G51DBS 2007-2008 Coursework 2

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 when we are marking the exercise.
The comment character in SQL is --. For example files, look at the 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 your own timetable this semester (for the modules you are taking this semester, usually it is 6 modules), using the university room names. For example, LT2 is JC-EXCHGE-C.LT2, for Location you can put Exchange or Central Teaching Facility. The timetable is available here . Activity is supposed to represent a lecture or a lab session for a particular module. For example, for the G51DBS lecture on Monday use actModCode G51DBS and actDescription Lecture1. For G51PRG lab use actModCode G51PRG and actDescription Lab. In Schedule, use strings like Mon 9-10 for slots.

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 for just G51DBS and G51PRG assuming PRG labs are 14:00-16:00. To make the column names actModName and actDescription display in full, you can add

COLUMN actDescription FORMAT A14;

to your file.

Marking scheme

You get full marks (5/5) if your output for DESCRIBE is as in the model output, rows in the tables are similar to the model output, and keys are declared properly. To check whether you defined primary keys correctly try, for example, adding a new room with the same name as some room already in the database, and a different location (should not succeed). To check whether you defined foreign keys properly, try to remove one of the rooms mentioned in the Schedule or drop the whole table Room - this should be impossible since rooms are referenced by Schedule.
Mistakes such as not declaring constraints properly will be penalised by 1 or 2 marks.