20 Questions
Relational algebra is a theory that uses algebraic structures for modeling data.
True
The main application of relational algebra is to provide a theoretical foundation for object-oriented databases.
False
Unary operators in relational algebra accept two relations as input.
False
Natural join is a unary operator.
False
The result of the Cartesian product is a set of (n+m)-tuples.
False
Projection is a binary operation.
False
The result of a selection operation is a relation that contains every attribute of every unique record.
True
True or false: The natural join is the relational counterpart of the logical OR operator.
False
Which type of query language takes instances of relations as input and yields instances of relations as output?
Relational algebra
Which operator in relational algebra is used to select tuples from a relation based on some condition?
Selection operator
What is the result of a projection operation in relational algebra?
A relation with only selected columns
Which operator in relational algebra is used to join two relations?
Cartesian product
What is the purpose of the rename operation in relational algebra?
To rename the output relation
Which operator in relational algebra gives a relation with tuples that are in the first relation but not in the second relation?
Set difference
Which operator in relational algebra is used to filter certain attributes or tuples from an input relation?
Selection
Which of the following is a requirement for the Cartesian product to be defined?
The two relations involved must have disjoint headers
What does the natural join operator in relational algebra do?
Combines tuples from two relations based on their common attribute names
Which of the following statements is true about the left outer join operator in relational algebra?
The left outer join operator returns tuples that have no matching tuples in the left relation.
What is the main purpose of the theta-join operator?
To combine tuples from two relations based on a condition that is not simply the equality of shared attributes
What is the division operation in relational algebra?
The division operation is the result of restricting tuples in one relation to the attribute names unique to that relation.
Test your knowledge of relational algebra and its applications in database theory with this quiz. Explore the theory introduced by Edgar F. Codd and its usage in relational databases and SQL query languages.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
