Primary Key:
A Primary Key in a
Example:
Students in Universities are assigned a unique registration number.
Therefore, in a STUDENT database table, the attribute “reg_no” acts as primary key.
Foreign Key:
Foreign Key is a column in a relational database table which provides a relation between two tables. It provides a cross reference between tables by pointing to primary key of another table.
Example:
In STUDENT database table, the attribute “reg_no” acts as primary key and in COURSE database table in which the student selects his or her course, the same “reg_no” acts as foreign key for the STUDENT table.
Many to one relationship:
When one record in a database table is associated with one or more records in another table, the relationship between the two tables is referred as many to one relationship. It is also represented as M:1 relationship.
RELATIONAL DIAGRAM:
Relational Diagram is also known as Entity Relational Diagram. It is used to define the conceptual view of the database as viewed by the end user. It is used to depict the database’s main components: entities, relationships and attributes. It describes how data is related to each other.
Given database tables:
Table Name: STORE
STORE_CODE | STORE_NAME | STORE_YTD_SALES | REGION_CODE | EMP_CODE |
1 | Access Junction | 1003455.76 | 2 | 8 |
2 | Database Corner | 1421987.39 | 2 | 12 |
3 | Tuple Charge | 986783.22 | 1 | 7 |
4 | Attribute Alley | 944568.56 | 2 | 3 |
5 | Primary Key Point | 2930098.45 | 1 | 15 |
Table Name: REGION
REGION_CODE | REGION_DESCRIPT |
1 | EAST |
2 | WEST |
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Chapter 3 Solutions
Bundle: Database Systems Design, Implementation, & Management, Loose-leaf Version, 13th + MindTapV2.0, 1 term Printed Access Card
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- Which one of the 4 Entities mention in the diagram can have a recursive relationship? If a new entity Order_Details is introduced, will it be a strong entity or weak entity? If it is a weak entity, then mention its type (ID or Non-ID, also Justify why)?arrow_forwardPlease answer the JAVA OOP Programming Assignment scenario below: Patriot Ships is a new cruise line company which has a fleet of 10 cruise ships, each with a capacity of 300 passengers. To manage its operations efficiently, the company is looking for a program that can help track its fleet, manage bookings, and calculate revenue for each cruise. Each cruise is tracked by a Cruise Identifier (must be 5 characters long), cruise route (e.g. Miami to Nassau), and ticket price. The program should also track how many tickets have been sold for each cruise. Create an object-oriented solution with a menu that allows a user to select one of the following options: 1. Create Cruise – This option allows a user to create a new cruise by entering all necessary details (Cruise ID, route, ticket price). If the maximum number of cruises has already been created, display an error message. 2. Search Cruise – This option allows to search a cruise by the user provided cruise ID. 3. Remove Cruise – This op…arrow_forwardI need to know about the use and configuration of files and folders, and their attributes in Windows Server 2019.arrow_forward
- Southern Airline has 15 daily flights from Miami to New York. Each flight requires two pilots. Flights that do not have two pilots are canceled (passengers are transferred to other airlines). The average profit per flight is $6000. Because pilots get sick from time to time, the airline is considering a policy of keeping four *reserve pilots on standby to replace sick pilots. Such pilots would introduce an additional cost of $1800 per reserve pilot (whether they fly or not). The pilots on each flight are distinct and the likelihood of any pilot getting sick is independent of the likelihood of any other pilot getting sick. Southern believes that the probability of any given pilot getting sick is 0.15. A) Run a simulation of this situation with at least 1000 iterations and report the following for the present policy (no reserve pilots) and the proposed policy (four reserve pilots): The average daily utilization of the aircraft (percentage of total flights that fly) The…arrow_forwardWhy is JAVA OOP is really difficult to study?arrow_forwardMy daughter is a Girl Scout and it is time for our cookie sales. There are 15 neighbors nearby and she plans to visit every neighbor this evening. There is a 40% likelihood that someone will be home. If someone is home, there is an 85% likelihood that person will make a purchase. If a purchase is made, the revenue generated from the sale follows the Normal distribution with mean $18 and standard deviation $5. Using @RISK, simulate our door-to-door sales using at least 1000 iterations and report the expected revenue, the maximum revenue, and the average number of purchasers. What is the probability that the revenue will be greater than $120?arrow_forward
- Database Systems: Design, Implementation, & Manag...Computer ScienceISBN:9781305627482Author:Carlos Coronel, Steven MorrisPublisher:Cengage LearningDatabase Systems: Design, Implementation, & Manag...Computer ScienceISBN:9781285196145Author:Steven, Steven Morris, Carlos Coronel, Carlos, Coronel, Carlos; Morris, Carlos Coronel and Steven Morris, Carlos Coronel; Steven Morris, Steven Morris; Carlos CoronelPublisher:Cengage Learning
- COMPREHENSIVE MICROSOFT OFFICE 365 EXCEComputer ScienceISBN:9780357392676Author:FREUND, StevenPublisher:CENGAGE LNp Ms Office 365/Excel 2016 I NtermedComputer ScienceISBN:9781337508841Author:CareyPublisher:Cengage
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