I want to create a table with "WITH CHECK OPTION" - sql

Question

create table STAFF
(StaffID TINYINT IDENTITY NOT NULL,
fName varchar(20) NOT NULL,
lname varchar(20) NOT NULL,
Phone varchar(10) NOT NULL,
Gender char(01),
DoB date NOT NULL,
Mentor TINYINT,
Payment_ID TINYINT NOT NULL,
constraint staff_pk primary key (StaffID),
constraint staff_fk foreign key (Payment_ID) references PAYMENT(Payment_ID),
constraint mentor_fk foreign key (Mentor) references staff(StaffID)
For the Gender column I want to insert ONLY 'M','F','O' characters only.
How can I do with this the "WITH CHECK OPTION"

Answer 1

I don't think you want with check option. You want a check constraint:
alter table staff
add constraint chk_staff_gender check (gender in ('M', 'F', 'O'));
(You can put this in the create table statement as well.)
with check option is an option on views that ensures that data remains consistent even when the data in underlying tables changes (see here) .

Answer 2

add , constraint gender_chk check (Gender in ('M','F','O'))
the with check option is on by default.
create table STAFF
(StaffID TINYINT IDENTITY NOT NULL,
fName varchar(20) NOT NULL,
lname varchar(20) NOT NULL,
Phone varchar(10) NOT NULL,
Gender char(01),
DoB date NOT NULL,
Mentor TINYINT,
Payment_ID TINYINT NOT NULL,
constraint staff_pk primary key (StaffID)
constraint staff_fk foreign key (Payment_ID) references PAYMENT(Payment_ID),
constraint mentor_fk foreign key (Mentor) references staff(StaffID)
, constraint gender_chk check (Gender in ('M','F','O'))
)
From the MSDN Documentation for ALTER TABLE (emphasis added):
WITH CHECK | WITH NOCHECK
Specifies whether the data in the table is or is not validated against a newly added or re-enabled FOREIGN KEY or CHECK constraint. If not specified, WITH CHECK is assumed for new constraints, and WITH NOCHECK is assumed for re-enabled constraints.
If you do not want to verify new CHECK or FOREIGN KEY constraints against existing data, use WITH NOCHECK. We do not recommend doing this, except in rare cases. The new constraint will be evaluated in all later data updates. Any constraint violations that are suppressed by WITH NOCHECK when the constraint is added may cause future updates to fail if they update rows with data that does not comply with the constraint.
The query optimizer does not consider constraints that are defined WITH NOCHECK. Such constraints are ignored until they are re-enabled by using ALTER TABLE table WITH CHECK CHECK CONSTRAINT ALL.

Answer 3

You are refering to check constraint
create table STAFF
(StaffID TINYINT IDENTITY NOT NULL,
fName varchar(20) NOT NULL,
lname varchar(20) NOT NULL,
Phone varchar(10) NOT NULL,
Gender char(01) NOT NULL,
DoB date NOT NULL,
Mentor TINYINT,
Payment_ID TINYINT NOT NULL,
constraint staff_pk primary key (StaffID),
constraint staff_fk foreign key (Payment_ID) references PAYMENT(Payment_ID),
constraint mentor_fk foreign key (Mentor) references staff(StaffID),
constraint Gender_ck check (Gender in ('M','F','O'))
)
"WITH CHECK OPTION" is an optional clause for of a view definition
Any attempt to update/insert a record, through the view, that cannot be selected by the view, will raise an error.