A Guide to SQL
9th Edition
ISBN: 9781111527273
Author: Philip J. Pratt
Publisher: Course Technology Ptr
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Expert Solution & Answer
Chapter 2, Problem 1RQ
Explanation of Solution
Entity:
Entity refers to the basic building block of data collected regarding a person, place, event, or thing.
- Entity can be defined as an object in the system that has to be modelled and about which information has to be stored.
- The property of entity refers to attribute and the association between entities refers to a relationship.
- Rectangles with either round or square corners are used to represent an entity.
- Entity is described by a singular noun spelled in capital letters.
- Some common examples of entities are Employee, Student, Lecturer, etc.
Example of entity:
The example of an entity is given below:
- Student – the student is the name of the person, who collects the details of the student information. Therefore, here the STUDENT acts as an entity.
- Lecturer - the lecturer is the person name, who collects the details of lecturer information. Therefore, here the Lecturer acts as an entity.
- Department - the department is the person name that collects the details of department information. So, here the Department acts as an entity.
The following example shows “Student” entity, “Lecturer” entity, and “Department” entity of the “college”
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Chapter 2 Solutions
A Guide to SQL
Ch. 2 - Prob. 1RQCh. 2 - What is an attribute?Ch. 2 - What is a relationship? What is a one-to-many...Ch. 2 - Prob. 4RQCh. 2 - What is a relation?Ch. 2 - Prob. 6RQCh. 2 - Prob. 7RQCh. 2 - How do you qualify the name of a field, and when...Ch. 2 - Prob. 9RQCh. 2 - What is a primary key? What is the primary key for...
Ch. 2 - Prob. 11RQCh. 2 - Prob. 12RQCh. 2 - Define second normal form. What types of problems...Ch. 2 - Define third normal form. What types of problems...Ch. 2 - Prob. 15RQCh. 2 - Prob. 16RQCh. 2 - List the changes you would need to make to your...Ch. 2 - Prob. 1TDCh. 2 - Prob. 2TDCh. 2 - Prob. 3TDCh. 2 - Prob. 4TDCh. 2 - Prob. 5TDCh. 2 - Prob. 1CATCh. 2 - Identify the functional dependencies in the...Ch. 2 - Prob. 3CATCh. 2 - Determine the functional dependencies that exist...Ch. 2 - Prob. 2SCGCh. 2 - Prob. 3SCG
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