Outer joins add the placeholder '---' that is used as some sort of NULL
value.
However select operations on such relations would always fail, because
relations are supposed to only contain values of class rstring, and
the placeholder was added as a regular string.
As a consequence, automatic casting would always fail, and the select
would always raise an exception.
Added a new test case with this specific case in mind.
This introduces several advantages:
No longer rely on the cache to be able to contain as many as
needed. It works within relational but it is not assured to be so if it
is used within other projects.
Using compile flags allows slightly simpler expressions.
Added a button to clear the current session
changed the disposition of the operator buttons, to take up less
vertical space. Now it should be better to fit smaller screens.
Adds some functions to store and load an entire session as a binary
blob.
In this way the user does not need to re-load all the relations from the
previous session.
This is more Pythonic and makes the code more readable.
Backwards compatibility is provided by giving an alias with the
previous name of the class.
It will not be broken until the next major release.
Operations are possible even when the order of the attributes is
not the same. Because ordering is just an implementation detail and
not an actual part of relational algebra.
A _rearrange() function exists to convert relations to have a similar
format and be able to operate on them.
The function would perform a projection in any case, which would cause
the creation of a new temporary relation, even when the relations where
already using the same order of attributes.
This commit fixes the issue by making it return an identity if the
operation is not necessary.
When doing a selection, a new context (in the form of a dictionary)
is created.
Instead of re-using the same dictionary re-assigning the values, now
use a comprehension to avoid redundant reads.
Python3 handles encoding differently, and files are loaded
according to the locale set on the system.
This means that when building on a locale-less chroot,
the tests will always fail because it will try to load utf-8
and encode it as ASCII.
This forces the encoding. The tests are encoded in utf-8 anyway
so any other encoding set by the locale would cause a failure.
Salvo 'LtWorf' Tomaselli