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The fitler conditions is defined in the ``General`` tab.
The ``Conditions`` are used to select a sub-sample of the history records. It
is based on the smart_query_ available in the Web2py_ framework. The query
is written in the natural language, but it is limited to field of the
history table. Foreign tables fields, virtual fields or keys of the
``history.data`` dictionary can not be used.
The ``changelog`` event introduced earlier has the ``id`` equal to 7. To
select history related changelog events, enter:
history.id_events = 7
Possible operators are given :ref:`Appendix E`.