Entity Relationship Diagram Overview

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Questions and Answers

Which type of database model organizes data into a tree-like structure with a single parent for each record?

Hierarchical model (correct)

Relational model

Network model

Flat model

What type of participation allows one entity occurrence to exist without requiring a corresponding entity in a relationship?

Fully Required participation

Semi-Mandatory participation

Mandatory participation

Optional participation (correct)

Which of the following best describes Crow's Foot notation?

It is a complex notation for detailed system architecture.

It visualizes the cardinality and structure of relationships. (correct)

It focuses on the physical structure of data.

It is used mainly for documenting business processes.

What are the disadvantages of File Processing regarding data management?

Duplication of Data Signup and view all the answers

Which component corresponds with attributes in an Entity Relationship Diagram?

Columns in a table Signup and view all the answers

Which type of cardinality is NOT considered a basic cardinality in ERD?

N-to-N relationship Signup and view all the answers

Operational databases are also referred to as which of the following?

Transactional databases Signup and view all the answers

In Chen and Crow's Foot models, how is an entity represented?

As a square with its name Signup and view all the answers

Which type of key uniquely identifies each record in a database table?

Primary key Signup and view all the answers

What symbol is used to represent an attribute in an ERD?

Double oval shape Signup and view all the answers

Which of the following describes a derived attribute?

An attribute that is based on another attribute Signup and view all the answers

Which of the following accurately defines abstraction in data modeling?

Focusing only on data and its relationships Signup and view all the answers

What does ordinality describe in the context of entity relationships?

Whether a relationship is mandatory or optional Signup and view all the answers

Which of the following is NOT a challenge of database systems?

Decreased cost Signup and view all the answers

Which statement accurately reflects the problem associated with file processing systems?

Limited opportunities for adhoc queries Signup and view all the answers

What is the organized collection of logically related data called?

Database Signup and view all the answers

Which of the following statements about optional attributes is correct?

Optional attributes may be left empty. Signup and view all the answers

What is the purpose of metadata in a database?

To describe the characteristics and relationships of data. Signup and view all the answers

What happens to data consistency when a DBMS is implemented?

Data inconsistency is minimized. Signup and view all the answers

Which of the following describes the role of cardinality in Entity-Relationship Diagrams (ERD)?

It shows the number of occurrences of one entity associated with occurrences in another. Signup and view all the answers

What is a consequence of using a database approach with a shared data repository?

Improved data sharing and access. Signup and view all the answers

What does data redundancy refer to?

Unnecessarily storing the same data in multiple places Signup and view all the answers

In an Entity Relationship Diagram (ERD), which shape represents an Entity?

Rectangle Signup and view all the answers

Which of the following is NOT a function of a Database Management System?

Excessive Program Maintenance Signup and view all the answers

Which statement accurately describes data models?

They revolve around discovering and analyzing organizational and user’s data requirements Signup and view all the answers

What denotes processed data that increases knowledge for the user?

Information Signup and view all the answers

What is a characteristic of the Unified Modeling Language in database design?

It provides detailed conceptual models focusing on attributes and relationships Signup and view all the answers

What does Crow's foot notation use to represent an entity relationship?

Rhombus Signup and view all the answers

What is a cost and risk associated with the database approach?

Need for new and specialized personnel Signup and view all the answers

Which type of key is used to uniquely identify each record in a database table?

Primary Key Signup and view all the answers

Which of the following characteristics is NOT required for business rules?

Must be in verbal form Signup and view all the answers

What describes the mandatory or optional nature of a relationship in an Entity-Relationship Diagram?

Cardinality Signup and view all the answers

Which notation is best suited for modeling software systems with a broader scope than just data structure?

Unified Modeling Language Signup and view all the answers

Which role is primarily responsible for implementing security policies in data administration?

Database Security Officer Signup and view all the answers

Which of the following statements about operational databases is correct?

They support a company's day-to-day operations. Signup and view all the answers

What is a primary concern of file processing where all programs must maintain metadata for each file used?

Program-Data Dependence Signup and view all the answers

What type of database is specifically designed to manage and provide data used for tactical and strategic decisions?

Data Warehouse Signup and view all the answers

Study Notes

Entity Relationship Diagram (ERD)

ERDs use graphic representations to model database components.
ERDs are mapped to relational tables.
ERDs are used for practical, industry-standard database design focusing on the structure and cardinality of relationships.
There are two common notations for ERDs:
- Crow's foot notation
- Chen notation
Attributes in ERDs correspond to Tables in RDBMS.
Entities are represented by a square in both Chen and Crow's foot notation.
Relationships are represented by a diamond in Crow's foot notation.
Attributes are represented by an oval in both Chen and Crow's foot notation.
Identifiers are represented by an underline under the name of the attribute.
A double oval represents an attribute that is multi-valued.
A rectangle represents an Entity.

Data Modeling

Data modeling describes operations to create and enforce actions within an organization’s environment.
Data modeling is a repetitive process that promotes improvement for every revision made.
Data modeling involves discovering and analyzing organizational and user’s data requirements.
Important data is identified and maintained in data modeling.

Database Management System (DBMS)

DBMS are a collection of programs that manages the structure and control of access to data.
DBMS improves data sharing and access.
Functions of a DBMS include:
- Security Management
- Data transformation and presentation
The type of database to be used will depend on the number of users and the extent of use.

Relational Model

The relational model sorts data into tables, also known as relations, each of which consists of columns and rows.
It is the most common database model.
It is used to represent complex data relationships.

File Processing

File processing is a method of storing and managing data in individual files.
It is not as efficient as a database approach.
Disadvantages of file processing include:
- No centralized control of data.
- Duplication of data.
- Limited data sharing.
- Program-data dependence.
- Lengthy development times.
- Can not perform adhoc queries.

Database Approach

Using a database approach, there is a central repository of shared data.
Data inconsistency is minimized when a DBMS is implemented.
It reduces data redundancy.
Advantages of a database approach include:
- Improved data security.
- Improved data sharing.
- Better data integration.
Disadvantages of a database approach include:
- Increased cost.
- Management complexity.
- Dependence on vendors.
- The need for specialized personnel.

Business Rules

Business rules standardize company's view of data.
Business rules allow designers to understand the nature, role, and scope of data.
They are used to develop appropriate relationship participation rules and constraints.
They act as a communication tool between users and designers.
Business rules must be:
- Shared among authorized users.
- Updated.
- Comprehendible.
Sources of business rules include:
- Company managers.
- Written documentation.
- Direct interviews with non-users.
- Policy makers.

Database Modeling

Abstraction in data modeling means that non-data modeling aspects are not included in the diagram.
Data models are used to represent database structure and the format of data which is managed by the database management system.

Data and Information

Information is processed data to increase knowledge in the person using the data.
Data is stored representations of meaningful objects and events.

Database Career Opportunities

Database designer implements security policies for data administration.
Database administrator manages the overall database system.
Database analyst designs and develops database solutions.

Keys

Primary key uniquely identify each record in the table.
Foreign key refers to the primary key in another table.
Composite key is a primary key composed of more than one attribute.

Other Key Concepts

An entity is anything about which we store information (people, places, objects, events, etc.).
An attribute is a property or characteristic of an entity.
Cardinality describes the relationship between entities and the number of occurrences in one entity that are associated to the number of occurrences in another.
Ordinality describes whether a relationship between two entities is mandatory or optional.
A derived attribute refers to an attribute derived or based on another attribute.
Metadata provides a description of data characteristics and relationships in data.
Optional attributes don't have to be filled-up.

Data Warehouse

Data warehouses contain and manage huge volumes of information used for tactical and strategic decisions.
They are used for business intelligence and analytics.
Data warehouses are typically designed for querying and reporting.
They optimize data for analysis rather than for transaction processing.

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Description

This quiz covers the key aspects of Entity Relationship Diagrams (ERDs), focusing on their use in modeling database components and mapping to relational tables. It explores various notations like Crow's foot and Chen, as well as the representation of entities, attributes, and relationships in ERDs.