一个简单的数据库连接和文本缓存综合类

没什么特色，就是把数据库连接和文本缓存封装在一个类里面了

1. class Db{
2. protected $_connect;
3. protected $_db = Array();
4. protected $_cache = Array();
6. public function __construct($args){
7. list($this->_db,$this->_cache) = $args;
8. }
9. protected function connect($db){
10. $this->_connect = mysql_connect($db['hostname'],$db['username'],$db['password']);
11. mysql_set_charset('UTF8');
12. mysql_select_db($db['databasename'],$this->_connect);
13. }
14. /**
15. *作用：获取表中数据，并将所查询到的数据格式化返回，返回格式是数组形式！
16. *$sql：传入的待执行的SQL语句，必须而且只能是SELECT
17. *
18. */
19. public function fetch($sql){
20. $result = '';
21. if(isset($this->_cache['expire'])){
22. $name = md5(strtolower(str_replace(' ','',$sql)));
23. $dir = substr($name,0,2);
24. $dir = $this->_cache['dir'].'/'.$dir;
25. !is_dir($dir) && mkdir($dir,0777);
26. !is_dir($dir) && mkdir($dir,0777);
27. $this->_cache['path'] = $dir.'/'.$name;
28. if(is_file($this->_cache['path']) && $this->check_expire()){
29. $result = $this->get();
30. }
31. }
32. if($result == ''){
33. $data = $this->exec($sql);
34. $result = Array();
35. while($result[] = mysql_fetch_array($data,MYSQL_ASSOC)){} //去除索引
36. mysql_free_result($data);
37. array_pop($result);
38. isset($this->_cache['expire']) && $this->write($result);
39. }
40. return $result;
41. }
42. /**
43. *作用：执行所有的SQL语句，但不包括SELECT！
44. *$sql：传入的待执行的SQL语句，不能为SELECT
45. *返回值：TRUE OR FALSE
46. */
47. public function exec($sql){
48. if($this->_connect === null) $this->connect($this->_db); //进行数据链接
49. if( $result = mysql_query($sql, $this->_connect) ){
50. return $result;
51. }else{
52. die("{$sql}
    执行错误: " . mysql_error());
53. }
54. }
55. /**
56. *作用：执行数据库插入语句，只能是INSERT语句！
57. *$v：传入的待执行的条件，是数组格式table代表待执行插入的表，row是字段，value是待插入的值
58. *返回值：mysql_insert_id() OR FALSE
59. */
60. public function insert($table,$field,$ignore = 0){
61. $D = Array('field'=>'','val'=>'');
62. foreach($field AS $key => $v){
63. $D['field'] .= $key.',';
64. $D['val'] .= "'{$this->escape($v)}',";
65. }
66. $D['field'] = rtrim($D['field'],',');
67. $D['val'] = rtrim($D['val'],',');
68. $ignore = $ignore > 0 ? 'IGNORE' : '';
69. $sql = "INSERT {$ignore} INTO {$this->_db['perfix']}{$table}({$D['field']}) VALUES({$D['val']})";
70. if($this->exec($sql)){
71. $insert_id = mysql_insert_id();
72. return is_numeric($insert_id) ? $insert_id : TRUE;
73. }else{
74. return FALSE;
75. }
76. }
77. public function update($table,$field){
78. $D = Array('where'=>'','str'=>'');
79. $index = 0;
80. foreach($field AS $key => $v){
81. $index == 0 ? $D['where'] = "{$key} = '{$this->escape($v)}'" : $D['str'] .= "{$key} = '{$this->escape($v)}',";
82. $index++;
83. }
84. $D['str'] = rtrim($D['str'],',');
85. $sql = "UPDATE {$this->_db['perfix']}{$table} SET {$D['str']} WHERE {$D['where']}";
86. return $this->exec($sql);
88. }
89. public function delete($table,$field){
90. $str = '';
91. foreach($field AS $key => $v){
92. $str = "{$key} = '{$v}'";
93. }
94. $sql = 'DELETE FROM '.$this->_db['perfix'].$table.' WHERE '.$str.' LIMIT 1';
95. return $this->exec($sql);
96. }
97. public function sum($table,$condition){
98. $totle = $this->fetch('SELECT COUNT(*) AS totle FROM '.$this->_db['perfix'].$table.' WHERE '.$condition);
99. return $totle[0]['totle'];
100. }
101. /**
102. *作用：对输入特殊字符进行过滤
103. *$v：待传入检测的参数
104. *返回值：检测完的参数
105. */
106. public function escape($v){
107. return mysql_real_escape_string($v);
108. }
109. /*
110. *作用：进行缓存判断
111. */
112. public function cache($name,$expire=100000000){
113. $this->_cache['expire'] = $expire;
114. return $this;
115. }
116. public function check_expire(){
117. return (filemtime($this->_cache['path']) + $this->_cache['expire']) > strtotime("now");
118. }
120. public function write($data){
121. $f = fopen($this->_cache['path'], 'w');
122. if ($f) {
123. flock($f, LOCK_EX);
124. fseek($f, 0);
125. ftruncate($f, 0);
126. $tmp = fwrite($f, serialize($data));
127. if (!($tmp === false)) {
128. $result = true;
129. }
130. fclose($f);
131. }
132. chmod($this->_cache['path'],0777);
133. }
134. public function get(){
135. $f = fopen($this->_cache['path'], 'r');
136. $data = fread($f,filesize($this->_cache['path']));
137. fclose($f);
138. return unserialize($data);
139. }
140. public function delete_dir($dir = ''){
141. $dir = empty($dir) ? $this->_cache['dir'] : $dir;
142. !is_dir($dir) && exit;
143. $d = opendir($dir);
144. $i = 0;
145. while(($file = readdir($d)) !== false){
146. $path = $dir.'/'.$file;
147. if($i > 1) is_file($path) ? unlink($path) : $this->delete_dir($path);
148. $i++;
149. }
150. closedir($d);
151. rmdir($dir);
152. }
153. public function __destruct(){
154. isset($this->_connect) && mysql_close($this->_connect);
155. }
156. }

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