Specifications

Adding controls to the form
562 InfoMaker
Adding computed fields to a form
You can use computed fields to perform calculations in the form. Typical uses
of computed fields include:
• Calculations based on column data that change for each retrieved row
For example, if you are retrieving yearly salary, you could define a
computed field that displays monthly salary (defined as Salary / 12).
• Summary statistics
For example, you can use a computed field to calculate the average salary
of all the retrieved rows.
• Concatenated fields
For example, if you are retrieving first name and last name, you can define
a computed field that concatenates the values so that they appear with only
one space between them (defined as Fname + " " + Lname).
• System information
For example, you can place the current date and time in a form by using
computed fields (defined as
Today( ) and Now( ) ).
About defining computed columns and computed fields
When creating a form, you can define computed columns and computed fields:
• In the Select painter, you can define computed columns when you are
defining the
SELECT statement that will be used to retrieve data into the
form
• In the Form painter, you can define computed fields after you have defined
the
SELECT statement
The difference
between the two ways
When you define a computed column in the Select painter, the column’s
definition is part of the
SELECT statement and the value is calculated by the
DBMS when the data is retrieved. The computed column’s value does not
change until data has been updated and retrieved again.
When you define a computed field in the Form painter, the value of the column
is calculated by InfoMaker in the form after the data has been retrieved. The
value changes dynamically as the data in the form changes.
Recommendation
If you want your DBMS to do the calculations on the server before bringing
data down and you do not care about dynamically updating the computed
values, define computed columns as part of the
SELECT statement.