DBMS Gate Quiz

Which one of the options given below refers to the degree (or arity) of relation in relational database systems? [GATE CSE 2023]

• 1. Number of attributes of its relation schema.

• 1. PersonNumber of tuples stored in the relation.

• 1. Number of entries in the relation.

• 1. Number of distinct domains of its relation schema.

In a relational data model, which one of the following statements is TRUE? [GATE CSE 2022]

• A relation with only two attributes is always in BCNF.

• If all attributes of a relation are prime attributes, then the relation is in BCNF.

• Every relation has at least one non-prime attribute.

• BCNF decompositions preserve functional dependencies.

Which one of the following is used to represent the supporting many-one relationships of a weak entity set in an entity-relationship diagram? [GATE CSE 2020]

• Diamonds with double/bold border

• Rectangles with double/bold border

• Ovals with double/bold border

• Ovals that contain underlined identifiers

A prime attribute of a relation scheme R is an attribute that appears [GATE CSE 2014]

• in all candidate keys of R.

• in some candidate keys of R.

• In a foreign key of R.

• only in the primary key of R.

Given the basic ER and relational models, which of the following is INCORRECT? [GATE CSE 2012]

• An attribute of an entity can have more than one value.

• An attribute of an entity can be composite.

• In a row of a relational table, an attribute can have more than one value.

• In a row of a relational table, an attribute can have exactly one value or a NULL value.