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Database Essential KU Q's

Terms in this set (14)

Describe primary key (2)
Answer: A primary key uniquely (1) identifies a record in a table (1)
Describe foreign key (2)
Answer: A foreign key links two tables (1). The foreign key of one table is the primary key of the parent table (1)
What act must businesses comply with when storing personal data (1)
Answer: General Data Protection Regulation (GDPR)
State 6 implications of this act that businesses must comply with (6)
Answer:
data must be:
•Processed lawfully, fairly, and in a transparent manner in relation to individuals (1)
•Used for the declared purpose only (1)
•Limited to data need for the declared purpose (1)
•Accurate (1)
•Not kept longer than necessary (1)
•Held securely (1)
State the 6 attribute types (6)
Answer:
•Text (1)
•Number (1)
•Date (1)
•Time (1)
•Boolean (1)
•Graphic (1)
How can databases be designed? (2)
Answer:
•ER diagrams (1)
•Data dictionary (1)
Describe the 4 types of validation (8)
Answer:
•Presence check (1) - sets the field to required so the user cannot leave it blank. Primary key fields must have a presence check (1)
•Restricted choice (1) - restricts the user to enter the only acceptable options, eliminating input error (1)
•Field length (1) - checks that the input meets a certain maximum and/or minimum length (1)
•Range (1) - ensures data input is only between a certain range/limit (e.g. > 0 and < 100) (1)
Explain an advantage of using a relational database over a flat file database (2)
Answer: As flat file databases could have thousands of unorganised records in the one table, which can produce insertion problems such as data duplication, modification errors, relational databases allow the data to be split into more manageable and organised tables, ensuring that data is not duplicated, by reducing human error, and modification problems
1 mark for explanation of flat file DB problems, 1 mark for explanation of how these problems are rectified using relational DB
Explain referential integrity (1)
Answer: When a foreign key value is used, it must reference a valid, existing primary key in the parent table
What logical operators are used for complex SQL queries? (2)
Answer:
•AND (1)
•OR (1)
What field type should a field containing images have? (1)
Graphic
How can results be ordered? (2)
Answer:
•Ascending order (1)
•Descending order (1)
How can we test queries? (1)
Answer:
Compare the expected results with the actual results
How are primary and foreign keys denoted on an ER diagram? (2)
Answer:
•Primary key - underlined (1)
•Foreign key - Asterix * (1)
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