Consider following two statements: Statement I: Relational database schema…
2021
Consider following two statements:
Statement I: Relational database schema represents the logical design of the database.
Statement II: Current snapshot of a relation only provides the degree of the relation.
In the context to the above statements, choose the correct option from the options given below:
- A.
Statement I is TRUE but Statement II is FALSE
- B.
Statement I is FALSE but Statement II is TRUE
- C.
Both Statement I and Statement II are FALSE
- D.
Both Statement I and Statement II are TRUE
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Correct answer: A
Answer: Statement I is true and Statement II is false.
Statement I: A relational database schema represents the logical design of the database. This is correct because the schema defines the relations, attributes (columns), and constraints independent of the actual data stored.
Statement II: A current snapshot of a relation only provides the degree of the relation. This is false. A current snapshot (instance) of a relation lists the tuples (rows) that currently exist, so it conveys the cardinality (number of tuples) and the actual data values. The degree (number of attributes) is a property of the schema, not something that the snapshot "only" provides.
Key point 1: Schema (logical design) defines degree (arity) and attribute names.
Key point 2: An instance (current snapshot) shows tuples and provides cardinality (number of tuples) and actual data values.
Therefore, the correct conclusion is that the relational schema represents the logical design (true), and it is incorrect to say that a current snapshot only provides the degree (false).
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