On Wednesday, January 2, 2019, Rich Shepard <
rshepard@appl-ecosys.com> wrote:
On Wed, 2 Jan 2019, David G. Johnston wrote:
There is no magic name logic involved. A domain is just a type with
inherent constraints that are user definable. You make use of it like any
other type.
Create table tbl (
column_name state_code not null
)
Values stored in column_name are now of type state_code and constrained to
be one of the check constraint values.
David,
I'm not following you. I have two tables each with a column,
state_code char(2) NOT NULL.
Do you mean that I need to write the column constraint for each table? If
not, I don't see from your response how to implement the multi-table
constraint for this column.
That is a char(2) column for which ‘??’ is a valid value. The fact that it is named state_code is immaterial; the domain that you created doesn’t get used. There is no magic linking just by virtue of using the same name.
Change char(2) to state_code if you wish to apply the domain on the column.
David J.