Fundementals of Databases Flashcards

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1
Q

What does a record in a database indicate?

A

a row

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2
Q

What does a field in a database indicate?

A

A column

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3
Q

What is a falt file database?

A

A single table that stores all of the data held within that database

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4
Q

What is an advantage of a flat file database?

A
  • Easy to setup
  • can be made in software that many people can access such as a spreadsheet (excel)
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5
Q

What are limitations to a flat file database?

A
  • ‘data duplication/redundancy’ - repeating data unnecessarily
  • due to data duplication, flat file databases require much more storage
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6
Q

What is a relational database?

A

A database that consists of a number of linked tables in which each record usually records about a particular entity

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7
Q

What does each linked table in a relational database NEED to have?

A

A primary key

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8
Q

What is the main benefit of a relational database?

A

data does not have to be duplicated - this means it requires less storage as well as reducing the risk of mistakes that can happen when repeatedly inputting data

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9
Q

Define a primary key

A

a field/combination of fields in a table which is unique and enables you to identify every record in that table

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10
Q

What are the 2 types of primary keys?

A
  1. Simple
  2. Compound/composite
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11
Q

Define a simple primary key:

A

made up of a single field only

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12
Q

Define a compound/composite primary key

A

combines more than 1 field to make a unique value

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13
Q

What is a foreign key?

A

used to link tables together and create a relationship - it is the field in one table that is used to link to the primary key in another table

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14
Q

What is an orphan record?

A

A record that is not linked to any table where it should be

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15
Q

What is normalisation?

A

a technique for designing relational database tables to minimise duplication of information and to therefore safeguard against certain types of logical/structural problems

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16
Q

In what 3 ways does normalisation help?

A

1 - organises data efficiently
2 - eliminates redundant data
3 - ensures that onlu related data is stored in a table

17
Q

Define an attribute

A

characteristics about entities for example, each entity usually has it’s own record/field which hold information about that entity’s attriutes.

18
Q

What are normal forms made for?

A

it describes different levels of efficiency when designing a database

19
Q

When us a database generally considered normalised?

A

When it reaches the third normal form (3NF)