Which join operation retains all tuples from the left relation regardless of whether there is a matching tuple in the right relation, filling unmatched right attributes with NULL?
A Left Outer Join preserves every tuple from the left-hand relation; if no matching tuple is found in the right relation, NULL values are substituted for the right relation's attributes.
Which relational algebra operation is best suited for expressing queries involving universal quantification, such as 'Find students who have taken ALL courses offered by the CS department'?
The Division operation (R ÷ S) is specifically used for queries requiring 'for all' or universal quantification criteria.
What is the primary difference between Relational Algebra and Relational Calculus?
Relational Algebra is procedural (specifies operations and sequence of evaluation), while Relational Calculus is declarative/non-procedural (describes what data to retrieve using first-order predicate logic). Thus, all statements (A), (B), and (C) are correct.
What does it mean for a query language to be 'Relationally Complete'?
A relational query language is said to be relationally complete if it can formulate any query that can be expressed in basic relational algebra or domain/tuple relational calculus.
Which of the following SQL statements belongs to the Data Definition Language (DDL)?
DDL statements include CREATE, ALTER, DROP, and TRUNCATE, which are used to define and modify the schema of database structures.