Clarified documentation regarding Oracle's treatment of nulls and empty strings.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@9976 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Ian Kelly 2009-03-05 20:21:22 +00:00
parent 7197a4dcb7
commit ad6ce1e6f9
2 changed files with 9 additions and 8 deletions

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@ -475,12 +475,13 @@ characters of the truncated name with a repeatable MD5 hash value.
NULL and empty strings
----------------------
Django generally prefers to use the empty string ('') rather than NULL, but
Oracle treats both identically. To get around this, the Oracle backend
coerces the ``null=True`` option on fields that permit the empty string as a
value. When fetching from the database, it is assumed that a NULL value in
one of these fields really means the empty string, and the data is silently
converted to reflect this assumption.
Django generally prefers to use the empty string ('') rather than
NULL, but Oracle treats both identically. To get around this, the
Oracle backend coerces the ``null=True`` option on fields that have
the empty string as a possible value. When fetching from the database,
it is assumed that a NULL value in one of these fields really means
the empty string, and the data is silently converted to reflect this
assumption.
``TextField`` limitations
-------------------------

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@ -54,8 +54,8 @@ string, not ``NULL``.
.. note::
When using the Oracle database backend, the ``null=True`` option will be
coerced for string-based fields that can blank, and the value ``NULL`` will
be stored to denote the empty string.
coerced for string-based fields that have the empty string as a possible
value, and the value ``NULL`` will be stored to denote the empty string.
``blank``
---------