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rasputyashka wants to merge 3 commits into from
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gh-102058: Update descriptor.rst #102059

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a691073
Update descriptor.rst
rasputyashka Feb 19, 2023
4d15add
Changed single backticks to double ones.
rasputyashka Feb 19, 2023
e240ee1
Update Doc/howto/descriptor.rst
rasputyashka Feb 19, 2023
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11 changes: 10 additions & 1 deletion Doc/howto/descriptor.rst
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Expand Up @@ -853,7 +853,7 @@ be used to implement an `object relational mapping

The essential idea is that the data is stored in an external database. The
Python instances only hold keys to the database's tables. Descriptors take
care of lookups or updates:
care of lookups or updates*:

.. testcode::

Expand All @@ -870,6 +870,15 @@ care of lookups or updates:
conn.execute(self.store, [value, obj.key])
conn.commit()

.. note::
Formatting string is not recommended for building SQL queries.
Since it is just an example and we didn't want to make the code
more complicated (in fact, using them in our example is quite justified),
we decided to use it. You have to validate the data before putting it
into a query string or trust an end-user, which sometimes is not the best
option. Use placeholders instead, as we did in ``WHERE`` clause.


We can use the :class:`Field` class to define `models
<https://en.wikipedia.org/wiki/Database_model>`_ that describe the schema for
each table in a database:
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