InfoCenter Home > 4.2.4.2.2: Accessing data with the JDBC 2.0 Core APIWebSphere applications can access a relational database directly through a JDBC provider that uses the JDBC 2.0 Core API. You access a relational database in this manner as follows:
Only a single connection is obtained. This connection does not belong to a pool of connections and is not managed by IBM WebSphere Application Server. It is the responsibility of the application to manage the use of this connection. The following code fragment shows a simple example of obtaining and using a connection directly through a JDBC provider: try { // establish a connection through the DriverManager Class.forName("COM.ibm.db2.jdbc.app.DB2Driver"); String url = "jdbc:db2:sample"; String username = "dbuser"; String password = "passwd"; java.sql.Connection conn = java.sql.DriverManager.getConnection(url, username, password); // query the database java.sql.Statement stmt = conn.createStatement(); java.sql.ResultSet rs = stmt.executeQuery("SELECT EMPNO, FIRSTNME, LASTNAME FROM SAMPLE"); // process the results while (rs.next()) { String empno = rs.getString("EMPNO"); String firstnme = rs.getString("FIRSTNME"); String lastname = rs.getString("LASTNAME"); // work with results } } catch (java.sql.SQLException sqle) { // handle the SQLException } finally { try { if(rs != null) rs.close(); } catch (SQLException sqle) { // can ignore } try { if(stmt != null) stmt.close(); } catch (SQLException sqle) { // can ignore } try { if(conn != null) conn.close(); } catch (SQLException sqle) { // can ignore } } In the previous example, the first action is to establish a connection to the database. This is done by loading and registering the JDBC provider and then requesting a connection from DriverManager. DriverManager, a JDBC 1.0 class, is the basic service for managing a set of JDBC providers. It is necessary to load the driver class before the call to getConnection(), because DriverManager can establish a connection only to a driver that has registered with it. Loading the driver class also registers it with DriverManager. After a connection has been obtained, the database is queried by creating a statement and executing a query on that statement. The query results are put into a ResultSet object. Lastly, the results are processed by stepping through the result set and pulling the data from each record retrieved. According to the JDBC 2.0 Core API specification, the DriverManager class has been deprecated. Therefore, any application using this class should be rewritten to use WebSphere connection pooling, which uses the datasource method described in the JDBC 2.0 Optional Package API to obtain connections to the database. For more information, see the JDBC 2.0 Core API specification. |
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