Database Systems

A compilation of all questions and answers from this topic. A few relavant images to help with visual learners.

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Explain what is meant by data mining and give an example of how the library staff
might use it. (3) (June 2011)
Many companies would now struggle to operate effec vely without
database technology. Explain what is meant by a rela onal Data mining is the analysis of a large amount of data in a data warehouse to
database. (2) (Jan 2012) provide new informa on.
Look at book lending habits of par cular branches (1) to determine future
A rela onal database is a large collec on of data items and links purchases (1)
between them, using primary and foreign keys
Explain what is meant by a primary key and a foreign key. (2) (June
A primary key is unique and used to iden fy a record/table. / and
other fields depend on it
Describe what is meant by a data warehouse and explain the advantages it might A foreign key is a field of one table which is also the primary key of
give the library service. (3) (June 2011) another table / used to establish rela onships/links between tables.
Data warehouse refers to large amounts of data which are stored together,
usually in a single loca on, for further processing (a huge database specifically
structured for informa on access and repor ng)
Allows the council to store informa on about every book.
Allows the council to see who has borrowed books and when
Explain what is meant by each of the following terms:
Data consistency (1) (Jan 2011)
Data consistency is the rela onship between the input data, the processed data
and the output data as well as other related data. If the system is working
Give three reasons why rela onal databases are more secure than the flat file properly the data will be correct at each stage and is said to be consistent.
approach. (3) (June 2011)
Data redundancy (1) (Jan 2011)
Hierarchy of passwords Passwords to see separate parts Is where you store an item of data more than once
Storage of data separate to programs
Access rights to parts of the program. Data integrity (1) (Jan 2011)
Data integrity ­ the correctness of the data. Truthful, Accuracy
Data independence
Using appropriate examples, describe the advantages of a rela onal database Data independence ­ the data and the applica ons/programs used to access it
approach over a flat file approach. (6) (Jan 2012) are independent/separate.
Hierarchy of passwords ­ limits users to various parts of the program. A recep onist
would only have access rights to basic pa ent details whilst a doctor would see all
informa on on the pa ent.
Access rights ­ to parts of the program only certain users can access and change data. Give two other suitable tables; you would expect to see in this
A nurse would see all the informa on on a pa ent but unable to alter the drug dose library loan system, Iden fying any primary or foreign keys (7)
details whilst a doctor could. (June 2011)
Redundancy ­ Data redundancy is where you store an item of data more than once. If
BOOK [BookNo, Title, Author, Genre, ISBN, etc]
data is changed in one it will need to be changed in the other. LOAN [LoanID, BorrowerID#, BookNo#, StartDate, Length, etc]


Mr A Gibson

This is an innovative way of presenting previous exam questions and the main points from the specification that a student needs to know in order to answer them. I recommend this as a resource in itself and also as a method idea.

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