On 12/17/2018 02:20 PM, Rich Shepard wrote:
On Mon, 17 Dec 2018, Melvin Davidson wrote:
Yes, you must drop then add the revised constraint. However, from your
statement above, it sounds to me as if you would be better off using A
FOREIGN kEY CONSTRAINT. It makes things a lot simpler.
Melvin,
I don't follow. Here's the DDL for that column:
industry varchar(24) NOT NULL
CONSTRAINT invalid_industry
CHECK (industry in ('Agriculture', 'Business, other', 'Chemicals',
'Energy', 'Law', 'Manufacturing', 'Mining', 'Municipalities',
'Ports/Marine Services', 'Transportation')),
and I want to remove Municipalities for the more general Government.
Melvin is saying to:
1. create a table named valid_industry,
2. populate it with the valid industries,
3. create an FK constraint on your main table's industry column to
valid_industry.industry, and then
4. drop the constraint invalid_industry.
--
Angular momentum makes the world go 'round.
