Showing posts with label mysql_close. Show all posts
Showing posts with label mysql_close. Show all posts

Sunday, 10 July 2011

PHP MySQL :: ODBC Connection

ODBC is an Application Programming Interface (API) that allows you to connect to a data source (e.g. an MS Access database).

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: 
  1. Open the Administrative Tools icon in your Control Panel.
  2. Double-click on the Data Sources (ODBC) icon inside.
  3. Choose the System DSN tab.
  4. Click on Add in the System DSN tab.
  5. Select the Microsoft Access Driver. Click Finish.
  6. In the next screen, click Select to locate the database.
  7. Give the database a Data Source Name (DSN).
  8. 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 :: Select Data From a Database Table

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

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
To learn more about SQL, please visit our SQL tutorial.
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 "Persons" table (The * character selects all 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 Persons");

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 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 Persons");

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:
FirstnameLastname
GlennQuagmire
PeterGriffin

PHP MySQL :: Insert Data Into a Database Table

The INSERT INTO statement is used to insert new records in a table.

Insert Data Into a Database Table

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

Syntax

It is possible to write the INSERT INTO statement in two forms.
The first form doesn't specify the column names where the data will be inserted, only their values:
INSERT INTO table_name
VALUES (value1, value2, value3,...)
The second form specifies both the column names and the values to be inserted:
INSERT INTO table_name (column1, column2, column3,...)
VALUES (value1, value2, value3,...)

To learn more about SQL, please visit our SQL tutorial.
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 "Persons", 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 "Persons" 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 Persons (FirstName, LastName, Age)
VALUES ('Peter', 'Griffin', '35')");

mysql_query("INSERT INTO Persons (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 "Persons" 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 "Persons" table.
Here is 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);

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

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

mysql_close($con)
?>

MySQL :: Connection to Database

The free MySQL database is very often used with PHP.

Create a Connection to a MySQL Database

Before you can access data in a database, you must create a connection to the database.
In PHP, this is done with the mysql_connect() function.

Syntax

mysql_connect(servername,username,password);

ParameterDescription
servernameOptional. Specifies the server to connect to. Default value is "localhost:3306"
usernameOptional. Specifies the username to log in with. Default value is the name of the user that owns the server process
passwordOptional. Specifies the password to log in with. Default is ""
Note: There are more available parameters, but the ones listed above are the most important. Visit our full PHP MySQL Reference for more details.

Example

In the following example we store the connection in a variable ($con) for later use in the script. The "die" part will be executed if the connection fails:
<?php
$con = mysql_connect("localhost",
"root","rootpassword");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

// some code
?>


Closing a Connection

The connection will be closed automatically when the script ends. To close the connection before, use the mysql_close() function:
<?php
$con = mysql_connect("localhost","root","rootpassword");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

// some code

mysql_close($con);
?>