Explication détaillée des exemples d'opérations de base de données PHP+sqlite

<?php
define("LN", __LINE__);//行号
define("FL", __FILE__);//当前文件
define("DEBUG", 0);//调试开关
$db_name = "upload.db";
//创建数据库文件,文件内容为空
if (!file_exists($db_name)) {
 if (!($fp = fopen($db_name, "w+"))) {
 exit(error_code(-1, LN));
 }
 fclose($fp);
}
//打开数据库文件
if (!($db = sqlite_open($db_name))) {
 exit(error_code(-2, LN));
}
//产生数据表结构
if (!sqlite_query($db, "DROP TABLE uploads")) {
 exit(error_code(-3, LN));
}
if (!sqlite_query($db, "CREATE TABLE uploads (id integer primary key, file_name varchar(200) UNIQUE, make_time integer)")) {
 exit(error_code(-3, LN));
}
//插入一条数据
if (!sqlite_query($db, " INSERT INTO uploads (file_name, make_time) VALUES (&#39;upload/111.data&#39;,&#39;".time()."&#39;) ")) {
 exit(error_code(-4, LN));
}
//把数据检索出来
if (!($result = sqlite_query($db, "SELECT * FROM uploads"))) {
 exit(error_code(-5, LN));
}
//获取检索数据并显示
while ($array = sqlite_fetch_array($result)) {
 echo "ID: ". $array[file_name] ."<br>: ". $array[make_time] ;
}
/* 错误信息代码函数 */
function error_code($code, $line_num, $debug=DEBUG)
{
 if ($code<-6 || $code>-1) {
 return false;
 }
 switch($code) {
 case -1: $errmsg = "Create database file error.";
  break;
 case -2: $errmsg = "Open sqlite database file failed.";
  break;
 case -3: $errmsg = "Create table failed, table already exist.";
  break;
 case -4: $errmsg = "Insert data failed.";
  break;
 case -5: $errmsg = "Query database data failed.";
  break;
 case -6: $errmsg = "Fetch data failed.";
  break;
 case -7: $errmsg = "";
  break;
 default: $errmsg = "Unknown error.";
 }
 $m = "<b>[ Error ]</b><br>File: ". basename(FL) ." <br>Line: ". LN ."<br>Mesg: ". $errmsg ."";
 if (!$debug) {
 ($m = $errmsg);
 }
 return $m;
}
?>