Use the
Conditions
tab to enter or revise an Access When
condition rule that can be expressed as a single Boolean expression, or the conjunction
(
AND
or
OR
) of one or more Boolean expressions.
Each node on the conditions tree defines a single comparison or other condition that
evaluates to
True
or
False
. The Access When condition rule
evaluates to
True
only if all nodes evaluate to true. While the order of
nodes may affect computational performance, order does not affect the outcome of the Access
When condition rule evaluation. Use these options:
The conditions and logical operators
you enter on this tab also appear on the
Advanced
tab's
Condition
array and
Logic String
field.
Procedure-
To create the first expression, perform the following actions:
-
Double-click the link below the When node.
-
The
Condition
dialog appears, and contains the default
condition, which compares two values.
-
Enter properties, literal constants, or function calls and parameters in the
fields, and select a relational operator.
- Optional:
Select the down arrow at the end of the row for a list of standard conditions
(derived from function alias rules). Open it by clicking the
Open
icon.
If you select
[expression evaluates to true], use the
Expression Builder for guided assistance.
- Optional:
Click
OK
to close the dialog and display the condition on
the tree.
-
To add, edit, or delete conditions, or to create groups of nested conditions:
-
Open the
Actions
menu next to the node.
- Right-click the node.
You can use the following options:
-
Edit
- Update the condition.
-
Insert Condition
-
Add a condition beneath the selected node. When you close the dialog, an
AND
or
OR
logical operator appears to the left
of the new node. You can toggle between them by clicking the operator. Changing one
value changes all of them at the same node level.
-
Insert Group
-
Create a group of nested conditions. Enter a name in the
Group
Label
field to help identify the group on the tree. When you close the
dialog, the condition is indented beneath the node above it. Use the expand and
collapse icons to display or hide the nodes within the group. When collapsed, only
the label is displayed. To edit the label, select it on the tree and choose the
Edit
menu option. You can nest groups at multiple levels;
for example:
A AND B AND (C OR (E AND F)).
- Delete
- Delete the expression node. Node groups nested beneath it are also deleted.