.. _change-rules-define-concepts-term:

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Change Rules - Defining Concepts
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You can use changes rules to enter the logic you need to define a core business concept within AgileData.

They use the standard AgileData :ref:`natural-language-rules-term` format to change data and populate it into a Concept.


Concept Rules Use Cases
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Simple Concept Rules
--------------------
A simple concept rule is one where the unique concept is derived from a single field in a history table.

Given a ....

And .....

Then ....

Complex Concept Rules
---------------------
There are a number of use cases where the rule to populate a concept may be more complex than the simple use case

Multiple history fields
+++++++++++++++++++++++
When you need to select multiple history fields to determine a unique identifier for a concept due to the history table holding ???

Given a .....
Single Table Relationship...
Then ...

Multiple system of record sources for a single concept
++++++++++++++++++++++++++++++++++++++++++++++++++++++

Often the concept, for example Customer, will be evident in multiple
systems of record, for example a operational system, a CRM, or a financial system.

In this use case there are a number of options on how you define and populate your customer concepts