Database - Departamental Exam Practice

Components of Relational Model?

Components of Relational Model?

Data Structure, Data Manipulation, Data Integrity

Data structure Components?

Tables ( relations ), Rows ( records ) and Columns ( attributes )

Definition of Data Manipulation?

Powerful SQL operation for retrieving and modifying data

SQL Definition?

Structured Query Language

Definition of Data Integrity?

Mechanism for implementing business rules

Definition of Relation?

Two-dimensional table of data

A table consists of?

Table Rows and Columns

An attribute that uniquely identifies each row in a relation

Primary Key

This type of primary key consists of two or more attributes

Composite key

An attribute in a relation that serves as the primary key of another relation in the same database.

Foreign Key

Key fields can be ______ or ________

Simple ( single field ) or Composite ( more than one field )

Identifiers that enables a dependent relation

Foreign Keys

The order of the rows and columns must be?

Irrelevant

Five requirements for a table to qualify as a relation?

1. Must have unique name

2. Every attribute value must be atomic

3. Every row must be unique

4. Attributes must have unique names

5. The order of the columns must be irrelevant

_______, in which each relation is represented by a rectangle containing the attributes for the relation

Graphical Representation

Can a relational database may consists of any number of relations?

Yes

Two common methods for expressing a schema?

Short text statements and Graphical Representation

______, in which each relation is named and the names of its attributes follow in parentheses

Short text statements

Define Short Text Statement

Each relation is named and the names of its attributes follow in parentheses

Define Graphical Representation

Each relation is represented by a rectangle containing the attributes for the relation

Define Referential Integrity

The rule states that any foreign key value MUST match a primary key value in the relation of the one side

Define Restrict

Does not allow deletion of the parent table if other rows depends on it

Relation is a term for?

Tables

Relations correspond with?

Entity type and many to many relationship types

Rows correspond with?

Entity instances and with many-to-many relationship instances

Columns correspond with?

Attributes

Is the word relation (in relational database) the same as the word relationship (in E-R model)?

No

Define Domain Constraint

Allowable values for an attribute

What is Entity Integrity?

Primary key should never be null

What is Action Assertions?

Business rules

Delete Rule that don’t allow delete of “parent” side if related rows exist in “dependent” side?

Restrict

Delete Rule that automatically delete “dependent” side rows that correspond with the “parent” side row to be deleted

Cascade

Delete Rule that set the foreign key in the dependent side to null if deleting from the parent side not allowed for weak entities

Set-to-Null

Three types of Entity?

Regular Entities, Weak Entities, Associative Entities

Define Relational Schema

A visual depiction of the relational database model

Entities that have an independent existence and generally represent real-world objects, such as persons and products.

Regular Entities

______ are entities that cannot exist except with an identifying relationship with an owner (regular) entity type.

Weak Entities

_______ are formed from many-to-many relationships between other entity types.

Associative entities

Rows correspond with?

entity instances and with many-to-many relationship instances.

Columns correspond with?

Attributes

Allowable values for an attribute.

Domain Constraints

_____ implements 1:N relationship

Foreign Key

Define Unary Relationship

A relationship between the instances of a single entity type.

Integrate all the functions such as the manufacturing, finance, sales, marketing, inventory, accounting, human resources.

ERP

The type of database applications that can be use by more than 100 users and this uses distributed server.

enterprise

A detailed representation of data and their relationships.

Project data model

It is a stored representation of objects and events that have meaning and importance in the user’s environment.

data

In database approach, data is manage by an IT director

False

The data processed to increase knowledge in the person using the data

information

This refers to data about data.

metadata

ERP stands for ___________________________

Enterprise Resource Planning

The type of database applications that can be use by five to twenty five users.

workgroup

Integrated decision support system derived from various operational databases

Data warehouse

A software system that is used to create, maintain, and provide controlled access to user databases.

DBMS

Data redundancy comprises

data integrity

EDI stands for ____________________

Electronic data interchange

The graphical system showing the definition and relationship of data.

Data model

A broad representation of data and their relationships.

Enterprise data model

In the conceptual data modeling under prototyping methodology what is the main objective?

to analyze the requirements and develop the data model.

Steps to Top-Down planning are

1. Planning

2. Analysis

3. Design

4. Implementation

This is the database schema that provides the E-R models.

cenceptual

This provide relationships between planning objects in the organization

Planning Matrixes

What are the phases in SDLC?

1. Planning

2. Analysis

3. Logical Design

4. Physical Design

5. Implementation

6. Maintenance

The iterative process breaking system description into finer and finer detail

functional decomposition

Prototyping can be described as?

for rapid development, Cursory attempt at conceptual data modeling

A generic Information system planning methodology for obtaining a broad understanding of the information system

Information Engineering

The main purpose of the 1st phase in the SDLC is to have_______________?

preliminary understanding of the system

Enterprise data model describes the high-level entities in an organization and the relationship between relations

False

In this schema, the database administrator determines the schema for different users.

External Schema

phases of Information Engineering planning?

1. Identify strategic planning factors

2. Identify corporate planning objects

3. Develop an enterprise model

User must enter a digit.

0

User can enter a digit, space, plus or minus sign.

#

User must enter a letter.

L

User can enter a letter or digit.

a

User must enter either a character or a space.

&

Converts all characters that follow to uppercase.

>

Characters immediately following will be displayed literally.

W

Causes the input mask to fill from left to right instead of from right to left.

!

Converts all characters that follow to lowercase.

<

User can enter a letter.

?

In Access, it is the custom screen that provide an easy way to enter and view data.

Form

Part of the Design view interface that allows you to define an object's appearance, behavior or characteristics.

Field Properties

Used to set a particular format for your field.

Input Mask

In Access that  allows you to set how the data in the field will be displayed on the screen.

Format

Highest value for field size of short text is

255

Stop the users from entering incorrect data into your tables.

Validation Rule

If the data to be filled-in is optional, the property ___________ must be with No value.

Required

Primary is a must in each table.

False

Relationship will be generated after the setting Lookup property of a field.

True

Short Text field size can be as low as 0. 

False

The Access object that is used to define and store data.

Table

The total quiz points for a student for an entire semester is a(n) ________ attribute.

derived

A fact is an association between two or more:

terms

An attribute that must have a value for every entity (or relationship) instance is a(n):

required attribute.

An attribute that can be calculated from related attribute values is called a(n) ________ attribute.

derived

In transforming ERD to relations, if there is a multivalued attribute, another relation will be created and the identifier of the superior entity will be also its identifier

False

In mapping binary relations, the Primary key on the one side becomes the foreign key on the many side when it is ___________.

1:M

In mapping binary relations, primary key on the mandatory side becomes the foreign key on optional side when it is_________.

1:1

When all multivalued attributes have been removed from a relation, it is said to be in:

first normal form

A primary key whose value is unique across all relations 

enterprise key