Beginning SQL

Chapter 4
148
UPDATE Films
SET FilmId = 13
WHERE FilmId = 12 AND
FilmName = ‘The Good, the Bad, and the Facially Challenged’;
UPDATE Films
SET FilmId = 14
WHERE FilmId = 2 AND
FilmName = ‘15th Late Afternoon’;
UPDATE Films
SET FilmId = 15
WHERE FilmId = 2 AND
FilmName = ‘Soylent Yellow’;
Execute the following SQL to create the PRIMARY KEY constraint:
ALTER TABLE Films
ADD CONSTRAINT films_pk PRIMARY KEY (FilmId);
Next, add a PRIMARY KEY constraint to the Category table. The steps are identical to those described
previously. First, add a NOT NULL constraint. If you’re using MS Access or SQL Server, the code is as
follows:
ALTER TABLE Category
ALTER COLUMN CategoryId int NOT NULL;
If you’re using MySQL or Oracle, use the following statement:
ALTER TABLE Category
MODIFY CategoryId int NOT NULL;
Once again, with IBM’s DB2, you need to re-create the table:
CREATE TABLE TempCategory
(
CategoryId integer,
Category varchar(100)
);
INSERT INTO TempCategory
SELECT * FROM Category;
DROP TABLE Category;
CREATE TABLE Category
(
CategoryId integer NOT NULL,
Category varchar(100)
);
INSERT INTO Category
SELECT * FROM TempCategory;
DROP TABLE TempCategory;