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Databases - Speaking Test 1 – Grade A
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Describe a database, explain use of data handling to create, maintain and interrogate database
Describe how + benefits of DBMS separation of data from applications
Describe principal features of DBMS to create custom applications
Relational databases – entities, tables, components of database – tables, forms, queries, reports and modules.
Use of logical operators
Key fields to connect tables and avoid data redundancy
Be able to describe validation of data as it is input
1. Define the term database.
A database is a persistent organised store of related data on a computer system.
2. What is a flat file database?
A flat file is a database in which all the data is stored in a single table.
3. What is a data model?
A data model is the way a database has been constructed.
4. What is a serial file?
It is a file of items one after another.
5. The words ‘one’, ‘two’, ‘three’, ‘four’, ‘five’, ‘six’ are saved one after another in a
data file. What type of file is this?
The file type is called a sequential file.
6. Explain how an indexed sequential file is searched to find a particular data item.
The software looks up the position of the item in the index, goes straight to the part
of the file where the required data is, then does a search there.
7. What is a field?
A characteristic of something stored in a database
8. What is a record?
All data about one item in a database.
9. What is an entity?
An entity is any item that has its attributes stored as data. An entity could be
anything, e.g. a book, a person, a film, a country or a football team.
10. What is an attribute?
An attribute is a characteristic of an entity. It becomes a field in a data table.
11. What is a one to many relationship?
It is a relationship where one record in a table may have links to many records in
another table.
12. What is an entity relationship diagram?
It is a diagram that shows how different entities used in a database are connected.
13. State what the initials DBMS stand for:
 Database Management System
14. Describe the features of a DBMS that can be used to create customised data
handling applications and explain why using a DBMS is desirable.
Features:
 Tools for creating the database structure e.g. creating tables, relationships,
queries
 Provides application and data independence
 Can create forms to manage data input and data validation
 Can create queries to select certain data and reports to display it in a meaningful
way
 Tools to control access to the data – access rights and security
Why desirable:
 The application provides a tailored view of the data for the user
 User doesn’t have to be an expert in using databases
 Separating application and data means the data can be accessed separately by
different applications for different people e.g. accounts department and sales
staff will use it differently
 Security protects the data – only gives access to people who need it
15. What is ACID?
A set of rules that protects a database from errors during a transaction
A: Atomicity
 A transaction is either completely carried out or not at all.
C: Consistency
 A transaction must take the database from one valid state to another. It must not
break any rules such as those of referential integrity.
I: Isolation
 No transaction may interfere with any other transaction. It should not be possible
for more than two transactions to be operating at the same time on one record
because the results could be unpredictable.
D: Durability
 Once a transaction has been committed, it must remain so, even in the case of an
error or power failure.
16. A grocery shop uses a database with a DBMS to keep records of its stock. The
database uses forms and reports. Describe each of these and give one example of
how it would be used in the shop’s database.
Forms:
 A screen used for data input and editing.
 User can use controls to enter data as well as type it in e.g. combo boxes and
check boxes.
 Data entered is saved to the database.
 The grocery shop may have a form to enter new products.
Reports:
 A snapshot in time of the data from a database for printing
 …formatted on a page in a way that makes it information.
 May be grouped or sorted and have totals
 The grocery shop may print a weekly sales report.
17. Define the term ‘data redundancy’.
Data redundancy is where data is needlessly repeated.
18. What key field is necessary to avoid data redundancy?
A primary key can be used to avoid data redundancy.
19. What is the primary key?
The primary key is the field that uniquely identifies each record in a table.
20. What is a table in a database?
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A table is a set of fields and records.
A table contains data about just one entity
Tables must have a primary key
Relational database tables are linked by primary and foreign keys
21. What is data integrity?
The integrity of the database relates to the data being valid, accurate and consistent.
22. What is the purpose of a query in a database?
Queries are used to search and filter a database. For example, when shopping online
you select the options that you need and run a search. You can also filter and sort
results, e.g. you may want the cheapest item first, or the item with the least time left at
auction. All these actions are searching, sorting and filtering – and they are all queries.
23. What is the purpose of a form in a database?
Forms are used to enter data into a database. This is only required if the database needs
a user to enter data. The form should make it clear what data should be inputted, e.g. if
you are selling something, you would fill in a form which prompts you for information like
product name, brand and size.
24. What is the purpose of a report in a database?
Reports are used to export data and present it in a way that is easy to read. For example,
your address book database is full of details such as addresses, emails, dates of birth,
but you might want to run a report to present just names and phone numbers.
25. What are modules in a database?
Database software and languages contain modules - pre-written programs. However,
when making a database you might think of actions you want to do that do not have a
specific module. In this case, you can edit modules in the programming language and
your own procedures.
26. Why is record locking used in multi-user databases?
Record locking is used to prevent conflicting updates when more than one user is
looking at a record.
27. Explain why a supermarket might make use of data mining?
To keep track how people shop, predict when people will shop, and how they’ll for
their items. For example many supermarkets use loyalty card to collect such data
about their customers.
28. What are logical operators used for?
Logical operators are a useful way of allowing more than one field at the same time
to be used to extract certain records in a database.
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The AND keyword lets the user to combine two fields. Both statements have to
be true in order to match a record. E.g., City = ‘London’ AND Surname = ‘Smith’.
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The OR operator allows for either part of a statement to be true in order to return
a record E.g., Surname = ‘Smith’ OR ‘Jones’
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NOT operator wants the condition to be false rather than true in order to return a
record. E.g., NOT (Surname = ‘Jones’)
29. Define the term ‘data validation’.
Validation checks that the correct type of data is entered. For example, validation
checks that a postcode has been entered in the correct format.
30. When a person joins a social networking website, they need to enter some personal
data which is validated using rules. For example, the date of birth must be in the
past.
State one rule that could be used when validating each of the following:
Email address
 Email address must contain an @ symbol
Gender
 Gender must be “Male” or “Female”
Password
 Password must be at least 6 characters long
31. Users can upload several pictures to their profile page on a social networking site.
Each picture has a date and a comment.
The personal data of users is stored in a table called USER. The data about the
pictures is stored in a separate table called PICTURE.
Explain why the data about the pictures should be in a separate table, and how the
tables can be linked.
 A user can upload more than one picture. If they were not in separate tables you
would have to store the user details for every picture – data redundancy.
 Separate tables mean no data redundancy as user details are just stored once per
user - no redundancy minimises data inconsistency.
 Tables are linked with a relationship between key fields – primary key in USER is
UserID and will also be the foreign key in PICTURE.
32. Explain why a supermarket might make use of data mining?
To keep track how people shop, predict when people will shop, and how they’ll for
their items. For example many supermarkets use loyalty card to collect such data
about their customers.