IDENTITY on a BitMap column?

Consider the following table
CREATE TABLE Attributes( id int identity(1,1),
name varchar(100),
mask bigint)
Now, attribute mask will be a bit mask of the attribute name. Consider the
data:
id name mask
-- -- --
1 foo 1
2 bar 2
3 mann 4
4 frau 8
5 kein 16
6 alles 32
How do I put a trigger on this table, or something so that I do not have to
worry about the mask when I insert data? Inserting 1 record at a time would
be no problem, just get the MAX of mask and double it. But how to handle
two or more inserts at a time? Should I use an instead-of-trigger?
Sorry about the poor english.
Dieter"Dieter Katzenland" <deiter@.rrtc.com> wrote in
news:#e8DYffjDHA.2964@.tk2msftngp13.phx.gbl:
> How do I put a trigger on this table, or something so that I do not
> have to worry about the mask when I insert data? Inserting 1 record
> at a time would be no problem, just get the MAX of mask and double it.
> But how to handle two or more inserts at a time? Should I use an
> instead-of-trigger?
hi,
in this case it would be enough to let the mask empty on inserting and then
use an AFTER INSERT Trigger for calculating the mask.
--
best regards
Peter Koen
--
MCAD, CAI/R, CAI/S, CASE/RS, CAT/RS
http://www.kema.at|||Assuming that your multi-row INSERT originates from a table or query:
CREATE TABLE foo (name VARCHAR(10) PRIMARY KEY)
INSERT INTO foo VALUES ('Alpha')
INSERT INTO foo VALUES ('Beta')
INSERT INTO Attributes (id, name, mask)
SELECT COUNT(*)+
(SELECT MAX(id) FROM attributes),
A.name,
POWER(2,COUNT(*))*
(SELECT MAX(mask) FROM attributes)
FROM foo AS A
JOIN foo AS B
ON A.name >= B.name
GROUP BY A.name
--
David Portas
--
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