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Computer Science

GCSE · AQA

QuestionsFlashcards

Cyber Security Threats
Social Engineering
- What Social Engineering Is
  4
- Blagging, Phishing & Shouldering
  5
Malware
- What Malware Is
  2
- Viruses, Trojans & Spyware
  3
Detecting & Preventing Threats

Updating & Deleting Data Flashcards

All 4 cards in this deck

Which SQL command changes data in records that already exist?: UPDATE, with SET giving the new values and WHERE choosing the records:
UPDATE Pet SET Weight = 4.2 WHERE PetID = 7
Which SQL command removes records from a table?: DELETE FROM, with WHERE choosing the records to remove:
DELETE FROM Pet WHERE PetID = 7
What happens if an SQL UPDATE or DELETE command has no WHERE clause?: It acts on every record in the table: every record is changed, or every record is deleted.
In SQL UPDATE and DELETE commands, why is the primary key often used in the WHERE clause?: Its value is unique, so the condition picks out exactly one record. A condition on a non-unique field, such as a name, could change or delete other records too.