PHP and MySQL
IT Engineering I
Instructor: Ali B. Hashemi
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1
Connect to a MySQL
† Before accessing your database, you
must make a connection to it.
† mysql_connect()
mysql_connect
Syntax
mysql_connect(server, user, password);
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2
Connect to a MySQL
Parameter
server
user
password
Description
Optional. Specifies the server to connect to (can
also include a port number. e.g. "hostname:port" or
a path to a local socket for the localhost). Default
value is "localhost:3306"
Optional. Specifies the username to log in with.
Default value is the name of the user that owns the
server process
Optional. Specifies the password to log in with.
Default is ""
mysql_connect("localhost","root",'1234'))
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Connect to a MySQL
Example
<?php
$con=mysql_connect("localhost",“yourlogin","abc");
if (!$con) {
// The "die" part of the code is an error check.
die('Could not connect: ' . mysql_error());
}
Echo “you are successfully connected with the mysql
server”;
// some code …
//Closing a Connection
mysql_close($con );
?>
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mysql_error()
† mysql_error(): Shows the error
message that has been returned
directly from the MySQL server.
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Connect to a database
<?php
$con=mysql_connect("localhost",“yourlogin","abc123");
if (!$con) {
die('Could not connect: ' . mysql_error());
}
$select = mysql_select_db ("mydb")
//$select = mysql_select_db("my_db", $con);
if(!$select){
die('Could not connect: ' . mysql_error());
}
// remaining code here
?>
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Inserting data
<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con) {
die('Could not connect: ' . mysql_error());
}
$select = mysql_select_db (“test");
if(!$select){
die('Could not connect: ' . mysql_error());
}
$sql="INSERT INTO items VALUES ('testing', 'C','Yellow')";
if ($result = mysql_query ("$sql")) {
echo "Data added\n";
}
else error_report ();
?>
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Inserting Data
From a Form to a Database
<form action="insert_db.php" method="POST">
Enter Item Name:
<input type="text" name="itemname" /><br />
Enter Item Type:
<input type="text" maxlength="1“ name="itemtype" />
<br>
Enter Item Color
<input type="text" name="itemcolor" /><br />
<input type="submit" />
</form>
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Inserting data From Form
<?php
$sql="INSERT INTO
items(itemname,itemtype,itemcolour)
VALUES ('$_POST[itemname]','$_POST[itemtype]',
'$_POST[itemcolor]')";
if (!mysql_query($sql))
{
die('Error: ' . mysql_error());
}
echo "Success!";
?>
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View Data
<?php
$result = mysql_query("SELECT * FROM items");
while($row = mysql_fetch_array($result)) {
echo “Item name:”.$row['itemName'].”<br>";
echo “Item Type:”.$row['itemType'].”<br>";
echo “Item name:”.$row['itemcolour'].”<br>";
echo "<br>";
}
?>
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mysql_fetch_array($results)
† mysql_fetch_array("results
variable from query"):
mysql_fetch_array
Used to return several rows of the entire results of
a database query.
† The mysql_fetch_array function gets the
next line in an array from a MySQL result
† use the (while)
while loop to continue to get the
next array until there is no next array to
get
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Updating Data
<?php
$con=mysql_connect("localhost","peter","abc123");
if (!$con) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db("my_db", $con);
mysql_query("UPDATE Person SET Age = ‘10’ WHERE
LastName = 'Hashemi'");
?>
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Delete Data
<?php
$con=mysql_connect("localhost","peter","abc123");
if (!$con) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db("my_db", $con);
mysql_query(“delete FROM Person WHERE LastName =
‘Hashemi'");
?>
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mysql_affected_rows()
† The mysql_affected_rows() function
„ returns the number of affected rows in the previous
MySQL operation.
changed by the most recent DELETE, INSERT,
REPLACE, or UPDATE statement
† When returning rows, acts the same way as
mysql_num_rows()
†
„ returns the number of affected rows on success, or -1
if the last operation failed.
† Syntax: mysql_affected_rows(connection)
„ Optional.
„ Specifies the MySQL connection.
„ If not specified, the last connection opened by
mysql_connect() or mysql_pconnect() is used.
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mysql_affected_rows()
Example
<?php
$con=mysql_connect("localhost","mysql_user","mysql_pwd");
if (!$con)
{ die("Could not connect: " . mysql_error()); }
mysql_select_db("mydb");
mysql_query("DELETE FROM mytable WHERE id < 5");
$rc = mysql_affected_rows();
echo "Records deleted: " . $rc; mysql_close($con);
?>
†
The output of the code above could be:
Records deleted:7
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mysql_fetch_row()
† mysql_fetch_rows("results variable from query") Used
to return a row of the entire results of a database
query.
† The mysql_fetch_row() function returns
a row from a recordset as a numeric
array.
array
„ Parameter: results of a database query
(could be mysql_query() function
„ returns an array on success, or FALSE on
failure or when there are no more rows.
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mysql_fetch_row()
Example
<?php
$result = mysql_query($sql,$con);
print_r (mysql_fetch_row($result));
mysql_close($con);
?>
Output:
Array (
[0] => Refsnes
[1] => Kai Jim
[2]=> Taugata 2
[3] => 22
)
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mysql_field_name()
† The mysql_field_name()
„ Returns the field name on success, or FALSE on
failure.
† Syntax: mysql_field_name(data,field_offset)
„ data Required.
† Specifies which data pointer to use. The data
pointer is the result from the mysql_query()
function
„ field_offsetRequired.
† Specifies which field to start returning. 0 indicates
the first field
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mysql_field_name()
Example
<?php
$sql = "SELECT * from Person";
$result = mysql_query($sql,$con);
$name = mysql_field_name($result, 0);
echo $name;
mysql_close($con);
?>
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mysql_num_fields()
† The mysql_num_fields()
„ returns the number of fields in a
recordset.
„ returns FALSE on failure.
† Syntax: mysql_num_fields(data)
„ Data Required.
† Specifies which data pointer to use.
† The data pointer is the result from the
mysql_query() function
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mysql_num_fields()
Example
<?php
$sql = "SELECT * FROM person";
$result = mysql_query($sql,$con);
echo mysql_num_fields($result);
mysql_close($con);
?>
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mysql_num_rows()
† The mysql_num_rows()
„ returns the number of rows in a
recordset.
„ returns FALSE on failure.
† Syntax: mysql_num_rows(data)
„ Data Required.
† Specifies which data pointer to use. The
data pointer is the result from the
mysql_query() function
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mysql_num_rows()
Example
<?php
$sql = "SELECT * FROM person";
$result = mysql_query($sql,$con);
echo mysql_num_rows($result);
mysql_close($con);
?>
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