Oracle
1Z0-071 · Question #320
Which three statements are true about defining relations between tables in a relational database? (Choose three.)
The correct answer is A. Primary key columns allow null values. D. Every foreign key value must refer to a matching primary or unique key value. See the full explanation below for the reasoning.
Question
Which three statements are true about defining relations between tables in a relational database? (Choose three.)
Options
- APrimary key columns allow null values.
- BEvery primary or unique key value must refer to a matching foreign key value.
- CForeign key columns allow null values.
- DEvery foreign key value must refer to a matching primary or unique key value.
- EUnique key columns allow null values.
How the community answered
(50 responses)- A78% (39)
- B6% (3)
- C12% (6)
- E4% (2)
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