Nulls in Dates

Question

We are working with the beta release 3.0c of Forte and 2.0c of express. We
have several DateTime domain fields for which we need to have nulls carried
through and updated on the data base. Ideally when the user selects the
insert button and the new record is initialized we would like to place
nulls in those fields before the display and then have those nulls
maintained through the data base update. If the user keys a valid date in
one or more of those fields then the non-null date values would be carried.
Conversely, if a date is present we would like to be able to have the user
delete the date field resulting in nulls being carried forward.
We have made several attempts to null these date fields
(PlaceValueInDisplayField, SetValuesInNewRecord, overriding the
InsertRecordIntoResultSet method, overriding the newobject method) with no
success.
Has anyone been successful in nulling date fields? Thanks.

Answer 1

Donald R. Smith wrote:
>
We are working with the beta release 3.0c of Forte and 2.0c of
express. We
have several DateTime domain fields for which we need to have nulls
carried
through and updated on the data base. Ideally when the user selects
the
insert button and the new record is initialized we would like to place
nulls in those fields before the display and then have those nulls
maintained through the data base update. If the user keys a valid
date in
one or more of those fields then the non-null date values would be
carried.
Conversely, if a date is present we would like to be able to have the
user
delete the date field resulting in nulls being carried forward.
We have made several attempts to null these date fields
(PlaceValueInDisplayField, SetValuesInNewRecord, overriding the
InsertRecordIntoResultSet method, overriding the newobject method)
with no
success.
Has anyone been successful in nulling date fields? Thanks.gbkhor wrote:
1. Create a new domain class say, NewDateTimeNullable which superclass
is DateTimeNullable.
2. At the NewDateTimeNullable Init() method, do Self.IsNull = TRUE this
will set the initial value to null.
Ideally when the user selects the insert button and the new record is initialized we would like to
place nulls in those fields before the display and then have those nulls maintained through the data
base update.3. At the Application modal(Express), for all the datetime class which
would like to behave like you mention above, change the data type to
NewDateTimeNullable.
If the user keys a valid date in one or more of those fields then the non-null date values would be carried.
Conversely, if a date is present we would like to be able to have the user delete the date field resulting
in nulls being carried forward.4. Upon insertion or save do check
- If Variable.IsNull then
else If Variable.IsEqual('') then
Variable.IsNull = TRUE;
end if;
end if;
Hope this will help.
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