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Remove redundant drop function doc section 

Drop function description was moved up adjacent to the other
functions to provide better document flow making this section
redundant, hence its removal.
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Steve Malmskog 2018-04-26 20:35:41 -07:00 committed by Alec Grieser
parent 61666fc5b0
commit b1440e5a70
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documentation/sphinx/source/class-scheduling.rst
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@ -247,23 +247,6 @@ Idempotence
Occasionally, a transaction might be retried even after it succeeds (for example, if the client loses contact with the cluster at just the wrong moment). This can cause problems if transactions are not written to be idempotent, i.e. to have the same effect if committed twice as if committed once. There are generic design patterns for :ref:`making any transaction idempotent <developer-guide-unknown-results>`, but many transactions are naturally idempotent. For example, all of the transactions in this tutorial are idempotent.
Dropping with limited seats
---------------------------
Let's finish up the limited seats feature by modifying the drop function:
.. code-block:: python
:emphasize-lines: 4,5
@fdb.transactional
def drop(tr, s, c):
rec = attends.pack((s, c))
if not tr[rec].present(): return # not taking this class
tr[course.pack((c,))] = fdb.tuple.pack((fdb.tuple.unpack(tr[course.pack((c,))])[0] + 1,))
del tr[rec]
This case is easier than signup because there are no constraints we can hit. We just need to make sure the student is in the class and to "give back" one seat when the student drops.
More features?!
---------------