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PHP Tutorials - Selecting an Existing Database

By: FYICenter.com

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How To Select an Exiting Database?

The first thing after you have created a connection object to the MySQL server is to select the database where your tables are locate, by using the mysql_select_db() function. If your MySQL server is offered by your Web hosting company, they will assign a database to you and provide you the database name. You should use this name to select your database as your current database. The following script shows you how to select a database called "fyi". It also shows you how to put all the database connection statements in a single include file, and re-use it in all of your PHP pages.

Create the include file, connect.php, with the following statements:

<?php
  $server = "localhost";
  $username = "";
  $password = "";
  $database = "fyi";
  $con = mysql_connect($server, $username, $password);
  mysql_select_db($database);
?>

To test this database connection and selection include file, try the following script:

<?php
  include "mysql_connection.php";

  $sql = 'SHOW TABLES';
  if ($rs = mysql_query($sql, $con)) {
    print(mysql_num_rows($rs) . " tables in the database.\n");
  } else {
    print("SHOW TABLES failed.\n");
  }

  mysql_close($con); 
?>

You will get something like this:

0 tables in the database.

(Continued on next topic...)

1. How To Install MySQL Server?
2. How To Use MySQL Command Line Interface?
3. What Do You Need to Connect PHP to MySQL?
4. How To Connect to MySQL from a PHP Script?
5. How To Create a Database?
6. How To Select an Exiting Database?
7. How To Run a SQL Statement?
8. How To Create a Table?
9. How To Get the Number of Rows Selected or Affected by a SQL Statement?
10. How To Insert Data into a Table?
11. How To Insert Rows Based on SELECT Statements?
12. What Is a Result Set Object?
13. How To Query Tables and Loop through the Returning Rows?
14. How To Update Existing Rows in a Table?
15. How To Delete Existing Rows in a Table?
16. How To Quote Text Values in SQL Statements?
17. How To Quote Date and Time Values in SQL Statements?
18. How To Perform Key Word Search in Tables?
19. How To Query Multiple Tables Jointly?
20. How To Set the ID Column as Auto-Incremented?
21. How To Get the Last ID Assigned by MySQL?