Three-Tier Development with PHP 5
Smarty files
It's time to create several files for Smarty:
include.php
1 <?
2 require('Smarty.class.php');
3 $smarty = new Smarty;
4 $smarty->template_dir = 'templates/';
5 $smarty->compile_dir = 'templates_c/';
6 $smarty->config_dir = 'configs/';
7 $smarty->cache_dir = 'cache/';
?>
This script instantiates a new Smarty object for the application.
index.php
1 <?
2 require("include.php");
3 $smarty->assign('TITLE','ACCESS MySQL DATABASE IN THREE TIERS WITH PHP');
4 $smarty->assign('HEADER','WHAT WISH DO ?');
5 $smarty->display('index.tpl');
?>
This script shows how to assign values to variables with Smarty. It calls include.php on line 2.
insert.php
1 <?
2 require("include.php");
3 $smarty->assign('TITLE','INSERT DATA');
4 $smarty->assign('HEADER','Insert Data');
5 $smarty->assign('data1','First Name');
6 $smarty->assign('data2','Last Name');
7 $smarty->assign('data3','email');
8 $smarty->display('insert.tpl');
?>
Much like the previous script, this adds variables that will appear in the
insert.tpl template.
save.php
1 <?
2 require_once('DB/DataObject.php');
3 require('configDB.php');
4 $user = DB_DataObject::factory('user');
5 $user->first_Name = $x;
6 $user->last_Name = $y;
7 $user->email = $z;
8 $user_Id = $user->insert();
9 $user->update();
10 echo "<script>location.href='index.php'</script>";
11 ?>
This script saves data by using a PEAR::DataObject for the user
table. Line 2 loads the class DataObject, and line 3 calls configdb.php
to connect to the database. Line 4 creates an instance of a user
object (see User.php).
Lines 5 through 7 pass the variables collected from the form in
insert.tpl ($x, $y, and $z) in
order to save the data in the database. The primary key of the table is an
autoincrement column, so it doesn't need a value there. Line 8 inserts the
object, and line 9 carries out an update.
view.php
1 <?
2 require_once('DB/DataObject.php');
3 require('configDB.php');
4 require("include.php");
5 $user = DB_DataObject::factory('user');
6 $user->find();
7 while ($user->fetch()) {
8 $smarty->append('users', array(
'ID' => $user->user_Id,
'FIRSTNAME' => $user->first_Name,
'LASTNAME' => $user->last_Name,
'EMAIL' => $user->email,
));
}
9 $smarty->assign('TITLE','List Users');
10 $smarty->assign('HEADER','List User');
11 $smarty->assign('data0','User_Id');
12 $smarty->assign('data1','First Name');
13 $smarty->assign('data2','Last Name');
14 $smarty->assign('data3','email');
15 $smarty->display('view.tpl');
16 ?>
This script displays all of the data stored in the user table.
It loads PEAR::DataObject and include.php (to assign variables of
Smarty) that to be shown in the template view.tpl. Line 5 creates a factory of
user objects. Line 6 issues a find, which is
equivalent to SELECT * FROM user. After selecting the data, it's
time to store it for the template via fetch(). This returns one
record at a time, which the code stores in a template variable named
users, append()ing each row, named by the keys
ID, FIRSTNAME, LASTNAME, and
EMAIL.
Lines 9 through 14 assign values to other Smarty variables.
All of these .php files should go in the dataobjects
directory.
Now for the templates, there are index.tpl, list.tpl, and
save.tpl. Here is their code:
index.tpl
1 <html>
2 <head>
3 <title>{$TITLE}</title>
4 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
5 </head>
6 <table align="center">
7 <tr>
8 <td>
9 <b>{$HEADER}</b>
10 </td>
11 </tr>
12 </table>
13 <table width="250" border="1" align="center" >
14 <tr>
16 <td align="center">
17 <input type="button" name="insert" value="Insert"
onclick="javascript:location.href='insert.php';">
18 </td>
19 </tr>
20 <tr>
21 <td align="center">
22 <input type="button" name="view" value="View"
onclick="javascript:location.href='view.php';">
23 </td>
24 </tr>
25 </table>
26 </body>
27 </html>
This template is the main page of the system. It shows two variables,
$TITLE and $HEADER, in lines 3 and 9,
respectively. These values of the variables come from index.php.
Later comes a table with two buttons, Insert and View, which have those
respective actions. If the user clicks on Insert, the server invokes
insert.php (see line 17). If the user clicks on View, this calls
view.php (see lines 3 and 4 of that script).
insert.tpl
1 <html>
2 <head>
3 <title>{$TITLE}</title>
4 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
5 </head>
6 <body>
7 <form name="form1" action="save.php" method="post">
8 <table width="300" border="1" align="center" >
9 <tr>
10 <td align="center">
11 <b>{$HEADER}</b>
12 </td>
13 </tr>
14 <tr>
15 <td>
16 {$data1}
17 <input type="text" name="x">
18 </td>
19 </tr>
20 <tr>
21 <td>
22 {$data2}
23 <input type="text" name="y">
24 </td>
25 </tr>
26 <tr>
27 <td>
28 {$data3}
29 <input type="text" name="z">
30 </td>
31 </tr>
32 <tr>
33 <td align="center">
34 <input type="submit" name="Submit" value="Add">
35 <input type="button" name="Reset" value="Return/Cancel"
onclick="javascript:location.href='index.php';">
36 </td>
37 </tr>
38 </table>
39 </form>
40 </body>
41 </html>
This template has a form and two buttons, Add and Return/Cancel.
The user enters data for the first name, last name, and email fields (lines 16, 22, and
28). insert.php expects to receive this information in variables named
x, y, and z (lines 17, 23, and 29).
Clicking on the Add button calls save.php (see line 7) to perform the
save. In the contrary case, if the user clicks on Return/Cancel, it executes
index.php (line 35).
view.tpl
1 <html>
2 <head>
3 <title>{$TITLE}</title>
4 </head>
5 <body>
6 <table align="center">
7 <tr>
8 <td align="center">
9 <b>{$HEADER}</b>
10 </td>
11 </tr>
12 </table>
13 <table width="500" border="1" align="center">
14 <tr>
16 <td align="center">
17 <b>{$data0}</b>
18 </td>
19 <td align="center">
20 <b>{$data1}</b>
21 </td>
22 <td align="center">
23 <b>{$data2}</b>
24 </td>
25 <td align="center">
26 <b>{$data3}</b>
27 </td>
28 </tr>
29 {section name=display loop=$users}
30 <tr>
31 <td>
32 {$users[display].ID}
33 </td>
34 <td>
35 {$users[display].FIRSTNAME}
36 </td>
37 <td>
38 {$users[display].LASTNAME}
39 </td>
40 <td>
41 {$users[display].EMAIL}
42 </td>
43 </tr>
44 {/section}
45 <br>
46 </table>
47 <br>
48 <table align="center">
49 <tr>
50 <td align="center">
51 <input name="vol" type="button" value="Return"
onclick="javascript:location.href='index.php';">
52 </td>
53 </tr>
54 </table>
55 </body>
56 </html>
This template is able to display all of the data stored in the
database example.
The first table shows the HEADER of the table, and the second shows data with
its respective header (see lines 17, 20, 23, and 26, with the values coming
from view.php). Line 29 shows the extraction of data by looping over
the users array from view.php to show the values of the user, ID, FIRSTNAME,
LASTNAME, and EMAIL fields (lines 32, 35, 38, and 41).
Finally, the Return button sends users back to the home page.
All of the template files (*.tpl) must go in the templates
directory.
Conclusion
Working in three tiers with PHP saves repetitive work and makes for
maintainable code, partly due to object oriented programming. It's easy to use
the powerful Smarty and PEAR::DB_DataObject together.
Luis Yordano Cruz
is a systems engineer in Trujillo PERU with more than five years of experience developing web-based applications with PHP, Java/J2EE, and JavaScript.
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