Database System

note!Answer: D) Diamond
In E-R diagrams, relationship types are drawn as diamonds, entities as rectangles, and attributes as ellipses.

note!Answer: A) Tree structure
The hierarchical model organizes data in a tree structure, with parent-child nodes.

note!Answer: C) ALTER
ALTER TABLE with DROP COLUMN removes a column from a table's structure. DROP removes the whole table, and DELETE removes rows.

note!Answer: C) IN
The IN operator checks whether a value matches any value in a specified list of literals. BETWEEN checks a range.

note!Answer: A) m
By definition, a B-tree of order m has at most m children per node. Each node can therefore hold at most m-1 keys.

note!Answer: B) MOD
MOD returns the remainder after dividing one number by another. For example, MOD(10,3) returns 1.

note!Answer: C) JOIN
JOIN combines records from two or more tables based on a related column. SELECT, PROJECT and PRODUCT do not combine records in this way.

note!Answer: D) Triangle
In an E-R diagram, generalization (and specialization) is shown as a triangle connecting the superclass to its subclasses. Entities are rectangles and attributes are ellipses.

note!Answer: A) View
A view is a virtual table defined by a SELECT query. It stores no data of its own and shows the result of that query.

note!Answer: B) Self Join
A self join joins a table to itself, usually using table aliases. It is used to compare rows within the same table.

note!Answer: A) RAW
In Oracle, the RAW data type stores binary or unstructured data. CHAR, NUMERIC and VARCHAR store character or numeric data.

note!Answer: B) Database Administrator
DBA stands for Database Administrator, the person who manages a database system.

note!Answer: D) Object Relational Database Management System
ORDBMS stands for Object Relational Database Management System.

note!Answer: A) Unbound
A control that is not linked to a table field is called unbound.

note!Answer: B) Open Database Connectivity
ODBC (Open Database Connectivity) is a standard API for accessing data across database programs.

note!Answer: A) Data dictionary
A data dictionary is a collection of data elements and their types and definitions.

note!Answer: B) Referential integrity
Referential integrity keeps relationships between tables valid when records are added or deleted.

note!Answer: A) Database
A database is an organised collection of related information about a particular subject.

note!Answer: A) 64 character including space
In MS Access, a field name can be up to 64 characters long, including spaces.

note!Answer: B) 64 character
MS Access allows field names up to 64 characters.