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Ch 5 Exam Questions
Karten in diesem Stapel (8)
- 1State three characteristics of first normal form. [3]Data is atomic
No repeating field names
Primary Key - 2Draw the entity relationship diagram making sure that the degree of each relationship is identified. CUSTOMER, TILL, ORDER, SALESPERSON, ORDER_LINES [6]CUSTOMER-ORDER-SALESPERSON
TILL-ORDER_LINES-ORDER
Customer - Order = 1:M
Salesperson-Order = 1:M
Order-Order_Lines=1:M
Till-Order_Lines=1:M - 3Identify two characteristics of data in second normal form. [2]Data is in first normal form
All non-key attributes are dependent on the entire primary key - 4Describe three components of a data dictionary. [6]Table name; The name of the table unique for each table in the database
Field name; The unique name for each field
Data type; The data type allocated to each field - 5The database contains tables, records and fields. Describe how these database elements are related to each other. [3]Tables contain rows, and each row is a record. Tables contain columns and each column contains field headings and fields. Each record contains individual items of data.
- 6Explain the purpose of relationships in a database. [3]To link tables. To ensure referential integrity, which makes sure data is not duplicated. This reduces storage space required.
- 7Describe two disadvantages of normalisation. [4]Limits data storage, as calculated fields need to be stored.
Increases the number of tables, which increases memory requirements. - 8What is the difference between a simple and a complex query? [2]Simple contains one criteria. Complex contains more than one criteria linked with AND, OR and NOT.
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- A2 ICT AS (Ch 5 - Relational database concepts) Karteikarten am Ch 5 Exam Questions, erstellt von royc001 am 13/04/2013.
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