Smarty程序应用范例：留言簿（Guestbook）第三节

/web/www.example.com/smarty/guestbook/libs/sql.lib.php

<?php

/**
* Project: Guestbook Sample Smarty Application
* Author: Monte Ohrt <monte [AT] ohrt [DOT] com>
* Date: March 14th, 2005
* File: sql.lib.php
* Version: 1.0
*/

// define the query types
define('SQL_NONE', 1);
define('SQL_ALL', 2);
define('SQL_INIT', 3);

// define the query formats
define('SQL_ASSOC', 1);
define('SQL_INDEX', 2);

class SQL {
    
    var $db = null;
    var $result = null;
    var $error = null;
    var $record = null;
    
    /**
     * class constructor
     */
    function SQL() { }
    
    /**
     * connect to the database
     *
     * @param string $dsn the data source name
     */
    function connect($dsn) {
        $this->db = DB::connect($dsn);

        if(DB::isError($this->db)) {
            $this->error = $this->db->getMessage();
            return false;
        }        
        return true;
    }
    
    /**
     * disconnect from the database
     */
    function disconnect() {
        $this->db->disconnect();   
    }
    
    /**
     * query the database
     *
     * @param string $query the SQL query
     * @param string $type the type of query
     * @param string $format the query format
     */
    function query($query, $type = SQL_NONE, $format = SQL_INDEX) {

        $this->record = array();
        $_data = array();
        
        // determine fetch mode (index or associative)
        $_fetchmode = ($format == SQL_ASSOC) ? DB_FETCHMODE_ASSOC
        : null;
        
        $this->result = $this->db->query($query);
        if (DB::isError($this->result)) {
            $this->error = $this->result->getMessage();
            return false;
        }
        switch ($type) {
            case SQL_ALL:
                // get all the records
                while($_row = $this->result->fetchRow($_fetchmode)) {
                    $_data[] = $_row;   
                }
                $this->result->free();            
                $this->record = $_data;
                break;
            case SQL_INIT:
                // get the first record
                $this->record = $this->result->fetchRow($_fetchmode);
                break;
            case SQL_NONE:
            default:
                // records will be looped over with next()
                break;   
        }
        return true;
    }
    
    /**
     * connect to the database
     *
     * @param string $format the query format
     */
    function next($format = SQL_INDEX) {
        // fetch mode (index or associative)
        $_fetchmode = ($format == SQL_ASSOC) ? DB_FETCHMODE_ASSOC 
        : null;
        if ($this->record = $this->result->fetchRow($_fetchmode)) {
            return true;
        } else {
            $this->result->free();
            return false;
        }
            
    }
    
}

?>

接下来是相关参数的速成示例（crash course）：

$guestbook->sql->query("select * from GUESTBOOK", SQL_ALL);
print_r($guestbook->sql->record);

输出结果：
Array
(
[0] => Array
(
[0] => 1
[1] => Monte
[2] => 2005-03-12 17:23:32
[3] => test entry 1
)

[1] => Array
(
[0] => 2
[1] => Monte
[2] => 2005-03-12 17:23:33
[3] => test entry 2
)

[2] => Array
(
[0] => 3
[1] => Monte
[2] => 2005-03-12 17:23:35
[3] => test entry 3
)

)

整个留言簿的内容都显示出来了。“SQL_ALL”会得到所有的查询记录。

$guestbook->sql->query("select * from GUESTBOOK");
while($guestbook->sql->next()) {
print_r($guestbook->sql->record);
}

输出结果:
Array
(
[0] => 1
[1] => Monte
[2] => 2005-03-12 17:23:32
[3] => test entry 1
)

Array
(
[0] => 2
[1] => Monte
[2] => 2005-03-12 17:23:33
[3] => test entry 2
)

Array
(
[0] => 3
[1] => Monte
[2] => 2005-03-12 17:23:35
[3] => test entry 3
)

使用循环的方式一个一个地显示所有记录。如果没有设置query()的第二个参数，那么得到的数据库记录结果会被next()从头到尾遍历。

$guestbook->sql->query("select * from GUESTBOOK", SQL_INIT);
print_r($guestbook->sql->record);

输出结果：
Array
(
[0] => 1
[1] => Monte
[2] => 2005-03-12 17:23:32
[3] => test entry 1
)

输出结果仅仅是一条数据库记录（第一条记录）。 “SQL_INIT”只得到一条记录。

$guestbook->sql->query("select * from GUESTBOOK", SQL_INIT, SQL_ASSOC);
print_r($guestbook->sql->record);

输出结果：
Array
(
[id] => 1
[Name] => Monte
[EntryDate] => 2005-03-12 17:23:32
[Comment] => test entry 1
)

把“SQL_ASSOC”作为第三参数传递给query()会使返回的结果是一个联合数组，形如：fieldname => value。

$guestbook->sql->query("select * from GUESTBOOK");
while($guestbook->sql->next(SQL_ASSOC)) {
print_r($guestbook->sql->record);
}

输出结果：
Array
(
[id] => 1
[Name] => Monte
[EntryDate] => 2005-03-12 17:23:32
[Comment] => test entry 1
)

Array
(
[id] => 2
[Name] => Monte
[EntryDate] => 2005-03-12 17:23:33
[Comment] => test entry 2
)

Array
(
[id] => 3
[Name] => Monte
[EntryDate] => 2005-03-12 17:23:35
[Comment] => test entry 3
)

把“SQL_ASSOC”作为参数传递给next()也会使返回的结果是一个联合数组。

出处：蓝色理想
责任编辑：moby

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