~~NOTOC~~
====== Does a field exist? ======
Build an [[Expression Builder|expression]]. If the expression returns a value when this action runs the evaluation will pass. If it does not return a value the evaluation will fail.

===== Explanation =====
Evaluations have two [[Automation Trigger|automation triggers]] associated with them : Then and Else.  Actions under the "Then" automation trigger execute when the evaluation passes, and actions under the "Else" automation execute when the evaluations fails.

{{ ::action_evaluation_drop.png?direct |}}

Field exists evaluations are used to execute a set of actions if certain expression returns a value, and another set of actions if it does not.

Example : Suppose an application contains a [[Table|table]] for Contacts with three fields, First Name, Last Name and Contact Name.  When creating a Contact the First Name field is not required, and so it could be blank.  When it's blank the builder wants the Contact Name to be just the Last Name, but when there is a First Name they want it to be "Last Name, First Name".  To accomplish the difference, they would create a field exists action and choose the First Name field in the expression.  If it has a value, then combine First and Last Name in a [[Action Type - Set Field Value|set field value]] action; if not then just copy Last Name into Contact Name.
===== Settings =====
==== Choose a field or build an expression ====
If the expression returns a value when this action runs the evaluation will pass. If it does not return a value the evaluation will fail.

{{ ::action_fieldexists_expression.png?direct |}}

==== Describe this action ====
Useful as a comment, this description will overwrite the automatically generated description in the [[Action Manager|Action Manager]].
==== Queue this action and children	 ====
When an action is [[Action Queue|queued]], the subsequent actions continue to process without it. Meanwhile, the queued action and its children process separately. Queue actions that you don't want a user to wait for.