Transcript PHP Database connectivity

PHP Database connectivity
Connecting with RDBMS and editing, adding,
and deleting databases therein are all done
through PHP functions
 Connect with MySQL RDBMS
–

mysql_connect($hostName, $userName,
$password) or die("Unable to connect to host
$hostName");
Connect with database
–
mysql_select_db($dbName, $con_var) or
die("Unable to select database $dbName");
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Connection Check Code
$link = mysql_connect("localhost", “root", "");
if (!$link) {
echo "Can't connect to localhost. The error
is<br>";
}

Note the use of ! to express Boolean "not".
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PHP Data Base
Queries: Nearly all table interaction and management
is done through queries:
 Mysql_query($query, $con) issues SQL statements
 Basic information searches
–

$SQL = "SELECT FirstName, LastName, DOB, Gender
FROM Patients WHERE Gender = '$Gender‘;
$Patients = mysql_query($SQL,$link) or die (“can execute
query”);
Editing, adding, and deleting records and tables
–
$SQL = "INSERT INTO Patients (FirstName, LastName)
VALUES('$firstName', '$lastName')";
$Patients = mysql_query($SQL);
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PHP Database

Cleaning up: close the database connection,
It requires the connection as an argument, so
that it knows which connection to close.
–
mysql_close($link);
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examining resulting rows

mysql_fetch_array(result) returns an array that is
the result row, or NULL if it the last result is
reached.
–
Its results in an array that contains the columns
requested both by number and by column name:
while($columns=mysql_fetch_array($result)) {
echo 'name: '.$columns['name'];
echo 'first column: ‘.$columns[0];
}
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mysql_num_rows()

This command has the syntax
mysql_select_db($result)
–


where the resource result is the result of a query.
It returns the number of rows that are in the
result.
This is useful in announcing the number
results before display of results.
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Conf.php (Code Example)


<php?
// configuration parameters

// database configuration
$host = “localhost";
$user = “root";
$pass = “";
$db = “db_it";

?>




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Example Code
include("conf.php");
$connection = mysql_connect($host, $user, $pass) or die ("Unable to
connect!");
mysql_select_db($db , $connection) or die ("Unable to select
database!");
$query = "INSERT INTO papers (title, authors, description, comment, super,
bibtex, url, genre) VALUES ('$title', '$authors', '$description', '$comment',
'$super','$bibtex','$url','$genre')";
$result = mysql_query($query , $connection) or die ("Error in query:
$query. " . mysql_error());
// close database connection
mysql_close($connection);
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Example Code
include("conf.php");
$connection = mysql_connect($host, $user, $pass) or die ("Unable to
connect!");
mysql_select_db($db,$connection) or die ("Unable to select database!");
$query = "INSERT INTO papers (title, authors, description, comment,
super, bibtex, url, genre) VALUES ('$title', '$authors', '$description',
'$comment', '$super','$bibtex','$url','$genre')";
$result = mysql_query($query , $connection) or die ("Error in query:
$query. " . mysql_error());
// close database connection
mysql_close($connection);
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Example Code
include("conf.php");
$connection = mysql_connect($host, $user, $pass) or die ("Unable to
connect!");
// select database
mysql_select_db($db,$connection ) or die ("Unable to select
database!");
// generate and execute query
$query = "DELETE FROM papers WHERE id = '$id'";
$result = mysql_query($query) or die ("Error in query: $query. " .
mysql_error());
// close database connection
mysql_close($connection);
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