13.2 - File Organisation and Access

Question 1

What is serial file organisation

Answer 1

• Method of file organisation
• Records are physically stored in a file
• One after another in the order they arrive

Question 2

What is sequential file organisation

Answer 2

• Method of file organization
• Records are physically stored in a file
• In a giver order based on the key field

Question 3

What is random file organisation

Answer 3

• Method of file organisation
• Records are physically stored in a file
• In any available position
• The position is found by applying a hashing algorithms to the key field

Question 4

What is sequential access

Answer 4

• Recordsa re searched one after another
• From the physical start of the file
• Untill record is found or end of file
• Used for serial and sequential file organisation

Question 5

What is direct access

Answer 5

• Records are found without reading other records
• For sequential, an index of key field in kept, and used to look up the address of required file
• For random, a hashing algorithm is usd on the key field to find the address

Question 6

What is open hashing

Answer 6

• When collision is detected
• File is searched linearly from the point of collision
• Record is stored in the next free space

Question 7

What is closed hashing

Answer 7

• An overflow array is setup beforehand
• When collision is detected
• Overflow array is searched linearly from the start
• Record is stored in the first avaialble space