Delphi for .NET Developer’s Guide

Opening and Closing Connections

To open a connection to the data store, you simply invoke the SqlConnection.Open() method. Likewise, to close the connection, invoke the SqlConnection.Close() method.

Note

If connection pooling is supported, opening a connection will try to use a connection from the pool; otherwise, a new connection is established to the data store. Also, closing a pooled connection adds the connection to the pool instead of actually closing it. Connection pooling is discussed later in this chapter.

Listing 18.1 illustrates the opening and closing of a SQL Server connection.

Listing 18.1. Opening and Closing a Connection

1: program test; 2: {$APPTYPE CONSOLE} 3: uses 4: System.Data.SQLClient; 5: const 6: CNSTR = 'server=localhost;database=Northwind;Trusted_Connection=Yes'; ...