Final answer:
A composite identifier consists of multiple attributes that collectively ensure a unique identification of a record. The correct answer to the provided question is 'a) Composite', which is different from primary, unique, or foreign identifiers.
Step-by-step explanation:
A composite identifier is composed of more than one attribute. The correct answer to the student's question is: a) Composite.
Identifiers in the context of databases can be broadly categorized into several types - composite, primary, unique, and foreign identifiers. A primary identifier, or primary key, is a unique identifier for each record in a table, which can be a single attribute or a composite of multiple attributes. A unique identifier, or unique key, ensures that all values in a column, or a combination of columns, are different for all records. A foreign identifier, or foreign key, is an attribute that creates a link between two tables.
The use of a composite identifier often occurs when no single attribute uniquely identifies a record. In such cases, combining two or more attributes that together are unique for each record can serve as a composite key. For instance, in a college database, a composite key might consist of both the student ID and a course code to uniquely identify a student's enrollment in a particular class. Here, neither the student ID nor the course code alone is sufficient to distinguish each record - but together, they can.