A connection context represents a connection to a particular database schema. So far, all the SQLJ programs you have seen have used one database connection, established using a call to the Oracle.connect( ) method. For example, the program FundamentalExample1.sqlj described in Chapter 3 used the following call to connect to the fundamental_user schema:
Oracle.connect( "jdbc:oracle:thin:@localhost:1521:orcl", "fundamental_user", "fundamental_password" );
A call to the Oracle.connect( ) method creates an object of the sqlj.runtime.ref.DefaultContext class, which may then be used to access the database. This DefaultContext object is known as the default connection context, and it is the database connection that the rest of the program uses by default when performing SQL operations. You can create additional connection contexts in order to make multiple database connections.
Sometimes, a single database connection may not be enough for your program to accomplish its task. For example, you might need to connect to two or more schemas in the database at the same time to retrieve the data you need. It is possible to create multiple database connections by explicitly creating additional objects of the DefaultContext class.
The oracle.sqlj.runtime.Oracle class contains a method named getConnection( ) that creates and returns a DefaultContext object, which may then be stored in a DefaultContext object that you explicitly ...