jdbc: Support Statement.getMoreResults #182
Description
If there are multiple results or if the type or number of results returned by a Statement object are not known until run time, the Statement object should be executed with the method execute. The methods getMoreResults, getUpdateCount, and getResultSet can be used to retrieve all the results.
By default, each call to the method getMoreResults closes any previous ResultSet object returned by the method getResultSet. However, the method getMoreResults may take a parameter that specifies whether a ResultSet object returned by getResultSet should be closed. The Statement interface defines three constants that can be supplied to the method getMoreResults:
- CLOSE_CURRENT_RESULT — indicates that the current ResultSet object should be closed when the next ResultSet object is returned
- KEEP_CURRENT_RESULT — indicates that the current ResultSet object should not be closed when the next ResultSet object is returned
- CLOSE_ALL_RESULTS — indicates that any ResultSet objects that have been kept open should be closed when the next result is returned
If the current result is an update count and not a ResultSet object, any parameter passed to getMoreResults is ignored.
To determine whether a driver implements this feature, an application can call the
DatabaseMetaData method supportsMultipleOpenResults.
An example:
Statement stmt = conn.createStatement();
boolean retval = cstmt.execute(sql_queries);
ResultSet rs;
int count;
do {
if (retval == false) {
count = stmt.getUpdateCount();
if (count == -1) {
// no more results
break;
} else {
// process update count
}
} else {
rs = stmt.getResultSet();
// process ResultSet
}
retval = stmt.getMoreResults();
while (true);