JdbcRowSet
must implement. ResultSet
object that makes it possible to use the result set as a JavaBeans™ component. Thus, a JdbcRowSet
object can be one of the Beans that a tool makes available for composing an application. Because a JdbcRowSet
is a connected rowset, that is, it continually maintains its connection to a database using a JDBC technology-enabled driver, it also effectively makes the driver a JavaBeans component. Because it is always connected to its database, an instance of JdbcRowSet
can simply take calls invoked on it and in turn call them on its ResultSet
object. As a consequence, a result set can, for example, be a component in a Swing application.
Another advantage of a JdbcRowSet
object is that it can be used to make a ResultSet
object scrollable and updatable. All RowSet
objects are by default scrollable and updatable. If the driver and database being used do not support scrolling and/or updating of result sets, an application can populate a JdbcRowSet
object with the data of a ResultSet
object and then operate on the JdbcRowSet
object as if it were the ResultSet
object.
JdbcRowSet
ObjectJdbcRowSet
interface, JdbcRowSetImpl
, provides an implementation of the default constructor. A new instance is initialized with default values, which can be set with new values as needed. A new instance is not really functional until its execute
method is called. In general, this method does the following: PreparedStatement
object and sets any of its placeholder parameters ResultSet
object execute
method is successful, it will set the appropriate private JdbcRowSet
fields with the following: Connection
object -- the connection between the rowset and the database PreparedStatement
object -- the query that produces the result set ResultSet
object -- the result set that the rowset's command produced and that is being made, in effect, a JavaBeans component execute
method has not executed successfully, no methods other than execute
and close
may be called on the rowset. All other public methods will throw an exception. Before calling the execute
method, however, the command and properties needed for establishing a connection must be set. The following code fragment creates a JdbcRowSetImpl
object, sets the command and connection properties, sets the placeholder parameter, and then invokes the method execute
.
JdbcRowSetImpl jrs = new JdbcRowSetImpl(); jrs.setCommand("SELECT * FROM TITLES WHERE TYPE = ?"); jrs.setURL("jdbc:myDriver:myAttribute"); jrs.setUsername("cervantes"); jrs.setPassword("sancho"); jrs.setString(1, "BIOGRAPHY"); jrs.execute();The variable
jrs
now represents an instance of JdbcRowSetImpl
that is a thin wrapper around the ResultSet
object containing all the rows in the table TITLES
where the type of book is biography. At this point, operations called on jrs
will affect the rows in the result set, which is effectively a JavaBeans component. The implementation of the RowSet
method execute
in the JdbcRowSet
reference implementation differs from that in the CachedRowSet
™ reference implementation to account for the different requirements of connected and disconnected RowSet
objects.
@author Jonathan Bruce
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