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java.sql
package and, as of the version 1.4 release, is included in the JavaTM 2 SDK, Standard Edition.
See:
Description
| Interface Summary | |
| DataSource | A factory for connections to the physical data source that this
DataSource object represents. |
| RowSet | The interface that adds support to the JDBC API for the JavaBeansTM component model. |
| RowSetInternal | The interface that a RowSet object implements in order to
present itself to a RowSetReader or RowSetWriter
object. |
| RowSetListener | An interface that must be implemented by a
component that wants to be notified when a significant
event happens in the life of a RowSet object. |
| RowSetMetaData | An object that contains information about the columns in a
RowSet object. |
| RowSetReader | The facility that a disconnected RowSet object calls on
to populate itself with rows of data. |
| RowSetWriter | An object that implements the RowSetWriter interface,
called a writer. |
| Class Summary | |
| RowSetEvent | An Event object generated when an event occurs to a
RowSet object. |
Provides the API for data source access and manipulation of tabular data
as JavaBeans.
This package was originally developed as a supplement to java.sql
package and, as of the version 1.4 release, is included in the JavaTM 2 SDK, Standard Edition. It remains an essential
part of the Java 2 SDK, Enterprise Edition (J2EETM).
The javax.sql package in the JDBC for CDC/FP Optional Package
provides for the following:
DataSource interface as an alternative to the
DriverManager for establishing a connection with
a data source Applications use the DataSource and RowSet
APIs directly.
DataSource Object to Make a Connectionjavax.sql package provides the preferred way to make
a connection with a data source. The DriverManager class, the
original mechanism, is still valid, and code using it will continue to run.
However, the newer DataSource mechanism is preferred because
it offers many advantages over the DriverManager mechanism.
These are the main advantages of using a DataSource object
to make a connection in the CDC environment:
.Driver vendors provide DataSource implementations. A particular
DataSource object represents a particular physical data source,
and each connection the DataSource object creates is a connection
to that physical data source.
It is possible to use a DataSource object directly to create a
connection. An application can create an instance of a DataSource,
set the neccessary properties and create a Connection object. The
following code fragment demonstrates:
// create an instance of the vendors data source
DataSource ds = new VendorDataSource();
// now set the properties
ds.setServerName("dbServer.acct");
ds.setPortNumber(1234);
// get a connection
Connection conn = ds.getConnection(user, pass);
The properties that are needed to connect using a particular DataSource
will depend on the implementation. The JDBC 3.0 API Specification lists the
properties that every driver must support. (see Package Specification below)
RowSet interface works with various other classes and
interfaces behind the scenes. These can be grouped into three categories.
RowSetListenerRowSet object is a JavaBeansTM
component because it has properties and participates in the JavaBeans event
notification mechanism. The RowSetListener interface is implemented
by a component that wants to be notified about events that occur to a particular
RowSet object. Such a component registers itself as
a listener with a rowset via the RowSet.addRowSetListener method.
When the RowSet object changes one of its rows, changes
all of it rows, or moves its cursor, it also notifies each listener that
is registered with it. The listener reacts by carrying out its implementation
of the notification method called on it.
RowSetEventRowSet object
creates an instance of RowSetEvent and passes it to the listener.
The listener can use this RowSetEvent object to find out which
rowset had the event.
RowSetMetaDataResultSetMetaData interface,
provides information about the columns in a RowSet object. An
application can use RowSetMetaData methods to find out how many
columns the rowset contains and what kind of data each column can contain.
The RowSetMetaData interface provides methods for
setting the information about columns, but an application would not normally
use these methods. When an application calls the RowSet method
execute, the RowSet object will contain
a new set of rows, and its RowSetMetaData object will have
been internally updated to contain information about the new columns.
RowSet object that implements the RowSetInternal
interface can call on the RowSetReader object associated with
it to populate itself with data. It can also call on the RowSetWriter
object associated with it to write any changes to its rows back to the data
source from which it originally got the rows. A rowset that remains connected
to its data source does not need to use a reader and writer because it can
simply operate on the data source directly.
RowSetInternalRowSetInternal interface, a RowSet
object gets access to its internal state and is able to call on its reader
and writer. A rowset keeps track of the values in its current rows and of
the values that immediately preceded the current ones, referred to as the
original values. A rowset also keeps track of (1) the parameters
that have been set for its command and (2) the connection that was passed
to it, if any. A rowset uses the RowSetInternal methods behind
the scenes to get access to this information. An application does not normally
invoke these methods directly.
RowSetReaderRowSet object that has implemented the RowSetInternal
interface can call on its reader (the RowSetReader object associated
with it) to populate it with data. When an application calls the RowSet.execute
method, that method calls on the rowset's reader to do much of the work.
Implementations can vary widely, but generally a reader makes a connection
to the data source, reads data from the data source and populates the rowset
with it, and closes the connection. A reader may also update the RowSetMetaData
object for its rowset. The rowset's internal state is also updated, either
by the reader or directly by the method RowSet.execute.
RowSetWriterRowSet object that has implemented the RowSetInternal
interface can call on its writer (the RowSetWriter object associated
with it) to write changes back to the underlying data source. Implementations
may vary widely, but generally, a writer will do the following:
The RowSet interface may be implemented in any number of
ways, and anyone may write an implementation. Developers are encouraged
to use their imaginations in coming up with new ways to use rowsets.
javax.sql
package:
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