Each of the connections in the connection pool are defined in the exact same way as a normal ADOdb connection, which makes it simple to add the functionality of existing code. This is shown below:
| Existing ADOdb Connection | Load Balance |
|---|---|
| Instantiate Load Balancer as $db | |
| Instantiate ADOdb as $db | Instantiate ADOdb as $db0, designating the connection as the primary (read-write) connection |
| Connect $db to database using normal connection parameters | Connect $db0 to database using normal connection parameters |
| Add connection $db0 to connection pool $db | |
| Instantiate ADOdb as $db1, designating the connection as a secondary (read-only) connection | |
| Add Connection $db1 to connection pool $db | |
| Repeat for available number of secondary servers | |
| Execute commands against connection $db | Execute commands against connection pool $db |
We show that here, first by creating a normal connection, using a MySQL database
$db = newAdoConnection('mysqli'); $db->connect('host','user','pass','database'); $db->execute('select * from employees');
If we create a load balanced connection, but only assign one server, the method is exactly the same
$db = new ADOdbLoadBalancer; $db0 = new ADOdbLoadBalancerConnection('write',1,'host','user','pass','database'); $db->addConnection($db0); $db->execute('select * from employees')
Note that because we have not assigned any readonly nodes, the write node assumes the responsibility