Java Database Connectivity

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Todd James
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1 Java Database Connectivity ADVANCED FEATURES Dr. Syed Imtiyaz Hassan Assistant Professor, Deptt. of CSE, Jamia Hamdard (Deemed to be University), New Delhi, India.

2 Agenda Scrollable Resultset Updatable Resultset Cursor & Holdability Optinal Package Connection Pooling JNDI Datasource Rowset Summary References

3 Resultset Interface Provides methods for retrieving and manipulating the results of executed queries Scrollable Can move both forward and backward relative to the current position Can move to an absolute position Updatable Can be updated Reflects changes made to the underlying data source while the result set remains open Characteristics Type Concurrency cursor holdability

4 Resultset Interface (cont.) Determines the level of functionality in two areas The ways in which the cursor can be manipulated How concurrent changes made to the underlying data source are reflected by the ResultSet object

5 Resultset Interface Type Resultset Type Description ResultSet.TYPE_FORWARD_ONLY The result set cannot be scrolled; its cursor moves forward only, from before the first row to after the last row. ResultSet.TYPE_SCROLL_INSENSITIVE The result can be scrolled; its cursor can move both forward and backward relative to the current position, and it can move to an absolute position. The result set is insensitive to changes made to the underlying data source while it is open. ResultSet.TYPE_SCROLL_SENSITIVE The result can be scrolled; its cursor can move both forward and backward relative to the current position, and it can move to an absolute position. The result set reflects changes made to the underlying data source while the result set remains open.

6 Resultset Interface Cursors next() previous() first() last() beforefirst() afterlast() relative(int rows) absolute(int row) Program ScrollableResultSetClass

7 Resultset Interface Concurrency Determines what level of update functionality is supported Concurrency Description ResultSet.CONCUR_READ_ONLY The ResultSet object cannot be updated using the ResultSet interface. ResultSet.CONCUR_UPDATABLE The ResultSet object can be updated using the ResultSet interface.

8 Resultset Interface Scrollable Java Program Scrollable ResultSet Oracle 8i Statement stmt = con.createstatemen( ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCURR_READ_ONLY); ResultSet rset = stmt.executequery(); Cache Cursor Table rset.absolute(2);... next() previous() relative() absolute() first() last()

9 Resultset Interface Scrollable & Updatable Statement createstatement(int resultsettype, int resultsetconcurrency) PreparedStatement preparestatement(string sql, int resultsettype, int resultsetconcurrency)

10 Resultset Interface APIs void deleterow(int row) throws SQLException void updatexxx(int idx, XXX x) throws SQLException void updaterow() throws SQLException void movetoinsertrow () throws SQLException void movetocurrentrow() throws SQLException void insertrow() throws SQLException Program UpdatableResultSetClass

11 Resultset Interface Cursor Holdability Calling the method Connection.commit can close the ResultSet objects In some cases, however, this may not be the desired behavior. The ResultSet property holdability gives the application control over whether ResultSet objects (cursors) are closed when commit is called.

12 Resultset Interface Cursor Holdability (cont.) Holdability HOLD_CURSORS_OVER_COMMIT CLOSE_CURSORS_AT_COMMIT Description ResultSet cursors are not closed; they are holdable: they are held open when the method commit is called. Holdable cursors might be ideal if your application uses mostly read-only ResultSet objects. ResultSet objects (cursors) are closed when the commit method is called. Closing cursors when this method is called can result in better performance for some applications. prepstmt = con.preparestatement(sql, ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE, ResultSet.CLOSE_CURSORS_AT_COMMIT);

13 JDBC API Core package (java.sql package) Optional Package (javax.sql package)

14 Core package

15 Optional package Connection Pool DataSource JNDI RowSets

16 Connection Pool

17 Data Source

18 JNDI

19 Overall Picture

20 RowSet

21 RowSet (cont.)

22 Summary

23 References JDBC Basics

24 Thank You SRC:

JDBC 3.0. Java Database Connectivity. 1 Java

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