Free PHP Programing Scripts

Sunday, August 17, 2008

PHP Database ODBC

Create an ODBC Connection

With an ODBC connection, you can connect to any database, on any computer in your network, as long as an ODBC connection is available.

Here is how to create an ODBC connection to a MS Access Database:

Open the Administrative Tools icon in your Control Panel.
Double-click on the Data Sources (ODBC) icon inside.
Choose the System DSN tab.
Click on Add in the System DSN tab.
Select the Microsoft Access Driver. Click Finish.
In the next screen, click Select to locate the database.
Give the database a Data Source Name (DSN).
Click OK.

Note that this configuration has to be done on the computer where your web site is located. If you are running Internet Information Server (IIS) on your own computer, the instructions above will work, but if your web site is located on a remote server, you have to have physical access to that server, or ask your web host to to set up a DSN for you to use.

Connecting to an ODBC

The odbc_connect() function is used to connect to an ODBC data source. The function takes four parameters: the data source name, username, password, and an optional cursor type.

The odbc_exec() function is used to execute an SQL statement.

Example

The following example creates a connection to a DSN called northwind, with no username and no password. It then creates an SQL and executes it:

$conn=odbc_connect('northwind','','');
$sql="SELECT * FROM customers"; 
$rs=odbc_exec($conn,$sql);

Retrieving Records

The odbc_fetch_row() function is used to return records from the result-set. This function returns true if it is able to return rows, otherwise false.

The function takes two parameters: the ODBC result identifier and an optional row number:

odbc_fetch_row($rs)

Retrieving Fields from a Record

The odbc_result() function is used to read fields from a record. This function takes two parameters: the ODBC result identifier and a field number or name.

The code line below returns the value of the first field from the record:

$compname=odbc_result($rs,1);

The code line below returns the value of a field called "CompanyName":

$compname=odbc_result($rs,"CompanyName");

Closing an ODBC Connection

The odbc_close() function is used to close an ODBC connection.

odbc_close($conn);

An ODBC Example

The following example shows how to first create a database connection, then a result-set, and then display the data in an HTML table.

<html>
<body>

<?php
$conn=odbc_connect('northwind','','');
if (!$conn)
  {exit("Connection Failed: " . $conn);}
$sql="SELECT * FROM customers";
$rs=odbc_exec($conn,$sql);
if (!$rs)
  {exit("Error in SQL");}
echo "<table><tr>";
echo "<th>Companyname</th>";
echo "<th>Contactname</th></tr>";
while (odbc_fetch_row($rs))
{
  $compname=odbc_result($rs,"CompanyName");
  $conname=odbc_result($rs,"ContactName");
  echo "<tr><td>$compname</td>";
  echo "<td>$conname</td></tr>";
}
odbc_close($conn);
echo "</table>";
?>

</body>
</html>

PHP MySQL Delete From

Delete Data In a Database

The DELETE FROM statement is used to delete records from a database table.

Syntax

DELETE FROM table_name
WHERE column_name = some_value

Note: SQL statements are not case sensitive. DELETE FROM is the same as delete from.

To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

Earlier in the tutorial we created a table named "Person". Here is how it looks:

FirstName	LastName	Age
Peter	Griffin	35
Glenn	Quagmire	33

The following example deletes all the records in the "Person" table where LastName='Griffin':

<?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='Griffin'");

mysql_close($con);
?>

After the deletion, the table will look like this:

FirstName	LastName	Age
Glenn	Quagmire	33

PHP MySQL Update

Update Data In a Database

The UPDATE statement is used to modify data in a database table.

Syntax

UPDATE table_name
SET column_name = new_value
WHERE column_name = some_value

Note: SQL statements are not case sensitive. UPDATE is the same as update.

To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

Earlier in the tutorial we created a table named "Person". Here is how it looks:

FirstName

LastName

Age

Peter

Griffin

35

Glenn

Quagmire

33

The following example updates some data in the "Person" table:

<?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 = '36'
WHERE FirstName = 'Peter' AND LastName = 'Griffin'");

mysql_close($con);
?>

After the update, the "Person" table will look like this:

FirstName	LastName	Age
Peter	Griffin	36
Glenn	Quagmire	33

PHP MySQL Order By Keyword

The ORDER BY Keyword

The ORDER BY keyword is used to sort the data in a recordset.

Syntax

SELECT column_name(s)
FROM table_name
ORDER BY column_name

Note: SQL statements are not case sensitive. ORDER BY is the same as order by.

Example

The following example selects all the data stored in the "Person" table, and sorts the result by the "Age" column:

<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("my_db", $con);

$result = mysql_query("SELECT * FROM person ORDER BY age");

while($row = mysql_fetch_array($result))
  {
  echo $row['FirstName'];
  echo " " . $row['LastName'];
  echo " " . $row['Age'];
  echo "<br />";
  }

mysql_close($con);
?>

The output of the code above will be:

Glenn Quagmire 33
Peter Griffin 35

Sort Ascending or Descending

If you use the ORDER BY keyword, the sort-order of the recordset is ascending by default (1 before 9 and "a" before "p").

Use the DESC keyword to specify a descending sort-order (9 before 1 and "p" before "a"):

SELECT column_name(s)
FROM table_name
ORDER BY column_name DESC

Order by Two Columns

It is possible to order by more than one column. When ordering by more than one column, the second column is only used if the values in the first column are identical:

SELECT column_name(s)
FROM table_name
ORDER BY column_name1, column_name2

PHP MySQL The Where Clause

The WHERE clause

To select only data that matches a specific criteria, add a WHERE clause to the SELECT statement.

Syntax

SELECT column FROM table
WHERE column operator value

The following operators can be used with the WHERE clause:

Operator

Description

=

Equal

!=

Not equal

>

Greater than

<

Less than

>=

Greater than or equal

<=

Less than or equal

BETWEEN

Between an inclusive range

LIKE

Search for a pattern

Note: SQL statements are not case sensitive. WHERE is the same as where.

To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

The following example will select all rows from the "Person" table, where FirstName='Peter':

<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("my_db", $con);

$result = mysql_query("SELECT * FROM person
WHERE FirstName='Peter'");

while($row = mysql_fetch_array($result))
  {
  echo $row['FirstName'] . " " . $row['LastName'];
  echo "<br />";
  }

?>

The output of the code above will be:

Peter Griffin

PHP MySQL Select

Select Data From a Database Table

The SELECT statement is used to select data from a database.

Syntax

SELECT column_name(s)
FROM table_name

Note: SQL statements are not case sensitive. SELECT is the same as select.

To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

The following example selects all the data stored in the "Person" table (The * character selects all of the data in the table):

<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("my_db", $con);

$result = mysql_query("SELECT * FROM person");

while($row = mysql_fetch_array($result))
  {
  echo $row['FirstName'] . " " . $row['LastName'];
  echo "<br />";
  }

mysql_close($con);
?>

The example above stores the data returned by the mysql_query() function in the $result variable. Next, we use the mysql_fetch_array() function to return the first row from the recordset as an array. Each subsequent call to mysql_fetch_array() returns the next row in the recordset. The while loop loops through all the records in the recordset. To print the value of each row, we use the PHP $row variable ($row['FirstName'] and $row['LastName']).

The output of the code above will be:

Peter Griffin
Glenn Quagmire

Display the Result in an HTML Table

The following example selects the same data as the example above, but will display the data in an HTML table:

<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("my_db", $con);

$result = mysql_query("SELECT * FROM person");

echo "<table border='1'>
<tr>
<th>Firstname</th>
<th>Lastname</th>
</tr>";

while($row = mysql_fetch_array($result))
  {
  echo "<tr>";
  echo "<td>" . $row['FirstName'] . "</td>";
  echo "<td>" . $row['LastName'] . "</td>";
  echo "</tr>";
  }
echo "</table>";

mysql_close($con);
?>

The output of the code above will be:

Firstname	Lastname
Glenn	Quagmire
Peter	Griffin

PHP MySQL Insert Into

Insert Data Into a Database Table

The INSERT INTO statement is used to add new records to a database table.

Syntax

INSERT INTO table_name
VALUES (value1, value2,....)

You can also specify the columns where you want to insert the data:

INSERT INTO table_name (column1, column2,...)
VALUES (value1, value2,....)

Note: SQL statements are not case sensitive. INSERT INTO is the same as insert into.

To get PHP to execute the statements above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

In the previous chapter we created a table named "Person", with three columns; "Firstname", "Lastname" and "Age". We will use the same table in this example. The following example adds two new records to the "Person" table:

<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("my_db", $con);

mysql_query("INSERT INTO person (FirstName, LastName, Age) 
VALUES ('Peter', 'Griffin', '35')");

mysql_query("INSERT INTO person (FirstName, LastName, Age) 
VALUES ('Glenn', 'Quagmire', '33')");

mysql_close($con);
?>

Insert Data From a Form Into a Database

Now we will create an HTML form that can be used to add new records to the "Person" table.

Here is the HTML form:

<html>
<body>

<form action="insert.php" method="post">
Firstname: <input type="text" name="firstname" />
Lastname: <input type="text" name="lastname" />
Age: <input type="text" name="age" />
<input type="submit" />
</form>

</body>
</html>

When a user clicks the submit button in the HTML form in the example above, the form data is sent to "insert.php". The "insert.php" file connects to a database, and retrieves the values from the form with the PHP $_POST variables. Then, the mysql_query() function executes the INSERT INTO statement, and a new record will be added to the database table.

Below is the code in the "insert.php" page:

<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("my_db", $con);

$sql="INSERT INTO person (FirstName, LastName, Age)
VALUES
('$_POST[firstname]','$_POST[lastname]','$_POST[age]')";

if (!mysql_query($sql,$con))
  {
  die('Error: ' . mysql_error());
  }
echo "1 record added";

mysql_close($con)
?>