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.
Trending nowThis is a popular solution!
Chapter 3 Solutions
Database Systems: Design, Implementation, & Management
- An in-memory database (IMDB) is a database management system that stores the entire database in _______. a. random access memory b. read-only memory c. distributed servers d. virtual memoryarrow_forwardAccess path A database table is composed of records and fields hold data. Data is stored in records. A field is a part of a record and contains a single piece of data for the subject of the record. The access path for finding the list of books is AUTHOR: AuthorID, Lname BOOKAUTHOR: AuthorID, ISBN BOOKS: Pubdate, ISBNarrow_forwardSQL databases conform to ACID properties. Briefly describe the ACID properties, and state the purpose of each. How does conformance to ACID properties affect the performance of SQL databases?arrow_forward
- How is the processing of SQL DDL statements (such as CREATE TABLE) different from the processing required by DML statements?arrow_forwardWhat does it mean for a database to have entity as well as referential integrity?arrow_forwardWhat is the role of "self-referential integrity" in database modeling?arrow_forward
- What would occur if the referential integrity of a database were compromised? What errors do you commit most frequently?arrow_forwardIf a database's referential integrity were to be broken, what would happen? Which mistakes do you make most often?arrow_forwardWhat happens if your database's referential integrity is broken? What mistakes are often made?arrow_forward
- Database 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 LearningEnhanced Discovering Computers 2017 (Shelly Cashm...Computer ScienceISBN:9781305657458Author:Misty E. Vermaat, Susan L. Sebok, Steven M. Freund, Mark Frydenberg, Jennifer T. CampbellPublisher:Cengage Learning
- Database Systems: Design, Implementation, & Manag...Computer ScienceISBN:9781305627482Author:Carlos Coronel, Steven MorrisPublisher:Cengage LearningPrinciples of Information Systems (MindTap Course...Computer ScienceISBN:9781305971776Author:Ralph Stair, George ReynoldsPublisher:Cengage LearningPrinciples of Information Systems (MindTap Course...Computer ScienceISBN:9781285867168Author:Ralph Stair, George ReynoldsPublisher:Cengage Learning