Usually you retrieve data into a DataWindow object from the database, because the data is changeable and you want the latest information. However, sometimes the data you display in a DataWindow object almost never changes (as in a list of states or provinces), and sometimes you need a snapshot of the data at a certain point in time. In these situations, you can store the data in the DataWindow object itself.
Storing data in a DataWindow object is also a good way to share data and the DataWindow definition with other developers. They can simply open the DataWindow object on their computers to get the data and all its properties.
Data stored in a DataWindow object is stored within the actual object itself, so when a window opens showing such a DataWindow, the data is already there. There is no need to issue Retrieve to get the data.
PocketBuilder never retrieves data into a drop-down DataWindow that already contains data. For all other DataWindow objects, if you retrieve data into a DataWindow object stored with data, PocketBuilder handles it the same as a DataWindow object that is not stored with data: PocketBuilder gets the latest data by retrieving rows from the database.
The most common reason to store data in a DataWindow object is for use as a drop-down DataWindow where the data is not coming from a database. For example, you might want to display a list of postal codes for entering values in a State or Province column in a DataWindow object. You can store those codes in a DataWindow object and use the DropDownDataWindow edit style for the column.
For more information about using the DropDownDataWindow edit style, see Chapter 21, “Displaying and Validating Data.”
To store data in a DataWindow object:
If the Data view is not already displayed, select View>Data from the menu bar.
In the default layout for the DataWindow painter, the Data view displays in a stacked pane under the Properties view. All columns defined for the DataWindow object are listed at the top.
Do any of the following:
Click the Insert Row button in the PainterBar to create an empty row and type a row of data. You can enter as many rows as you want.
Click the Retrieve button in the PainterBar to retrieve all the rows of data from the database. You can delete rows you do not want to save or manually add new rows.
Click the Delete button in the PainterBar to delete unwanted rows.
When you have finished, save the DataWindow object.
When you save the DataWindow object, the data is stored in the DataWindow object.
To see changes you make in the Data view reflected in the Preview view, select ShareData from the pop-up menu in the Data view. The Preview view shows data from the storage buffer associated with the Data view.
After you save the DataWindow object with data to obtain a snapshot, you sometimes need to save it again without data. To do so, select Delete All Rows from the pop-up menu in the Data view before saving.
| Copyright © 2004. Sybase Inc. All rights reserved. |
|
|
