Computed columns in
a table contain data values that are derived from other columns in
the table. Staged tables contain computed columns for data that is
not directly provided by the raw data source but the data might be
useful for reporting or promoting consistency across various data
sources. For example, a data source normally has a datetime stamp
and from that datetime stamp, SAS IT Resource Management might provide
a computed column that calculates weeks or months.
Note: A computed column should
not be used as a source of calculations for other computed columns.
Using a computed column as a source for a computation can be problematic
because the order of computing the values for the computed column
is not guaranteed.
To find a computed column
in a staged table and view the formula that it uses, right-click the
staged table in a process flow diagram and select
Properties. Then, open the
Columns tab of the staged
table's
Properties dialog box. This method
is the only way to view the
Expression column.
Note: If you open a table from
a folder view or from the IT Data Marts view, and select the
Columns tab, the columns of the table are displayed.
However, the expressions that are associated with the columns are
not displayed.
All computed columns
contain a formula or expression in the
Expression column of the grid. You can double-click an expression to modify
it for the column. To open the Expression Builder, click the ellipsis
button in the cell. For information about how to work with the Expression
Builder, click
Help in the
Expression Builder
window.
Note: Aggregation tables also use computed
columns. You can use the computed columns that are provided for these
tables and you can create your own.
For more information
about creating and using computed columns, see Specify Computed Columns.