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Introduction to
Databases
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1. Outline the key benefits of using databases. Computer Confluence, pp. 267268.
Databases make it possible to store large quantities of information. In fact,
databases are much more worthwhile software applications the greater the
volume of information there is to catalogue.
Databases make the search and retrieval of information both quick and easy.
There is also greater flexibility in searching and retrieving information that paper
directories or catalogues. This is because a database can accommodate a variety
of searches. Take for instance having written a phone number down and you wish
to trace the name of the person / company who’s name you have forgotten. Doing
this with a phone book could take hours. A database with phone numbers,
however, would allow you to search by name, address and number, saving huge
amounts of time with the flexibility of available searches. It is no wonder why the
White Pages now exists as an online database.
Databases make it easy to organise and re-organise information. Databases offer
the flexibility to switch between organisation schemes far more easily than a
paper filing system.
Databases allow for the easy distribution of information with its ability to sort
information and then combined with print features such as a mail merge, printing
of the information is quicker. For example, of all the donors to the RSPCA, the
organisation is throwing a charity event to which they wish to invite all their
largest donors. The database could sort the pick out all the donors that have given
x amount of money in the last 12 months and then do a mail merge to produce the
letters and addressed envelopes.
2. Define the following terms: 


Database – a collection of organised information stored on a
computer. For example this could be the details of patients at a doctors
surgery or student details at a local primary school.
Table – is like a spreadsheet in storing all the related information
together, much like a filing cabinet.
Field – is a category of information e.g. student id number, student
name, student address etc. Fields usually make up the columns of the
database.

Record – Is the information related to one person, product or event in
the database. For example, in the school each record is an individual
student.
Computer Confluence, pp. 268-269 and handout
3. Briefly describe the different types of fields (the different data types) that can
exist in a database. Computer Confluence, pp. 268-269.
Fields have a specific data type assigned to them for the purpose of entering
information into the database. For example, a numeric field only allows only
numerical values to be entered into the field. Another example is a date field,
which allows only date values. Computed fields allows formulas to be contained
within them to calculate a numerical value based on information from other fields
in the database. String fields allow for text only entry. Some fields can be
specified to hold graphics, sound, movies etc. Depending on the database being
used, fields are sometimes designed for the specific use in mind.
4. Describe the key operations that can be performed using a database including
browsing, querying, sorting, printing and complex queries. Computer
Confluence, pp.269-271 and handout
Browsing – looking over records in the database in a more general manner. For
example in the iTunes database you may browse by genre of music and look at the
artists who have been classified and linked to the particular genre of music being
browsed e.g. R&B.
Querying – is looking for specific information and then having that information
displayed. Again, using the iTunes database, you could look up a specific song,
album, podcast etc. You could be conducting a query to get one record or several.
With some databases you can save the queries, so that you do not have to write a new
query the next time. For example, Gold Effort awards at PAC are given to all students
who obtained all 1’s for effort. Rather than re-write this query each time the
information is needed, at the end of each term, the query can be saved as a stored
query and labelled e.g. students with gold awards Term 1 etc.
Sorting – allows the use to view the information in a particular way. For example,
when using the eBay database, you can sort the information by distance from your
home or by price. Many databases allow you to sort by information contained in one
or more fields.
Printing – of information can be carried out in a variety of ways by databases,
usually in easy to read tabular form, with summaries should they be required. For
example, the layout of school reports is defined using the database print option and
then the information is assigned to the appropriate areas of the layout. Many
databases allow the export of information to other packages for printing. This
happens with mail merge and sometimes data that you wish to use in a spreadsheet to
produce graphs etc.
Complex Queries – are those queries that want to find very specific information from
a variety of fields. These are often conducted using Boolean logic (AND, OR, NOT,
<, >, EQUAL). Most programs allow the user to specific the search through the use
of a dialogue box or blank on-screen form. This language of instructing the computer
to retrieve complex information from the database is known a query language.
5. Define Structured Query Language and briefly explain its purpose. Computer
Confluence, pp. 271 and 274-275.
As database operators move from job to job, it is important that they do not have to
learn the new query language that expresses the logic commands slightly differently
from what they are used to. As a result, many databases use the same standard
language known as Structured Query Language (SQL). In many databases today,
rather than writing the query logic there are point and click commands to make
things easier.
6. Explain what is meant by a Database Management System (DBMS). Give
some examples of groups or organizations that would use one and why.
Computer Confluence, pp. 277-279 and handout.
A database program or system that can manipulate data in a large collection of filesthe database-cross-referencing between files as needed. This overcomes the problem
of trying to store all the information on one table. A DBMS can use several tables,
each of which is set up for a specific aspect of the organisation. This type of database
is known as a relational database.
7. In a DBMS what is meant by the key field. Computer Confluence, pp. 279.
By using a key field, which is a field that is shared by all the tables in the database,
information is not having to be updated in each of the tables, which improves data
integrity.
For example, a College database may have a three tables: 1. Student details (student name, student number, parents, address etc)
2. School Fees information
3. School Grades
The key fields for this database would be the student names and number, being shared
by all three tables. If the student left the school it would only need to be recorded in
one place (student details).
8. Differentiate between a flat file database and a relational database. See
handout.
A flat file databases keep information in a single table. This means if you had two flat
file databases both with address fields for the same clients. You would have to
duplicate you work in updating the information, which is time consuming and if not
done properly, will lead to a loss of data integrity. Because information has to be
entered in both files increased probability of data entry error arises. There still is the
same functionality in terms of browsing, querying, sorting and printing.
A relational database incorporates multiple tables with methods for the tables to work
together. This means that information from different tables in the database can be
merged, collated and displayed. Relational databases use key fields to identify crucial
information critical to the understanding of each table.