Choose the correct statements in the context of DBMS. A. DBMS is a software to…

Concept: A database management system (DBMS) is the software layer through which databases are created, stored, queried and administered, and a schema is the design-time description of such a database — its relations, attributes, data types and constraints. Inside the relational model the two key constructs have opposite jobs: a primary key is the attribute (or attribute set) whose value uniquely identifies each tuple of its own relation, while a foreign key is an attribute of one relation that must draw its values from the primary key of another relation, and is therefore the construct that links two relations. SQL is the standard declarative language in which relational data is defined and queried.

Application to the given statements:

1. Statement A restates the definition of a DBMS as software for creating and managing databases, which is exactly what the term denotes.

2. Statement B restates the definition of a schema as the design of the database, which is exactly what a schema records.

3. Statement C gives unique identification to the foreign key. Unique identification of a tuple within its own relation is the primary key’s job, so this statement puts the primary key’s role on the foreign key.

4. Statement D gives the linking of two relations to the primary key. Linking is achieved when a foreign key in one relation references another relation’s primary key, so this statement puts the foreign key’s role on the primary key. Statements C and D are the two halves of the same swap.

5. Statement E gives the standard expansion of SQL, Structured Query Language, which is the accepted full form.

Cross-check — primary key versus foreign key:

Result: the statements that hold are A, B and E, so the correct selection is “A, B and E only”. The remaining two statements are wrong only because the roles of the primary key and the foreign key have been interchanged; correcting the swap makes both of them true.