Podcast
Questions and Answers
Which of the following is NOT listed as an advantage of the relational model?
Which of the following is NOT listed as an advantage of the relational model?
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What is a potential disadvantage of the relational model?
What is a potential disadvantage of the relational model?
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What does the relational model promote by using independent tables?
What does the relational model promote by using independent tables?
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How does the relational model improve conceptual simplicity?
How does the relational model improve conceptual simplicity?
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Which of the following is a benefit of using SQL for ad hoc queries in the relational model?
Which of the following is a benefit of using SQL for ad hoc queries in the relational model?
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Which of these is NOT a characteristic of sparse data?
Which of these is NOT a characteristic of sparse data?
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What is the primary function of Hadoop Distributed File System (HDFS)?
What is the primary function of Hadoop Distributed File System (HDFS)?
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Which of the following is NOT a characteristic of NoSQL databases?
Which of the following is NOT a characteristic of NoSQL databases?
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What is the main benefit of using MapReduce for data processing?
What is the main benefit of using MapReduce for data processing?
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What is the role of 'velocity' in the context of Big Data?
What is the role of 'velocity' in the context of Big Data?
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Which of the following scenarios is a good example of where sparse data would be found?
Which of the following scenarios is a good example of where sparse data would be found?
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Why are NoSQL databases well-suited for storing sparse data?
Why are NoSQL databases well-suited for storing sparse data?
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What is the primary difference between Hadoop and MapReduce?
What is the primary difference between Hadoop and MapReduce?
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Which of the following is NOT considered a disadvantage of the Object-Oriented Model?
Which of the following is NOT considered a disadvantage of the Object-Oriented Model?
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The Object-Oriented Model's emphasis on inheritance promotes data integrity by:
The Object-Oriented Model's emphasis on inheritance promotes data integrity by:
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What is a direct consequence of the Object-Oriented Model's slow development of standards?
What is a direct consequence of the Object-Oriented Model's slow development of standards?
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Which of the following issues directly stems from the complexity of the Object-Oriented Model?
Which of the following issues directly stems from the complexity of the Object-Oriented Model?
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Which of the following is directly related to the concept of semantic content in the context of the Object-Oriented Model?
Which of the following is directly related to the concept of semantic content in the context of the Object-Oriented Model?
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What is the primary purpose of data models?
What is the primary purpose of data models?
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What is the main focus of the conceptual model in data abstraction?
What is the main focus of the conceptual model in data abstraction?
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Which of the following is NOT a characteristic of data models?
Which of the following is NOT a characteristic of data models?
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Which of the following is a benefit of creating external models in a database design?
Which of the following is a benefit of creating external models in a database design?
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What is an external schema in data modeling?
What is an external schema in data modeling?
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Which of these is a characteristic of the conceptual model in data abstraction?
Which of these is a characteristic of the conceptual model in data abstraction?
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Which of the following is an advantage of using data models?
Which of the following is an advantage of using data models?
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What is the primary purpose of the external model in data abstraction?
What is the primary purpose of the external model in data abstraction?
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Which of the following is NOT an advantage of the Entity Relationship Model?
Which of the following is NOT an advantage of the Entity Relationship Model?
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What disadvantage does the Entity Relationship Model suffer from?
What disadvantage does the Entity Relationship Model suffer from?
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Which of these is a disadvantage of the Entity Relationship Model related to constraints?
Which of these is a disadvantage of the Entity Relationship Model related to constraints?
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What is the consequence when attributes are removed from entities in the Entity Relationship Model?
What is the consequence when attributes are removed from entities in the Entity Relationship Model?
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What key advantage of the Entity Relationship Model makes it a useful tool for communication?
What key advantage of the Entity Relationship Model makes it a useful tool for communication?
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What are the three main components of a 'Set' in the Network Model?
What are the three main components of a 'Set' in the Network Model?
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What does SQL provide the user?
What does SQL provide the user?
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What is the primary relationship between the hierarchical and the network data models?
What is the primary relationship between the hierarchical and the network data models?
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Which of these represents an aspect of the Hierarchical Model's advantages?
Which of these represents an aspect of the Hierarchical Model's advantages?
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Which of the following statements best describes the 'Schema' in the Network Model?
Which of the following statements best describes the 'Schema' in the Network Model?
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How is an 'Entity' represented in an ERD and how is it related to a relational table?
How is an 'Entity' represented in an ERD and how is it related to a relational table?
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What is the primary difference between the Relational Model and a file system?
What is the primary difference between the Relational Model and a file system?
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What characteristic makes the Object-Oriented Model a 'Semantic Data Model'?
What characteristic makes the Object-Oriented Model a 'Semantic Data Model'?
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Which of these is NOT considered one of the crucial aspects of the Object-Oriented Model?
Which of these is NOT considered one of the crucial aspects of the Object-Oriented Model?
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What is the core function of the SQL engine in a relational database system?
What is the core function of the SQL engine in a relational database system?
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How are business rules important for creating an accurate data model?
How are business rules important for creating an accurate data model?
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Which of these is a potential disadvantage of the Network Model?
Which of these is a potential disadvantage of the Network Model?
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What type of data model is the Extended Relational Data Model (ERDM) considered?
What type of data model is the Extended Relational Data Model (ERDM) considered?
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Which of the following best describes the goal of 'Big Data'?
Which of the following best describes the goal of 'Big Data'?
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Which of these is NOT a characteristic typically associated with 'Big Data'?
Which of these is NOT a characteristic typically associated with 'Big Data'?
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Study Notes
Data Models
- Data models are relatively simple representations of complex real-world data structures.
- They are often graphical to facilitate understanding for designers, programmers and end-users.
- Effective communication between these roles using data models is critical.
- Data models are necessary for organizing data for various users
- Data Models use:
- Entities (person, place, thing, event)
- Attributes (characteristics of an entity)
- Relationships (associations between entities)
- Constraints (restrictions on data to ensure integrity)
- Business rules are useful when understanding entities, attributes, relationships and constraints
Data Modeling Building Blocks
- Entity: Something about which data are collected and stored. Examples: Customer, Student, Patient, Block, Room, Book, CD, Furniture, Wedding, Musical Concert. It represents a specific type of object.
- Attribute: A characteristic of an entity. Examples: CUST_ID, CUST_ADDRESS. They describe the property of an entity.
- Relationship: An association among entities. Examples of types are 1-to-many (1:M), many-to-many (M:N), and one-to-one (1:1). Describe the connection between different instances (entities).
- Constraint: Restrictions placed on the data to ensure integrity. Examples: a student's GPA must be between 0.00 and 4.00, an employee's salary must be between 6,000 and 350,000). Rules that must be followed to maintain data quality.
Business Rules
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Brief, precise, and unambiguous descriptions of policies, procedures or principles within an organization.
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Give descriptions of operations that help create and enforce actions within an organization's environment.
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Examples: A customer may generate many invoices, an invoice is generated by only one customer.
A training session cannot be scheduled for fewer than 10 or more than 30 employees.
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Sources of business rules: Company managers, Policy makers, Department managers, Written documentation, Procedures, Standards, Operations manuals, Direct interviews with end-users.
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Business rules must be rendered in writing, kept up to date and easily disseminated. They define the characteristics of the data as viewed by the company.
Data Model Evolutions
- A summary of data model generations is included in a table. Example table data includes generation, time, data model, examples and comments. Generations include File system, Hierarchical, Network, Relational, Object-oriented, Object-relational, XML and Hybrid DBMS
Hierarchical Model
- Developed in the 1960s to manage large amounts of complex data for manufacturing projects. It uses an upside-down tree structure and 1:M relationships.
- The primary disadvantage is its complexity, difficulty of managing and structural dependencies. There is also a lack of standards.
- It formed the foundation of current data models.
Network Model
- Created to depict relationships more effectively than the hierarchical model by improving database performance and imposing a database standard,
- It's conceptually similar to the hierarchical model but permits a record to have more than one parent, resolving a limitation of the hierarchical model to contain a single set of 1:M relationships.
- A disadvantage is its lack of ad hoc query capability and difficult maintenance that impacted programmers.
Relational Model
- Developed by Codd in the 1970's, relational model is a table-based design that's popular and conceptually simple.
- Relational model excels by storing data in tables and using a common attribute to relate them. The Relational Model is also suitable for microcomputers.
- One advantage is its ability to hide complexities from the end-users, which makes it easier to manage and maintain. Disadvantages are substantial hardware and system software overhead, the difficulty in conceptual simplicity for untrained users to utilize and may promote information problems
Entity Relationship Model (ERM)
- A graphical tool used for data modeling, introduced in 1976 by Chen. It complements the Relational model by graphically depicting entities and relationships.
- Advantages include conceptual simplicity due to visual representation and effective communication due to its visualization. ERM connects to relational models. Disadvantages include limited data manipulation, restricted relationship constraints and loss of information in crowded displays.
Object-Oriented Model
- Combined data and relationships in a single structure called "object."
- It is conceptually useful for representing real-world entities and providing an inheritance feature to simplify complexity.
- A semantic data model, it acts as a basis for object-oriented database management systems.
NoSQL
- A large scale distributed database system and a new approach to data storage. It's based on structure and unstructured data.
- It's better than the Relational Model for storing datasets with less complexity, particularly Big Data.
Degrees of Data Abstraction
- A framework for classifying data models, often used in database design processes.
- The framework proceeds from a high level of abstraction to an increasingly detailed description. There are generally three degrees of abstraction- External, Conceptual and Internal.
- ANSI/SPARE Committee has a framework. External model is specific views of a user, Conceptual Model views the global database, and Internal schema depicts DBMS model..
Other Models
- Extended Relational Data Model (ERDM)
- A semantic data model developed in response to increasingly complex applications.
- It extends the capabilities of the relational model.
Data Models Comparison
- A table presents a comparison of the different data models
- Each row represents a Data Model
- Each column represents the category or aspect compared
Emerging Models
- Big data, a new data approach that makes it easier to manage large amounts of data and derive insight from web-generated data. Big-data modeling is useful for massive amounts of varied and high-volume data.
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Description
Test your knowledge on the advantages and disadvantages of relational and NoSQL databases. This quiz explores key concepts in database models, including SQL, Hadoop, and MapReduce. Dive into how these models handle data processing and storage, particularly in the context of Big Data.
