Setting DataWindow data with a DataWindow data expression – PB Docs 2019

When you set data in a DataWindow control, the datatypes of the
source values must match the datatypes of the columns being
set.

Single value or an array

When your data expression refers to a single row and column, you
can set the value in the DataWindow control with a value that matches
the column’s datatype. When you are setting values in a single column
and specifying an expression that can refer to multiple rows, the
values you assign must be in an array of the appropriate
datatype.

Multiple columns and whole
rows

When the expression refers to more than one column, you can
assign the data with a structure or user object to the DataWindow
data. When you create the definition, the fields (in a structure) or
instance variables (in a user object) must match the columns. There
must be the same number of fields or variables, defined in the same
order as the columns, with compatible datatypes.

When your expression can refer to multiple rows, you need an
array of the structure or user object.

Using arrays to set
values

You do not have to know in advance how many rows are involved
when you are setting data in the DataWindow control. PowerBuilder uses
the number of elements in the source array and the number of rows in
the target expression to determine how to make the assignment and
whether it is necessary to insert rows.

If the target expression is selected rows or a range of rows,
then:

If the target expression is all rows but not all columns,
then:

Inserting new rows

When you are setting data and you specify a range, then if rows
do not exist in that range, rows are inserted to fill the range. For
example, if the DataWindow control has four rows and your expression
says to assign data to rows 8 through 12, then eight more rows are
added to the DataWindow control. The new rows use the initial default
values set up for each column. After the rows are inserted, the array
of source data is applied to the rows as described above.

Examples

These examples refer to a DataWindow object that has three
columns: emp_id, emp_lname, and salary. The window declares these
arrays as instance variables and the window’s Open event assigns four
elements to each array:

The uo_empdata user object has three instance variables: id,
name, and salary. The uo_empid_name user object has two instance
variables: id and name.

This example sets emp_lname in the selected rows to the values
of is_name, an array with four elements. If two rows are selected,
only the first two values of the array are used. If six rows are
selected, the last two rows of the selection are set to an empty
string:

This example sets salary in rows 8 to 12 to the values in the
array id_salary. The id_salary array has only four elements, so the
extra row in the range is set to 0 or a default value:

This statement resets the DataWindow control and inserts four
rows to match the array elements of iuo_data:

This example sets columns 1 and 2 in rows 5 to 8 to the values
in the array iuo_id:

This example sets emp_id in the first four rows to the values in
the ii_id array. Rows 5 through 12 are not affected: