What is the sql way to restrict "superadmin" priv to one user?

[Perttu Pulkkinen]

Is there some way to restrict in mysql that certan field has only ONE ROW
with CERTAIN VALUE X while other rows can have any values but not this
one(so "unique" is not the answer..)?

This can be of course done in application level, but it would just be nice
to know. I would build my application so that only one user can be
superadmin, while others are normal admins or something else.

Of course this restriction would not be enough anyway, because I still need
to figure out what happens in different cases. So actual benefit would be
close to zero, but nerd idealist inside of me requires to know - "we have a
right to know".

[Bill Karwin]

Perttu Pulkkinen wrote:

Is there some way to restrict in mysql that certan field has only ONE ROW
with CERTAIN VALUE X while other rows can have any values but not this
one(so "unique" is not the answer..)?

From what I have read in the docs, MySQL does not appear to have
support for user-defined constraints, as some RDBMS implementations do.
I recommend you go ahead and implement the constraint in your
application logic.

Regards,
Bill K.

[Bill Karwin]

Perttu Pulkkinen wrote:

Is there some way to restrict in mysql that certan field has only ONE ROW
with CERTAIN VALUE X while other rows can have any values but not this
one(so "unique" is not the answer..)?

From what I have read in the docs, MySQL does not appear to have
support for user-defined constraints, as some RDBMS implementations do.
I recommend you go ahead and implement the constraint in your
application logic.

Regards,
Bill K.