Chapter 5 | Section 5.2 |
Using JDBC/ODBC Operations | JDBC eWay Database Operations (JCD) |
FileClient_1.write();
}
}
Manipulating the ResultSet and Update Count Returned by Stored Procedure
For Stored Procedures that return ResultSets and Update Count, the following methods are provided to manipulate the ResultSet:
enableResultSetOnly
enableUpdateCountsOnly
enableResultSetandUpdateCounts
resultsAvailable
next
getUpdateCount
available
Many drivers do not support manipulating ResultSets in a Stored Procedure. It is recommended that you use specific eWay Adapters for Oracle, SQL Server, Sybase, DB2, and so forth, to peform such operations.
JDBC stored procedures do not return records as ResultSets. Instead, the records are returned through output reference cursor parameters. Reference Cursor parameters are essentially ResultSets.
The resultsAvailable() method, added to the PreparedStatementAgent class, simplifies the whole process of determining whether any results, be it Update Counts or ResultSets, are available after a stored procedure has been executed. Although JDBC provides three methods (getMoreResults(), getUpdateCount(), and getResultSet()) to access the results of a stored procedure call, the information returned from these methods can be quite confusing to the inexperienced Java JDBC programmer and they also differ between vendors. You can simply call resultsAvailable() and if Boolean true is returned, you can expect either a valid Update Count when getUpdateCount() is called and/or the next ResultSet has been retrieved and made available to one of the ResultSet nodes defined for the Stored Procedure OTD, when that node’s available() method returns true.
Frequently, Update Counts information that is returned from a Stored Procedures is insignificant. You should process returned ResultSet information and avoid looping through all of the Update Counts. The following three methods control exactly what information should be returned from a stored procedure call. The enableResultSetsOnly() method, added to the PreparedStatement Agent class allows only ResultSets to be returned and thus every resultsAvailable() called only returns Boolean true if a ResultSet is available. Likewise, the enableUpdateCountsOnly() causes resultsAvailable() to return true only if an Update Count is available. The default case of enableResultsetsAndUpdateCount() method allows both ResultSets and Update Counts to be returned.
JDBC/ODBC eWay Adapter User’s Guide | 65 | Sun Microsytems, Inc. |
