Section 2 Oracle Acad
Questions and Answers
- 1.
Flat file databases avoid data duplication.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Flat file databases do not avoid data duplication. In fact, they often contain redundant copies of data, which can lead to inefficiency and inconsistency. Flat file databases store data in a simple, text-based format where each line represents a record and each field is separated by a delimiter. This structure does not provide mechanisms to prevent or manage data duplication. Relational databases, on the other hand, use normalization techniques and enforce data integrity constraints to eliminate redundancy and ensure data consistency.Rate this question:
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- 2.
Which of the following are examples of e-business that use database software ?
- A.
Online research paper
- B.
Online clothing store
- C.
Online book store
- D.
Online personal web page
- E.
Online personal shopping service
Correct Answer(s)
B. Online clothing store
C. Online book store
E. Online personal shopping serviceExplanation
The online clothing store, online book store, and online personal shopping service are examples of e-businesses that use database software. These businesses require a database to store and manage their inventory, customer information, and transaction records. The database software allows them to efficiently organize and retrieve data, track sales, and provide personalized shopping experiences for their customers.Rate this question:
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- 3.
Which of the following statements about attributes are true ?
- A.
They must be single valued unless they belong to more than one entity.
- B.
They are often adjectives.
- C.
They describe, qualify, quantify, classify, or specify an entity.
- D.
They have a data type, such as number or character string.
Correct Answer(s)
C. They describe, qualify, quantify, classify, or specify an entity.
D. They have a data type, such as number or character string.Explanation
Attributes are characteristics or properties that describe, qualify, quantify, classify, or specify an entity. They can be single valued if they belong to only one entity or can be multi-valued if they belong to more than one entity. Attributes can often be adjectives that provide additional information about the entity. Additionally, attributes have a data type, such as number or character string, to define the kind of data that can be stored in them.Rate this question:
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- 4.
In a physical data model, an attribute is represented as a/an:
- A.
Instance
- B.
Column
- C.
Foreign Key
- D.
Row
Correct Answer
B. ColumnExplanation
In a physical data model, an attribute is represented as a column. A column is a vertical structure in a table that holds the specific data for that attribute. It represents a specific characteristic or property of the entity being modeled. Each column is labeled with a unique name and has a defined data type, allowing it to store specific types of data. Columns in a physical data model are used to organize and store data in a relational database system.Rate this question:
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- 5.
A/an _________ is a piece of information that in some way describes an entity. It is a property of the entity and it quantifies, qualifies, classifies or specifies the entity.
- A.
Process
- B.
ERD
- C.
Table
- D.
Attribute
Correct Answer
D. AttributeExplanation
An attribute is a piece of information that describes an entity. It is a property of the entity and can be used to quantify, qualify, classify, or specify the entity. In a database or data model, attributes are used to define the characteristics or properties of an entity. They provide additional details and context about the entity, allowing for better organization and understanding of the data.Rate this question:
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- 6.
Data models are drawn to show users the actual Data that their new system will contain; only Data listed on the Diagram can be entered into the Database.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
This statement is true because data models are visual representations of the data that will be stored in a database. These models help users understand the structure and organization of the data in the system. The data listed on the diagram represents the actual data that can be entered into the database. Therefore, any data not listed on the diagram cannot be entered into the database.Rate this question:
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- 7.
Many reasons exist for creating a conceptual model. Choose three appropriate reasons:
- A.
They capture the implementation details of the physical model.
- B.
They model functional and informational needs.
- C.
They model the information flow of data.
- D.
They capture current and future needs.
- E.
They accurately describe what a physical model will contain.
Correct Answer(s)
B. They model functional and informational needs.
D. They capture current and future needs.
E. They accurately describe what a physical model will contain.Explanation
Conceptual models are created for several reasons. Firstly, they model functional and informational needs, which means they help identify the requirements and specifications of a system or process. Secondly, they capture current and future needs, allowing for the consideration of potential changes and improvements. Lastly, they accurately describe what a physical model will contain, providing a clear representation of the data and information flow within the system. These reasons demonstrate the importance of conceptual models in understanding and designing complex systems.Rate this question:
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- 8.
A table must have a primary key.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
A primary key is not required for a table. While it is recommended to have a primary key to uniquely identify each record in a table, it is not mandatory. Tables can still function without a primary key, but it may make it more difficult to manage and manipulate the data within the table.Rate this question:
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- 9.
Each column in a relation is called an entity.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The given statement is false. Each column in a relation is not called an entity. In a relation, each column represents an attribute or a characteristic of the entity, while each row represents a specific instance or record of the entity. The entity itself is represented by the entire relation or table, not by individual columns.Rate this question:
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- 10.
A barred relationship is mapped to a primary key column on the many side, just like any other M:1 relationship.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
In a barred relationship, the primary key column is not mapped on the many side. Instead, it is mapped on the one side. This means that the primary key column is present in the table representing the "one" side of the relationship, rather than the table representing the "many" side. Therefore, the correct answer is false.Rate this question:
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- 11.
What is the purpose of a Unique Identifier ?
- A.
Create an entity that is unlike any other entity aside from itself.
- B.
To uniquely determine a table and columns within that table.
- C.
To identify one unique instance of an entity by using one or more attributes and/or relationships.
- D.
To identify a specific row within a table, using one or more columns and/or foreign keys.
Correct Answer
C. To identify one unique instance of an entity by using one or more attributes and/or relationships.Explanation
A unique identifier serves the purpose of identifying a single, distinct instance of an entity by utilizing one or more attributes and/or relationships. It allows for differentiation between multiple entities and ensures that each instance can be uniquely identified. This helps in organizing and managing data effectively, as well as facilitating efficient retrieval and referencing of specific entities within a system or database.Rate this question:
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- 12.
Unique Identifiers:
- A.
Distinguish one entity from another.
- B.
Distinguish one instance of an entity from all other instances of that entity.
- C.
Distinguish all entities in a database.
- D.
Distinguish nothing.
Correct Answer
B. Distinguish one instance of an entity from all other instances of that entity.Explanation
The correct answer is "Distinguish one instance of an entity from all other instances of that entity." Unique identifiers are used to differentiate one specific occurrence or instance of an entity from all other occurrences or instances of the same entity. They provide a way to uniquely identify and distinguish individual records or objects within a database, ensuring that no two instances are the same.Rate this question:
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- 13.
In the relational model, relationships between relations or tables are created by using:
- A.
Foreign Keys
- B.
Composite Keys
- C.
Candidate Keys
- D.
Primary Keys
Correct Answer
A. Foreign KeysExplanation
Foreign keys are used to create relationships between tables in the relational model. A foreign key is a column or a set of columns in one table that refers to the primary key in another table. This establishes a link between the two tables and allows for the enforcement of referential integrity. By using foreign keys, data integrity can be maintained and relationships can be established between tables, ensuring consistency and accuracy in the database.Rate this question:
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- 14.
One-to-one relationships are transformed into Foreign Keys in the tables created at either end of that relationship.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
In one-to-one relationships, the primary key of one table is used as a foreign key in another table. This is done to establish a connection between the two tables. However, in the given statement, it is mentioned that one-to-one relationships are transformed into foreign keys in both tables created for that relationship. This is incorrect. In a one-to-one relationship, the foreign key is only added in one of the tables, not in both. Therefore, the correct answer is false.Rate this question:
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- 15.
Data modeling is performed for the following reasons:
- A.
The ERD becomes a blueprint for designing the actual system.
- B.
It helps discussions and reviews.
- C.
We do not need data models; we can just start coding right away.
- D.
We draw an ERD solely to please the users; once completed, the ERD is never referred to again as it serves no purpose in the real world.
Correct Answer(s)
A. The ERD becomes a blueprint for designing the actual system.
B. It helps discussions and reviews.Explanation
Data modeling is performed for the following reasons: The ERD becomes a blueprint for designing the actual system. It helps discussions and reviews. Creating an ERD serves as a visual representation of the system and allows stakeholders to understand and provide feedback on the proposed design. It also serves as a guide for developers to implement the system accurately. Without data modeling, there is a higher chance of miscommunication and errors during the development process.Rate this question:
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Mar 21, 2023Quiz Edited by
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Oct 13, 2017Quiz Created by
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