An alternate key in database table is also called
Candidate key
A candidate key is a minimal set of attributes that uniquely identifies every tuple of a relation. A relation may have several candidate keys; one is chosen as the primary key and each remaining candidate key is called an alternate (or secondary) key.
An alternate key is therefore itself a candidate key: it is unique and minimal, but it was simply not selected as the primary key.
It cannot be the primary key, because by definition it is the candidate key that was not chosen.
A super key is any attribute set that identifies tuples uniquely, minimal or not; an alternate key is a super key, but the term super key is far wider and is not a synonym.
A foreign key is an attribute that refers to the primary key of another relation and need not be unique, so it is unrelated to the notion of alternate key.
Candidate key option is correct.
Similar Questions
The degree of a relation in database is
Which of the following best describes the structure of a relational database ?
Which one is correct w.r.t. RDBMS ?
Important Questions from Relational Model
Given the relational schema $R = (U,V,W, X, Y, Z)$ and the set of functional dependencies: $$\{U \rightarrow V, U \rightarrow W, WX \rightarrow Y, WX \rightarrow Z, V \rightarrow X\}$$ Which of the following functional dependencies can be derived from the above set?
- The ‘12 Rules for Relational Database’ were given by
- Which of the following statement(s) is/are FALSE in the context of Relational DBMS ?
I. Views in a database system are important because they help with access control by allowing users to see only a particular subset of the data in the database.
II. E-R diagrams are useful to logically model concepts.
III. An update anomaly is when it is not possible to store information unless some other, unrelated information is stored as well.
IV. SQL is a procedural language. - Let $R(A,B,C,D,E)$ be a relational schema with functional dependency set $F=\{A\rightarrow BC,\ CD\rightarrow E,\ E\rightarrow A\}$.
Which of the following statements is correct? Consider R (A,B,C,D,E) be relation with following dependencies:
C- >F, E- > A, EC- >D, A- >B. Which of the following is a key for R?
