Controlling JDBC Behavior

JDBC is the underlying database connection protocol. You can control these JDBC features:

• Maximum open cursors

• Fetch mode

• Tracing JDBC calls

You can specify or override the value of these properties on the Java command line or in the Java VM Parameters field of a project's Project | Properties dialog. Use the following syntax:

-D<variable>=<value>

For example, the following command sets the maximum number of open cursors to 10:

-Djbo.max.cursors=10

Maximum Open Cursors

jbo.max.cursors controls the maximum number of open cursors allowed for the database instance. The default value is 50, which is the Oracle database default.

Fetch Mode

jbo.fetch.mode controls the fetch mode for View Objects. Allowed values are:

Value	Description
as.needed	Fetch rows as needed. In other words, JDBC ResultSet and Statement are kept open and rows are retrieved as requested. (Default)
all	Fetch all rows and close the ResultSet and Statement.

When View Objects are linked master-detail and there are many master rows, set jbo.fetch.mode to all to get the best performance. Otherwise, you might run out of memory or cursors as detail rowsets are kept open.

JDBC Calls

jbo.jdbc.trace controls tracing of Business Component calls to JDBC. Allowed values are:

Value	Description
false	Suppress JDBC tracing information. (Default)
true	Output JDBC tracing information.

When this tracing is turned on (true), JDeveloper generates diagnostic messages like these:

[###] import java.util.*;  // JBO-JDBC-INTERACT
[###] import java.sql.*;  // JBO-JDBC-INTERACT
[###] import java.io.*;  // JBO-JDBC-INTERACT
[###] public class JDBCCalls  // JBO-JDBC-INTERACT
[###] {  // JBO-JDBC-INTERACT
[###]    public Connection conn = null;  // JBO-JDBC-INTERACT
[###]    public CallableStatement cStmt = null;  // JBO-JDBC-INTERACT
[###]    public PreparedStatement pStmt = null;  // JBO-JDBC-INTERACT
[###]    public Statement stmt = null;  // JBO-JDBC-INTERACT
[###]    public ResultSet rslt = null;  // JBO-JDBC-INTERACT
[###]    public static void main(String argv[])  // JBO-JDBC-INTERACT
[###]    {  // JBO-JDBC-INTERACT