About displaying and validating data
When PowerBuilder generates a basic DataWindow object, it uses the extended
attributes defined for the data and stored in the extended attribute
system tables.
For more information about the extended attribute
system tables, see Appendix A, “The Extended
Attribute System Tables”.
In the Database painter, you can create the extended attribute
definitions that specify a column’s display format, edit
style, and validation rules.
In the DataWindow painter, you can override these extended attribute definitions
for a column in a DataWindow object. These overrides do not change the
information stored with the column definition in the extended attribute
system tables.
Presenting the data
When you generate a new DataWindow object, PowerBuilder presents the data
according to the properties already defined for a column, such as
a column’s display format and edit style.
Display formats
Display formats embellish data values while still displaying
them as letters, numbers, and special characters. Using display
formats, for example, you can:
- Change
the color of numbers to display a negative value - Add parentheses and dashes to format a telephone
number - Add a dollar sign and period to indicate a currency
format
For information, see “Working with display
formats “.
Edit styles
Edit styles usually take precedence over display formats and
specify how column data is presented. For example, using edit styles,
you can:
- Display valid values
in a dropdown list - Indicate that a single value is selected by a check
box - Indicate which of a group of values is selected
with radio buttons
In the DataWindow painter, an edit style is simply a way of presenting
data. You
can change data in a DataWindow object; you cannot change data in a report.
In the Database painter, an edit style enables users to change
data
in the database by means of an edit mechanism, such as a check box
or radio buttons.
For more information, see “Working with edit styles “.
About display format masks
and EditMask masks
The differences between display format masks and EditMask
masks can be confusing. A display format mask determines the appearance
of the column when the focus is off
the column,
or when the DataWindow object is in print preview mode. When you apply
an EditMask edit style, the mask you use determines the appearance
of the column when focus is on
the column.
If you want data to display differently depending on whether
the focus is on or off the column, specify an edit mask (on the
Edit property page for the column) as well a display format (on
the Format property page for the column), then check the Use Format
check box on the Format property page.
Validating data
When data is entered in the Database painter or in a DataWindow object, PowerBuilder evaluates
the data against validation rules defined for that column. If the
data is valid, PowerBuilder accepts the entry; otherwise, PowerBuilder displays
an error message and does not accept the entry.
For more information, see “Working with validation
rules “.