Scrollable Result Sets

Scrollable result sets allow you to move forward and backward through a result set. This type of movement is classified as either relative or absolute. You can position absolutely on any scrollable result set by calling the methods first(), last(), beforeFirst(), afterLast(), and absolute(). Relative positioning is done with the methods next(), previous(), and relative().

A scrollable result set can also either be updateable or read-only. This refers to whether or not you are able to make changes to the underlying database. Another term, sensitivity, refers to whether these changes are reflected in your current result set.

A sensitive result set will reflect any insert, updates, or deletes made to it. In PSQL's case, an insensitive result set does not reflect any changes made to it (it is a static snapshot of the data). In other words, you do not see your updates or those made by anyone else.

Sensitive and insensitive result sets correspond to dynamic and static in ODBC, respectively. A sensitive result set reflects your own changes and can reflect others changes if the transaction isolation level is set to READ_COMMITTED. Transaction isolation is set using the Connection object. The result set type is set upon statement creation.

If your result set is insensitive, then it is possible to make calls to the method getRow() in order to determine your current row number. On an insensitive result set, you can also make calls to isLast(), isFirst(), isBeforeFirst(), and isAfterLast(). On a sensitive result set, you can only make calls to isBeforeFirst() and isAfterLast(). Also, on an insensitive result set, the driver will honor the fetch direction suggested by the user. The driver ignores the suggested fetch direction on sensitive result sets.