Kid Code Script

Opening a connection to MySQL database from PHP is easy. Just use the mysql_connect() function like this

$dbhost is the name of MySQL server. When your webserver is on the same machine with the MySQL server you can use localhost or 127.0.0.1 as the value of $dbhost. The $dbuser and $dbpass are valid MySQL user name and password.

Don't forget to select a database using mysql_select_db() after connecting to mysql. If no database selected your query to select or update a table will not work.

Closing the Connection

The connection opened in a script will be closed as soon as the execution of the script ends. But it's better if you close it explicitly by calling mysql_close() function. You could also put this function call in a file named closedb.php.

Now that you have put the database configuration, opening and closing routines in separate files your PHP script that uses mysql would look something like this :

• 
  
  ' Visual Basic
  Public Sub ConnectToOracle()
     Dim conn As New OracleClient.OracleConnection()
     ' TODO: Modify the connection string and include any
     ' additional required properties for your database.
     conn.ConnectionString = & _
     "Data Source=;Integrated Security=yes"
     Try
         conn.Open()
         ' Insert code to process data.
     Catch ex As Exception
         MessageBox.Show("Failed to connect to data source")
     Finally
         conn.Close()
     End Try
  End Sub
  
  // C#
  public void ConnectToOracle()
  {
     OracleClient.OracleConnection conn =
         new OracleClient.OracleConnection ();
     // TODO: Modify the connection string and include any
     // additional required properties for your database.
     conn.ConnectionString = "Data Source=" +
         ";Integrated Security=yes";
     try
     {
         conn.Open();
         // Insert code to process data.
     }
         catch (Exception ex)
     {
         MessageBox.Show("Failed to connect to data source");
     }
     finally
     {
         conn.Close();
     }
  }

• 
  
  ' Visual Basic
     Public Sub ConnectToOdbc()
         Dim conn As New System.Data.Odbc.OdbcConnection
         ' TODO: Modify the connection string and include any
         ' additional required properties for your database.
         conn.ConnectionString = & _
             "FIL=MS Access;DSN=valid data source name"
         Try
             conn.Open()
             ' Insert code to process data.
         Catch ex As Exception
             MessageBox.Show("Failed to connect to data source")
         Finally
             conn.Close()
         End Try
     End Sub
  
  // C#
  public void ConnectToData()
  {
     System.Data.Odbc.OdbcConnection conn =
         new System.Data.Odbc.OdbcConnection ();
     // TODO: Modify the connection string and include any
     // additional required properties for your database.
     conn.ConnectionString = "FIL=MS Access;DSN=valid data source name";
     try
     {
         conn.Open();
         // Process data here.
     }
     catch (Exception ex)
     {
         MessageBox.Show("Failed to connect to data source");
     }
     finally
     {
         conn.Close();
     }
  }

• 
  
  ' Visual Basic
  Public Sub ConnectToAccess()
     Dim conn As New System.Data.OleDb.OleDbConnection()
     ' TODO: Modify the connection string and include any
     ' additional required properties for your database.
     conn.ConnectionString = & _
     "Provider=Microsoft.Jet.OLEDB.4.0;Data source=" & _
     "C:\Documents and Settings\username\My Documents\dbFile.mdb"
     Try
        conn.Open()
        ' Insert code to process data.
     Catch ex As Exception
        MessageBox.Show("Failed to connect to data source")
     Finally
        conn.Close()
     End Try
  End Sub
  
  // C#
  public void ConnectToAccess()
  {
     System.Data.OleDb.OleDbConnection conn = new
         System.Data.OleDb.OleDbConnection();
     // TODO: Modify the connection string and include any
     // additional required properties for your database.
     conn.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;" +
         @"Data source= C:\Documents and Settings\username\" +
         @"My Documents\AccessFile.mdb";
     try
     {
         conn.Open();
         // Insert code to process data.
     }
         catch (Exception ex)
     {
         MessageBox.Show("Failed to connect to data source");
     }
     finally
     {
         conn.Close();
     }
  }

• 
  
  ' Visual Basic
  Public Sub ConnectToSql()
     Dim conn As New SqlClient.SqlConnection
     ' TODO: Modify the connection string and include any
     ' additional required properties for your database.
     conn.ConnectionString = & _
     "integrated security=SSPI;data source=SQL Server Name;" & _
     "persist security info=False;initial catalog=northwind"
     Try
         conn.Open()
         ' Insert code to process data.
     Catch ex As Exception
         MessageBox.Show("Failed to connect to data source")
     Finally
         conn.Close()
     End Try
  End Sub
  
  // C#
  public void ConnectToSql ()
  {
     System.Data.SqlClient.SqlConnection conn =
         new System.Data.SqlClient.SqlConnection ();
     // TODO: Modify the connection string and include any
     // additional required properties for your database.
     conn.ConnectionString =
      "integrated security=SSPI;data source=SQL Server Name;" +
      "persist security info=False;initial catalog=northwind";
     try
     {
         conn.Open();
         // Insert code to process data.
     }
         catch (Exception ex)
     {
         MessageBox.Show("Failed to connect to data source");
     }
     finally
     {
         conn.Close();
     }
  }