G51DBS 2009-2010 Coursework 2

Worth 5% of the total mark.
Deadline: I would prefer to mark it in the lab on the 16th or the 23rd (please also submit your coursework to cw system, id 263, even if you had it marked in the lab - for the record). You can submit to cw without any points deducted until Friday the 26th of February, 23:59. After that you can still submit until the 5th of March at 23:59 but I will subtract points for lateness.

General instructions

Make sure you have an Oracle account

Please make sure you can use Oracle first. Instructions are in Getting started with Oracle.

Run SQL from a file

It is possible to create the same database and insert the tuples interactively, and you are welcome to practice this way, but for the exercise please place all your SQL statements in a file. Call it cw2.sql, save it in the directory from which you start sqlplus, and run the statements by typing start cw2.sql; at the sqlplus prompt.
We will ask to see your file in the lab when we are marking the exercise. Please also submit it to cw, coursework id is 263.
The comment character in SQL is --. For example files, look at last year's exercise solutions here.


Create a file containing SQL statements which will create tables described below and populate them with specified tuples. Run statements from the file to create a database instance.



Insert data about the two books above in the database. Use a sequence to generate personIDs. [Comment: a better solution would be to use something like JeffreyDUllman1, JeffreyDUllman2 etc. for IDs and generate them by hand or using a program which checks for the person's affiliation, research area and so on to decide if it is the same person or a new author with the same name. But I would like you to practice using sequences.]. To avoid looking up generated IDs when inserting tuples into Author you can use
INSERT INTO Author VALUES ('0-13-861337-0', (SELECT PersonID FROM Person WHERE LastName = 'Ullman'));
which is generally not a good idea, but works in our example because last names happen to be unique (they will not be in general of course).

How to fix mistakes

If you make a mistake and want to remove a table called Sometable (together with all its contents), type DROP TABLE Sometable; at the sqlplus prompt.

If you want to remove or change a tuple, use DELETE FROM Sometable WHERE ... or UPDATE Sometable SET ... WHERE ...

How to check the result

To see the result, type SELECT table_name FROM user_tables;
This will give you a list of all the tables you have made. If you want to see the details for a table called Sometable, type

DESCRIBE Sometable;
This will list the column names, data types, and whether NULLs are allowed for Sometable.

If you want to see which tuples are in Sometable, type

SELECT * FROM Sometable;
This will list all the rows in Sometable.

We will use these commands to mark the exercise. Here is the model output. Note that to make Book display nicer I included at the end of the file formatting instructions for columns in my cw2.sql solution:
COLUMN Publisher FORMAT A15;
This wraps up the text in the Title column to 30 alphanumerical characters.

Marking scheme

You get full marks (5/5) if your output is similar to the model output (ID values could be different) and keys are declared properly. To check whether you defined primary keys correctly try, for example, adding a new book with the same isbn number as some book already in the database, and a different title (should not succeed). To check whether you defined foreign keys properly, try to delete the whole table Book - this should be impossible since books are referenced by the Author table.
Mistakes such as not declaring constraints properly will be penalised by 1 or 2 marks.