[QGIS-Developer] issues with constraints(?)

[Giovanni Manghi]

Hi all,

I have some questions on table/attributes constraints, not sure if it
is me I don't understand how they work or if they are issues. I would
appreciate a clarification.

1) they seem to work while adding a new feature or when updating the
attributes using feature form that opens using the identify tool, but
not they do not work in the table of attributes both in table view or
form view. Is this expected?

2) the "not null" constraint works if the attribute shows "NULL" while
does not not if the cell is empty. While I understand the difference
between NULL and empty, for the vast majority of users NULL=empty. Is
this the intended behavior or is a bug? if it is the former than I
would suggest add a "not empty" option

3) I have difficulties in understand how the "expression" and
"expression description" work: if I choose a column for the former and
fill the latter (that is optional) with some kind of text, then when
reopening the vector properties I find the description in the
"expression" and the column name in the "expression description".

thanks in advance

-- G --