mode;
if(strpos($value, ",")) {
$query .= str_replace(",", " $key, ", $value) . " $key, ";
} else {
$query .= "$value $key, ";
}
}
$query = substr($query, 0, -2);
} elseif(strpos($table, ",")) {
$query .= str_replace(",", " $mode, ", $table) . " $mode";
} else {
$query .= "$table $mode";
}
if(!$this->query($query)) {
$this->halt("lock() failed.");
return false;
}
$this->locked = true;
return true;
}

function unlock() {

// set before unlock to avoid potential loop
$this->locked = false;

if(!$this->query("unlock tables")) {
$this->halt("unlock() failed.");
return false;
}
return true;
}

/* public: evaluate the result (size, width) */
function affected_rows() {
return @mysql_affected_rows($this->Link_ID);
}

function num_rows() {
return @mysql_num_rows($this->Query_ID);
}

function num_fields() {
return @mysql_num_fields($this->Query_ID);
}

/* public: shorthand notation */
function nf() {
return $this->num_rows();
}

function np() {
print $this->num_rows();
}

function f($Name) {
if (isset($this->Record[$Name])) {
return $this->Record[$Name];
}
}

function p($Name) {
if (isset($this->Record[$Name])) {
print $this->Record[$Name];
}
}

/* public: sequence numbers */
function nextid($seq_name) {
/* if no current lock, lock sequence table */
if(!$this->locked) {
if($this->lock($this->Seq_Table)) {
$locked = true;
} else {
$this->halt("cannot lock ".$this->Seq_Table." - has it been created?");
return 0;
}
}

/* get sequence number and increment */
$q = sprintf("select nextid from %s where seq_name = '%s'",
$this->Seq_Table,
$seq_name);
if(!$this->query($q)) {
$this->halt('query failed in nextid: '.$q);
return 0;
}

/* No current value, make one */
if(!$this->next_record()) {
$currentid = 0;
$q = sprintf("insert into %s values('%s', %s)",
$this->Seq_Table,
$seq_name,
$currentid);
if(!$this->query($q)) {
$this->halt('query failed in nextid: '.$q);
return 0;
}
} else {
$currentid = $this->f("nextid");
}
$nextid = $currentid + 1;
$q = sprintf("update %s set nextid = '%s' where seq_name = '%s'",
$this->Seq_Table,
$nextid,
$seq_name);
if(!$this->query($q)) {
$this->halt('query failed in nextid: '.$q);
return 0;
}

/* if nextid() locked the sequence table, unlock it */
if($locked) {
$this->unlock();
}

return $nextid;
}

/* public: return table metadata */
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
* $result[]:
* ["num_fields"] number of metadata records
* [0]["table"] table name
* [0]["name"] field name
* [0]["type"] field type
* [0]["len"] field length
* [0]["flags"] field flags
* ["meta"][field name] index of field named "field name"
* This last one could be used if you have a field name, but no index.
* Test: if (isset($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.");
return false;
}
} else {
$id = $this->Query_ID;
if (!$id) {
$this->halt("No query specified.");
return false;
}
}

$count = @mysql_num_fields($id);

// made this IF due to performance (one if is faster than $count if's)
if (!$full) {
for ($i=0; $i $res[$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 $res[$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;
}

/* public: find available table names */
function table_names() {
$this->connect();
$h = @mysql_query("show tables", $this->Link_ID);
$i = 0;
while ($info = @mysql_fetch_row($h)) {
$return[$i]["table_name"] = $info[0];
$return[$i]["tablespace_name"] = $this->Database;
$return[$i]["database"] = $this->Database;
$i++;
}

@mysql_free_result($h);
return $return;
}

/* private: error handling */
function halt($msg) {
$this->Error = @mysql_error($this->Link_ID);
$this->Errno = @mysql_errno($this->Link_ID);

if ($this->locked) {
$this->unlock();
}

if ($this->Halt_On_Error == "no")
return;

$this->haltmsg($msg);

if ($this->Halt_On_Error != "report")
die("Session halted.");
}

function haltmsg($msg) {
printf("Database error: %s
\n", $msg);
printf("MySQL Error: %s (%s)
\n",
$this->Errno,
$this->Error);
}

//----------------------------------
// 模块: 自定义函数
// 功能: 部分实用的数据库处理方法
// 作者: heiyeluren
// 时间: 2005-12-26
//----------------------------------

/**
* 方法: execute($sql)
* 功能: 执行一条SQL语句，主要针对没有结果集返回的SQL
* 参数: $sql 需要执行的SQL语句，例如：execute("DELETE FROM table1 WHERE id = '1'")
* 返回: 更新成功返回True，失败返回False
*/
function execute($sql)
{
if (empty($sql))
{
$this->error("Invalid parameter");
}
if (!$this->query($sql))
{
return false;
}
return true;
}

/**
* 方法: get_all($sql)
* 功能: 获取SQL执行的所有记录
* 参数: $sql 需要执行的SQL,例如: get_all("SELECT * FROM Table1")
* 返回: 返回包含所有查询结果的二维数组
*/
function get_all($sql)
{
$this->query($sql);
$result_array = array();
while($this->next_record())
{

$result_array[] = $this->Record;
}
if (count($result_array) {
return 0;
}
return $result_array;
}

/**
* 方法: get_one($sql)
* 功能: 获取SQL执行的一条记录
* 参数: $sql 需要执行的SQL,例如: get_one("SELECT * FROM Table1 WHERE id = '1'")
* 返回: 返回包含一条查询结果的一维数组
*/
function get_one($sql)
{
$this->query($sql);
if (!$this->next_record())
{
return 0;
}
return $this->Record;
}

/**
* 方法: get_limit($sql, $limit)
* 功能: 获取SQL执行的指定数量的记录
* 参数:
* $sql 需要执行的SQL,例如: SELECT * FROM Table1
* $limit 需要限制的记录数
* 例如 需要获取10条记录, get_limit("SELECT * FROM Table1", 10);
*
* 返回: 返回包含所有查询结果的二维数组
*/
function get_limit($sql, $limit)
{
$this->query($sql);
$result_array = array();
for ($i=0; $inext_record(); $i++)
{
$result_array[] = $this->Record;
}
if (count($result_array) {
return 0;
}
return $result_array;
}

/**
* 方法: limit_query($sql, $start=0, $offset=20, $order="")
* 功能: 为分页的获取SQL执行的指定数量的记录
* 参数:
* $sql 需要执行的SQL,例如: SELECT * FROM Table1
* $start 记录的开始数, 缺省为0
* $offset 记录的偏移量，缺省为20
* $order 排序方式，缺省为空，例如：ORDER BY id DESC
* 例如 需要获取从0到10的记录并且按照ID号倒排, get_limit("SELECT * FROM Table1", 0, 10, "ORDER BY id DESC");
*
* 返回: 返回包含所有查询结果的二维数组
*/
function limit_query($sql, $start=0, $offset=20, $order="")
{
$sql = $sql ." $order LIMIT $start,$offset";
$this->query($sql);
$result = array();
while($this->next_record())
{
$result[] = $this->Record;
}
if (count($result) {
return 0;
}
return $result;
}

/**
* 方法: count($table,$field="*", $where="")
* 功能: 统计表中数据总数
* 参数:
* $table 需要统计的表名
* $field 需要统计的字段，默认为*
* $where 条件语句，缺省为空
* 例如 按照ID统计所有年龄小于20岁的用户, count("user_table", "id", "user_age *
* 返回: 返回统计结果的数字
*/
function count($table,$field="*", $where="")
{
$sql = (empty($where) ? "SELECT COUNT($field) FROM $table" : "SELECT COUNT($field) FROM $table WHERE $where");
$result = $this->get_one($sql);
if (!is_array($result))
{
return 0;
}
return $result[0];
}

/**
* 方法: insert($table,$dataArray)
* 功能: 插入一条记录到表里
* 参数:
* $table 需要插入的表名
* $dataArray 需要插入字段和值的数组，键为字段名，值为字段值，例如：array("user_name"=>"张三", "user_age"=>"20岁");
* 例如 比如插入用户张三，年龄为20, insert("users", array("user_name"=>"张三", "user_age"=>"20岁"))
*
* 返回: 插入记录成功返回True，失败返回False
*/
function insert($table,$dataArray)
{
if (!is_array($dataArray) || count($dataArray) {
$this->error("Invalid parameter");
}
while(list($key,$val) = each($dataArray))
{
$field .= "$key,";
$value .= "'$val',";
}
$field = substr($field, 0, -1);
$value = substr($value, 0, -1);
$sql = "INSERT INTO $table ($field) VALUES ($value)";
if (!$this->query($sql))
{
return false;
}
return true;
}

/**
* 方法: update($talbe, $dataArray, $where)
* 功能: 更新一条记录
* 参数:
* $table 需要更新的表名
* $dataArray 需要更新字段和值的数组，键为字段名，值为字段值，例如：array("user_name"=>"张三", "user_age"=>"20岁");
* $where 条件语句
* 例如 比如更新姓名为张三的用户为李四，年龄为21
* update("users", array("user_name"=>"张三", "user_age"=>"20岁"), "user_name='张三'")
*
* 返回: 更新成功返回True，失败返回False
*/
function update($talbe, $dataArray, $where)
{
if (!is_array($dataArray) || count($dataArray) {
$this->error("Invalid parameter");
}
while(list($key,$val) = each($dataArray))
{
$value .= "$key = '$val',";
}
$value = substr($value, 0, -1);
$sql = "UPDATE $talbe SET $value WHERE $where";
if (!$this->query($sql))
{
return false;
}
return true;
}

/**
* 方法: delete($table, $where)
* 功能: 删除一条记录
* 参数:
* $table 需要删除记录的表名
* $where 需要删除记录的条件语句
* 例如 比如要删除用户名为张三的用户，delete("users", "user_name='张三'")
*
* 返回: 更新成功返回True，失败返回False
*/
function delete($table, $where)
{
if (empty($where))
{
$this->error("Invalid parameter");
}
$sql = "DELETE FROM $table WHERE $where";
if (!$this->query($sql))
{
return false;
}
return true;
}

/**
* 方法: error($msg="")
* 功能: 显示错误信息后中止脚本
* 参数: $msg 需要显示的错误信息
* 返回: 无返回
*/
function error($msg="")
{
echo "Error: $msg\n
\n";
exit();
}

/**
* 方法：get_insert_id()
* 功能：获取最后插入的ID
* 参数: 无参数
* 返回：关闭成功返回ID，失败返回0
*/
function get_insert_id()
{
return mysql_insert_id($this->Link_ID);
}

/**
* 方法：close()
* 功能：关闭当前数据库连接
* 参数: 无参数
* 返回：关闭成功返回true，失败返回false
*/
function close()
{
return mysql_close($this->Link_ID);
}
}
?>