Setting Up a Simple Database with PHP
- Putting Content into Your Database with PHP
- Getting Content Out of Your Database with PHP
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PHP and MySQL go together like peanut butter and jelly. PHP was designed to work easily with MySQL, and the designers did an excellent job!
This article gives you a brief introduction into getting some data into and out of a database using PHP. First you'll need to find a MySQL server that you can connect to. You can download a free version of MySQL from http://www.mysql.com. The instructions for setting up a MySQL server are on that site as well.
Before you even start your PHP coding, you need to create a database in MySQL to store your data. Make certain that you have your MySQL daemon running. In the instructions that follow, replace DBNAME with whatever name you want to name your database. If you are using Windows, you need to execute any MySQL commands from C:\mysql\bin. For Linux, you can issue the commands from any shell prompt. To create your database, issue the following command:
prompt>mysqladmin create DBNAME
To set up the tables in your new database, you need to log into your MySQL server. This is done by using the MySQL command-line interface.
At the prompt, issue the following command (assuming that you are using the default setup—otherwise, use your normal login):
prompt> mysql –u root
This command logs you into the server. From here, you can create tables, delete (drop) tables, and modify the data in your tables. But first, you must specify which database on the server you want to use because the MySQL server is capable of hosting multiple databases.
At the MySQL prompt, enter the following command. Be sure to replace DBNAME with your database's name.
mysql> use DBNAME;
The MySQL server responds with:
Database changed
You've now selected your database. Any of the basic SQL queries that you enter are directed to this database.
Now you can create the table you'll be using for the upcoming projects. Enter the following commands at the MySQL prompt. Hit Return after each line. MySQL doesn't try to interpret the command until it sees a semicolon (;), so the command itself isn't really "executed" on the server until you enter the last line.
If the server gives you a big ERROR and spits out a bunch of garbage at you, just try again from the TOP. You need to enter each line in the sequence from the beginning exactly as shown.
mysql> CREATE TABLE news ( -> news_id INT NOT NULL AUTO_INCREMENT, -> heading VARCHAR(48), -> body TEXT, -> date DATE, -> author_name VARCHAR(48), -> author_email VARCHAR(48), -> PRIMARY KEY(news_id));
NOTE
The -> prompt that you see after entering a line in the MySQL server is telling you that it's waiting for more input before it does anything.
The server responds with:
Query OK, 0 rows affected (0.00 sec)
Congratulations! You've just created your first table in MySQL.
Putting Content into Your Database with PHP
Now that you have had a little experience using SQL queries from the MySQL command line, lets try some queries using PHP. Using PHP for the task is less cumbersome and more flexible. Above all, it can easily be done using a Web browser.
The logic behind PHP and database interaction is simple:
Connect to the database server and log in.
Choose the database to use.
Send SQL queries to the server to add, delete, and modify data.
You don't even have to worry about closing the connection to the server because PHP does it for you.
data_in.php
This next script in Listing 1 shows you just how easy it is to put data into a database. What PHP allows you to do in a few short, simple lines is amazing. This script uses the "news" MySQL table that you created earlier. If you haven't done so, you need to create it now. Out of the 30 lines of code in the script, there are only about 10 that are PHP-specific. The rest is plain HTML.
Listing 1: data_in.php
1. <html>
2. <head>
3. <title>Putting Data in the Database</title>
4. </head>
5. <body bgcolor="#FFFFFF">
6. <?php
7. /* This program enters news items into a database */
8. if(isset($submit)):
9. $db = mysql_connect("localhost", "root");
10. mysql_select_db("php3", $db);
11. $date = date("Y-m-d");
12. $sql = "INSERT INTO news
13. VALUES(NULL,'$heading','$body','$date', '$auth','$auth_email')";
14. mysql_query($sql);
15. print("<h2>The Data Has Been Entered</h2>\n");
16. print("<b>You can add another news story below</b><hr>\n");
17. endif;
18. ?>
19. <p><h3>Enter your news item into the database</h3>
20. <form action="data_in.php" method="post">
21. Name:<br><input type="text" name="auth"><p>
22. Email:<br> <input type="text" name="auth_email"><p>
23. Heading:<br><input type="text" name="heading"><p>
24. News:<br>
25. <textarea cols=40 rows=20 name="body" wrap="virtual">
26. </textarea><p>
27. <input type="submit" name="submit" value="Submit News!">
28. </form>
29. </body>
30. </html>
How the Script Works
Here's what each line in Listing 1 does:
|
8 |
The script checks to see if the Submit button has been pressed. If it has, it executes the code. If not, it skips to the endif part of the script. In this script, if the button isn't pressed, the PHP code is almost completely ignored. This makes for faster initial loading of the page. |
|
9 |
A variable is assigned to the mysql_connect function. This variable is used in the next line to actually establish the connection. The arguments for the function tell the script to connect to the MySQL server running on localhost and to log into it with a username of root. This particular server doesn't require a password, so it has not been included as an argument to the function. |
|
10 |
The script calls the function mysql_select_db, which selects the database that you want to use, and it also initiates the connection to the server by calling the value of the $db variable. |
|
12 |
This is the SQL statement. In this case, the statement is assigned to a variable so that the mysql_query is easier to read. |
|
14 |
The mysql_query function sends the SQL statement to the MySQL server. The SQL statement that is being sent tells the MySQL server to enter the values that it received from the form into the database table. Here the script also prints out a message letting the user know that the data was entered. |
|
19 |
Back to plain old HTML. The beauty of this script is that there isn't a lot of overhead. It has PHP do the hard stuff and lets HTML do the rest. We could have created a function to print the form to the browser, but that would just put more work on the server because it would have to process more PHP directives. With this script, we keep things simple, fast, and efficient. |
The script also repeats itself so that multiple news items can be entered in one session. The HTML form gets printed out every time the script is run; every time the user hits Submit, more data is entered into the database.
Now, of course, this is an ultra-simple example. You may want to include the some error-checking statements, and you would also want to spice it up a little and make it nicer on the eyes for your users using a simple style sheet.