WorksheetsDatabase Normalization 1NF-3NF
Total questions: 25
Worksheet time: 13mins
Normalisation is:
Removing all necessary data from a database
Organising a database to remove repeated entries and increase the accuracy of the data
Putting fields from different tables into one big database
Which of the following statements fully describes data in 2NF:
When any repeating fields have been removed and the table is given a primary key
When all repeating entries of data are removed and the fields in each table are directly related to the primary key and no fields are present that are not related to each other
When all the fields in each table are directly related to the primary key
A disadvantage of normalisation is:
The data loses its integrity as some of it is removed in the normalisation process
The process of searching the database may be slower due to a higher demand on the central processing unit (CPU)
Removing redundant data means that links cannot be created between tables
A relation is in 1NF if it doesn't contain any ____________?
Determinants
Repeating groups
Null values in primary key fields
Functional dependencies
A table is in 2NF if the table is in 1NF and what other condition is met?
There are no functional dependencies.
There are no null values in primary key fields.
There are no repeating groups.
There are no attributes that are not functionally dependent on the relation's primary key.
When you normalize a relation by breaking it into two smaller relations, what must you do to maintain data integrity?
Remove any functional dependencies from both relations
Assign both relations the same primary key field(s)
Create a primary key(s) for the new relation
A ____ key is an artificial PK introduced by the designer with the purpose of simplifying the assignment of primary keys to tables.
surrogate
composite
candidate
foreign
Tables in ____ will perform suitably in business transactional databases.
0NF
1NF
2NF
3NF
A table where all attributes are dependent on the primary key and are independent of each other, and no row contains two or more multivalued facts about an entity, is said to be in ____.
1NF
2NF
3NF
4NF
A table in ____ contains no transitive dependencies.
1NF
2NF
3NF
none of the above
When is a table is said to be 3NF
Normalization improves performance by reducing redundancy.
If and only if it is in 2NF and every non key attribute is Non-transitively dependent on the primary key
It involves introduction of redundancy in data
None of the above
Which of the following statements fully describes data in 2NF:
When any repeating fields have been removed and the table is given a primary key
When all repeating entries of data are removed and the fields in each table are directly related to the primary key and no fields are present that are not related to each other
When all the fields in each table are directly related to the primary key
What is a foreign key?
A unique identifier in a database
A primary key of one table that appears in another table
A field that should not be in a table and needs removing
The ____ model views the data as part of a table or collection of tables in which all key values must be identified.
relational
object-oriented
conceptual
external
Identification of the ____ will let you know where you are in the normalization process.
normal form
primary key
attributes
repeating groups
An advantage of normalisation is:
The storage space needed for a normalised database is likely to be smaller
The process of normalising a database is very easy and doesn’t require any skill
It is possible to see previous details that have been changed, such as a customer’s address, as we can look back at an older entry
What is an atomic field?
A field that contains multiple items of data
A field that is repeated
A field that contains only one item of data
