Give the terms for each of the following:
Collection of logically related records.
Relation (or Table)
DBMS creates a file that contains description about the data stored in the database.
Data Dictionary (or Metadata)
Attribute that can uniquely identify the tuples in a relation.
Primary Key
Special value that is stored when actual data value is unknown for an attribute.
NULL
An attribute which can uniquely identify tuples of the table but is not defined as primary key of the table.
Alternate Key (or Candidate Key)
Software that is used to create, manipulate and maintain a relational database.
RDBMS (Relational Database Management System)
Explanation
These are fundamental database terms from NCERT Class 12 Computer Science. (a) A relation is a collection of logically related records called tuples. (b) DBMS creates a data dictionary containing metadata about database structure. (c) Primary key is an attribute that uniquely identifies each tuple in a relation. (d) NULL represents unknown or non-applicable values. (e) Alternate keys are candidate keys not selected as primary key. (f) RDBMS is software for managing relational databases.