Nullable fields in a View

Question

I am having issues trying to get the nullable attribute of a view to be "No". I created a very simple view to test, and the issue I am running into is anytime I specify a Union in the query every field in the view is set to nullable. In this very simple example I am querying 3 columns from a table, none of which are nullable. If I do not include a union then the view fields fields are not nullable as expected, however as soon as I introduce the union (even though no possiblity of null values are introduced) the columns change to being nullable. In this simple example it isn't such a big deal, but this is causing significant performance implications using LINQ to query more complex views. Any help would be much appreciated.
Example 1:
SELECT comp_id, comp_typ_id
from component
where comp_id = 1
--Columns of resulting View
Column_name: comp_id      
Data_Type: NUMBER(5,0)
Nullable: No
Column_name: comp_typ_id      
Data_Type: NUMBER(5,0)
Nullable: No
Example 2:
SELECT comp_id, comp_typ_id
from component
where comp_id = 1
UNION
SELECT comp_id, comp_typ_id
from component
where comp_id = 2
--Columns of resulting View
Column_name: comp_id      
Data_Type: NUMBER(5,0)
Nullable: Yes
Column_name: comp_typ_id      
Data_Type: NUMBER(5,0)
Nullable: Yes
Edited by: 916327 on Feb 22, 2012 12:15 PM
Edited by: 916327 on Feb 22, 2012 12:21 PM
Edited by: 916327 on Feb 22, 2012 12:42 PM
Edited by: 916327 on Feb 22, 2012 12:48 PM

Answer 1

916327 wrote:
I am having issues trying to get the nullable attribute of a view to be "No". I created a very simple view to test, and the issue I am running into is anytime I specify a Union in the query every field in the view is set to nullable. In this very simple example I am querying 3 columns from a table, none of which are nullable. If I do not include a union then the view fields fields are not nullable as expected, however as soon as I introduce the union (even though no possiblity of null values are introduced) the columns change to being nullable.
Example 1:
SELECT week_nbr,
period_nbr,
year_nbr
FROM time_hierarchy
WHERE d_date = '03-JAN-99';HUH?
The purpose of TO_DATE is to convert string datatype to DATE datatype.
With Oracle characters between single quote marks are STRINGS!
'This is a string, 2009-12-31, not a date'
When a DATE datatype is desired, then use TO_DATE() function including format.
'10-11-12'
Which is correct DATE below for string above?
Oct. 11 2012
Nov. 10 2012
Nov. 12 2010
Dec. 11 2010
Oct. 12 2011
Dec. 10 2011
I'll give you 6 guesses, since the first 5 will be incorrect.