Refer this
http://www.developer.com/net/net/print.php/11087_3530396_2
Example
DbProviderFactory Factory = DbProviderFactories.GetFactory("DDTek.Oracle");DbConnection Conn1 = Factory.CreateConnection();
Conn1.ConnectionString ="Host=Accounting;Port=1521;User ID=scott;Password=tiger; " + "Service Name=ORCL;Min Pool Size=50";
Conn1.Open();// Pool A is created and filled with connections to the //
minimum pool size
DbConnection Conn2 = Factory.CreateConnection();
Conn2.ConnectionString = "Host=Accounting;Port=1521;User ID=Jack;Password=quake; " + "Service Name=ORCL;Min Pool Size=100";
Conn2.Open();// Pool B is created because the connections strings differDbConnection Conn3 = Factory.CreateConnection();
Conn3.ConnectionString = "Host=Accounting;Port=1521;User ID=scott;Password=tiger; " + "Service Name=ORCL;Min Pool Size=50";Conn3.Open();//
Conn3 is assigned an existing connection that was created in // Pool A when the pool was created for Conn1
