Database System

note!Answer: A) Number of tuples.
Cardinality of a relation is the number of tuples (rows). Degree is the number of attributes.

note!Answer: B) Non- Procedural language.
Relational calculus is a non-procedural language: it states what to retrieve, not how.

note!Answer: A) Conceptual view.
The conceptual view describes the entire database content at the logical level.

note!Answer: B) a Binary operator.
The Cartesian product combines tuples from two relations, so it is a binary operator.

note!Answer: C) Manipulation & processing of database.
DML (Data Manipulation Language) is used to retrieve, insert, update and delete data.

note!Answer: B) Rename operation.
In SQL, the AS clause gives an alias (rename) to a column or table.

note!Answer: D) Open Database Connectivity.
ODBC is Open Database Connectivity, a standard API for accessing databases.

note!Answer: C) three levels.
The ANSI-SPARC architecture has three levels: external, conceptual and internal.

note!Answer: C) Tables.
In a relational model, a relation is represented as a table.

note!Answer: C) DDL
The database schema is defined using DDL (Data Definition Language).

note!Answer: D) view level.
The external level is also called the view level; it describes user views of the data.

note!Answer: B) weak entity set.
A weak entity set lacks sufficient attributes to form a primary key and depends on a strong entity set.

note!Answer: D) Tree.
The hierarchical model organizes records in a tree structure with parent-child relationships.

note!Answer: C) ellipse.
In E-R diagrams, entities are rectangles, and attributes are ellipses.

note!Answer: A) not Null
Entity integrity requires that the primary key cannot be NULL.

note!Answer: A) DML
DML is the language application programs use to request and manipulate data from the DBMS.

note!Answer: B) is a standard way of organizing information into accessible parts.
A logical schema is the logical organization of data; the physical schema describes storage on disk.

note!Answer: B) data record.
Related fields make up a record, and related records make up a file.

note!Answer: B) separate files.
A database environment replaces separate files with one integrated database, so separate files are not a component.

note!Answer: B) SQL.
SQL (Structured Query Language) is the standard language for interacting with relational databases.