JDBC

Objects instantiated by classes that implement the DataSource represent a particular DBMS or some other data source, such as a file. A DataSource object represents a particular DBMS or some other data source, such as a file. If a company uses more than one data source, it will deploy a separate DataSource object for each of them. The DataSource interface is implemented by a driver vendor. It can be implemented in three different ways:

• A basic DataSource implementation produces standard Connection objects that are not pooled or used in a distributed transaction.
• A DataSource implementation that supports connection pooling produces Connection objects that participate in connection pooling, that is, connections that can be recycled.
• A DataSource implementation that supports distributed transactions produces Connection objects that can be used in a distributed transaction, that is, a transaction that accesses two or more DBMS servers.

A JDBC driver should include at least a basic DataSource implementation. For example, the Java DB JDBC driver includes the implementation org.apache.derby.jdbc.ClientDataSource and for MySQL, com.mysql.jdbc.jdbc2.optional.MysqlDataSource.