2007-07-01 Shallow treatement - with mistakes

The book appears to be very shallow. But, so is the AS in ICT. The book is broken up into 35 chapters and is supposed to cover the AS syllabus (AQA). Each chapter is typically 4-6 pages and briefly describes a self-contained topic. I suppose each chapter could be easily covered in a single lesson, leaving plenty of time for practical work. The AS comprises 2 written exam papers and a coursework that corresponds to the 3 sections in the book. At the end of the chapter there are a few questions - many of them old exam questions, to test the students knowledge. To my way of thinking there is not enough activities to engage a student, and so would be a poor guide unless that student is lucky enough to have a good teacher.

I have for my detailed criticism, limited myself to those chapters that involve aspects of database.

Chapter 17. The chapter starts with an introduction to what a database is, how you can retrieve information from a computerized database and the difference between a database and a DBMS. I cannot fault this bit, other than to say it is very brief. The sections on flat files is done very badly. After all a relational database is a flat-file system. The author states the following "There are several drawbacks to holding anything except very simple data in a single file (page 92). It is my understanding that with Microsoft Access all of the tables, queries etc go into a single file by default. The only problem with this is that of a performance issue if you are going to create a multi-user database. The point the author is trying to make is that it is much better to put your data in several tables - not files. This is likely to confuse students, who if they only use this book won't know the difference between a table and a file. There is an example of a table in first normal form (ORDERTABLE). The problems of using this table are then discussed on the next page. Valid points such as the presence of redundant data, and the problems this will make if data is updated are made. The examples given are however, rather contrived and weak. Next, using multiple tables are discussed. On page 94 there is a poor design involving employees and Orders. The chapter ends with a discussion of the benefits of database systems. Finally, there are just two questions to test the students knowledge.

Chapter 18 - Relational database. The chapter starts by saying that data is stored in tables if the database is relational. This description is inadequate. This is followed by a section called putting data in tables - that uses two examples. There is really no adequate explanation how you arrive at these tables, other than to say that commonsense would indicate that there could be two tables, BOOK and BORROWER. If at this point some ER modelling had been taught, you could state that there is a many-many relationship between the two entities - assuming of course that any borrower can borrow more than one book and that each book can be borrowed by other people. Unfortunately there are no ER models until you go to section 3 (The coursework chapter). Here in chapter 33 - design - you will see an ER diagram, but no explanation of ER modelling or indeed any explanation as to how you arrive at such a design. Later on there is a section on how to create a table in MS ACCESS and at the end of the chapter another 2 questions.

Chapter 19 - Tables, Forms, Queries and Reports, would appear to be a brief description of how to put together the main components required for a working database. It is however far too brief. Nothing is explained properly. What you have are some pictures (screen dumps) of what you should get, but no detail on how to achieve these results. On page 22 I spotted a serious mistake. The picture shows the relationships as they would be displayed in Access. The relationship between tblLOAN and tblBOOK is a one-one relationship. It should be a one-many relationship. You have this situation because of the mess made of the design in the previous chapter. If you are going to have one-one relationships you might just as well incorporate the data into one table. There is one example of a query using the QBE interface. There is a picture of a form based on the query on page 106 - with no explanation of how to do it. Perhaps the author expects you to use an Access book to find out how to do this. At the end of the chapter there follows 4 basic questions that could be answered in a few sentences if you know how to answer them. However you won't find the answers anywhere in this chapter.

Chapter 33 - Design. It was my undestanding that design was a process that takes you from A to B in several stages. Instead here, a design is pulled out of thin air. No explanation of where it came from is give. There is a more detailed description of data-types, but even this is far too brief. It looks to me that this entire chapter is merely a rehash of the AQA requirements, with very little added for the benefit of students who need it. This chapter takes up 3 pages and covers virtually nothing.