MY SQL-A STARTING

what is my sql ,how connect database in my sql,php database

mysql 

MySQL is currently the most popular open source database server in existence. On top of that, it is very commonly used in conjunction with PHP scripts to create powerful and dynamic server-side applications.

MySQL has been criticized in the past for not supporting all the features of other popular and more expensive DataBase Management Systems. However, MySQL continues to improve with each release (currently version 5), and it has become widely popular with individuals and businesses of many different sizes.

what is a database?

A database is a structure that comes in two flavors: a flat database and a relational database. A relational database is much more oriented to the human mind and is often preferred over the gabble-de-gook flat database that are just stored on hard drives like a text file. MySQL is a relational database.

In a relational structured database there are tables that store data. The columns define which kinds of information will be stored in the table. An individual column must be created for each type of data you wish to store (i.e. Age, Weight, Height).

On the other hand, a row contains the actual values for these specified columns. Each row will have 1 value for each and every column. For example a table with columns (Name, Age, Weight-lbs) could have a row with the values (Bob, 65, 165). If all this relational database talk is too confusing, don't despair. We will talk about and show a few examples in the coming lessons.

creating your first database

Most web hosts do not allow you to create a database directly through a PHP script. Instead they require that you use the PHP/MySQL administration tools on the web host control panel to create these databases. Create a database and assign a new user to this database. For all of our beginning examples we will be using the following information:

• Server - localhost
• Database - test
• Table - example
• Username - admin
• Password - 1admin

Note: The table may change in the advanced lessons, but everything else will remain the same!

The server is the name of the server we want to connect to. Because all of our scripts are going to be placed on the server where MySQL is located the correct address is localhost. If the MySQL server was on a different machine from where the script was running, then you would need to enter the correct url (ask your web host for specifics on this).

mysql connect

Before you can do anything with MySQL in PHP you must first establish a connection to your web host's MySQL database. This is done with the MySQL connect function.

 

mysql localhost

 

If you've been around the internet a while, you'll know that IP addresses are used as identifiers for computers and web servers. In this example of a connection script, we assume that the MySQL service is running on the same machine as the script.

When the PHP script and MySQL are on the same machine, you can uselocalhost as the address you wish to connect to. localhost is a shortcut to just have the machine connect to itself. If your MySQL service is running at a separate location you will need to insert the IP address or URL in place of localhost. Please contact your web host for more details if localhost does not work.

PHP & MySQL Code:

mysql_connect("localhost", "admin", "1admin") or die(mysql_error());

echo "Connected to MySQL
";

?>

If you load the above PHP script to your webserver and everything works properly, then you should see "Connected to MySQL" displayed when you view the .php page.

The mysql_connect function takes three arguments. Server, username, and password. In our example above these arguments were:

• Server - localhost
• Username - admin
• Password - 1admin

The "or die(mysql..." code displays an error message in your browser if --you've probably guessed it -- there is an error in processing the connection! Double-check your username, password, or server if you receive this error.

choosing the working database

 

After establishing a MySQL connection with the code above, you then need to choose which database you will be using with this connection. This is done with the mysql_select_db function.

PHP & MySQL Code:

mysql_connect("localhost", "admin", "1admin") or die(mysql_error());

echo "Connected to MySQL
";

mysql_select_db("test") or die(mysql_error());

echo "Connected to Database";

?>