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Because a CachedRowSet object stores data in memory, the amount of data that it can contain at any one time is determined by the amount of memory available. To get around this limitation, a CachedRowSet object can retrieve data from a ResultSet object in chunks of data, called pages. To take advantage of this mechanism, an application sets the number of rows to be included in a page using the method setPageSize. In other words, if the page size is set to five, a chunk of five rows of data will be fetched from the data source at one time. An application can also optionally set the maximum number of rows that may be fetched at one time. If the maximum number of rows is set to zero, or no maximum number of rows is set, there is no limit to the number of rows that may be fetched at a time.After properties have been set, the CachedRowSet object must be populated with data using either the method populate or the method execute. The following lines of code demonstrate using the method populate. Note that this version of the method takes two parameters, a ResultSet handle and the row in the ResultSet object from which to start retrieving rows. CachedRowSet crs = new CachedRowSetImpl(); crs.setMaxRows(20); crs.setPageSize(4); crs.populate(rsHandle, 10); When this code runs, crs will be populated with four rows from rsHandle starting with the tenth row.The next code fragment shows populating a CachedRowSet object using the method execute, which may or may not take a Connection object as a parameter. This code passes execute the Connection object conHandle.Note that there are two differences between the following code fragment and the previous one. First, the method setMaxRows is not called, so there is no limit set for the number of rows that crs may contain. (Remember that crs always has the overriding limit of how much data it can store in memory.) The second difference is that the you cannot pass the method execute the number of the row in the ResultSet object from which to start retrieving rows. This method always starts with the first row. CachedRowSet crs = new CachedRowSetImpl(); crs.setPageSize(5); crs.execute(conHandle); After this code has run, crs will contain five rows of data from the ResultSet object produced by the command for crs. The writer for crs will use conHandle to connect to the data source and execute the command for crs. An application is then able to operate on the data in crs in the same way that it would operate on data in any other CachedRowSet object. .....

Java

Topic: JDBC

Explain Paging Data?

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Java

Topic: JDBC

Explain Paging Data?

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