Beginning SQL

Chapter 10
296
This statement gives you the following results shown in Figure 10-9.
Figure 10-9
Suppose you then edit a member’s birth date such that the date is before January 1, 1970:
UPDATE MemberBirthdayFiltered
SET DateOfBirth = 1 / 1 / 1969
WHERE MemberId = 1
The UPDATE query modifies the birthday to a date in 1969, but MemberBirthdayFiltered pulls only records
for members with birthdays after January 1, 1970. Therefore, the record no longer matches the criteria and
disappears from the records pulled in the view, and the record would disappear from the view.
SELECT *
FROM MemberBirthdayFiltered
Figure 10-10
While it would still be in the table, the result would be disconcerting to the user, to say the least.
Another problem associated with views is that you could potentially insert or delete records that you are
not supposed to edit. Assume that the membership is divided by state with different people assigned to
maintenance of member records according to state. Build a view for birthdays in Golden State:
CREATE VIEW MemberBirthdaysGoldenState
AS
SELECT MemberId, FirstName, LastName, DateOfBirth, Street, City, State,
ZipCode, Email, DateOfJoining
FROM MemberDetails
WHERE (State = ‘Golden State’)
Having created the view, you can now execute the following SELECT * statement:
SELECT *
FROM MemberBirthdaysGoldenState
Executing the statement provides the results shown in Figure 10-11.
Figure 10-11