ACCESSING A DATABASE USING PHP
Use the following variables:-
$host - address of the host having the MySQL database.
$database - name of the database at the host.
$username - the user of the database.
$password - the password to access the database.
The variables and their values should be in a file at a secure location on the server.
dbinfo.php - example of a name of a file used to hold the database variables and
their data.
Include the filename of the database variables once as an include file at the
top of the program. For example:-
include("dbinfo.php");
In the database program try and access the database using an Exception procedure
with the following variables:-
$db - results of database access.
$e - error message if there is an exception.
Note the inverted commas in the example below enclose mysql and dbname and their values.
try{
$db = new PDO("mysql:host=$host; dbname=$database", $username, $password);
}
catch(PDOException $e){
echo "Error connecting to database ".$database."!",$e->getMessage();
exit();
}
After successfully accessing the database a copy of the database should be in the
variable $db.
Use the following variables to select the information required from a table in the
database:-
$tablename - name of table
$row - name of array to hold data required obtained from a row in the database.
The following code can be used to list the contents of the database to the screen.
foreach($db->query("SELECT * FROM $tablename") as $row){
echo ("Subject: ".$row["subject"]." Answer: ".$row["message"]);
}
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