Junction tables sit between two tables that form a many-to-many relationship. The junction table typically has a concatenated primary key that is made up of the primary keys from each of the original two tables, and describes the intersection of their val
- [Instructor] In your data model, you may have…created two tables that are joined together…in a many-to-many relationship.…If that's the case, now is the time to…resolve that into a format that can be…implemented in the database management system.…We do this by creating a third table,…called a "junction table", that sits between the other two.…The most common example of a many-to-many…relationship is the case of a class schedule,…which includes the table storing information…about students, and the table that stores…information about various classes that are being offered.…We'll note that each student can take…between zero and several classes,…and each class would have several students enrolled.…
Thus, a many-to-many relationship…exists between these two tables.…This accurately represents the…real world situation that we're trying to capture.…But in order to actually create this in the database,…we need to create an intermediary table…that sits between the students and the…classes table that further describes…
Adam Wilbert covers the basics of relational database design, regardless of whether you use Access, FileMaker, Open Office, or SQL Server. Learn how to prevent data anomalies, gather requirements to plan your design, and develop a conceptual data model—translating your ideas into components like tables, relationships, queries, and views. Plus, learn about logical design considerations that can help you construct a database that is easy to maintain.
- Identify the three rules of relations.
- Summarize the four stages of developing a relational database.
- Describe a strategy one might use to ensure a database remains flexible in terms of the questions a user can ask.
- Explain how to avoid scope creep.
- Recall the characteristics of a Lookup Table.
- Recognize situations in which denormalization would be beneficial.
- Understand the types of relationships modeled by junction tables.
- Define referential integrity.
Skill Level Beginner
1. Relational Database Basics
Relational structures3m 46s
2. Preventing Data Anomalies
3. Gathering Requirements
4. Developing the Conceptual Data Model
5. Normalizing Your Data
6. Logical Design Considerations
7. Developing the Physical Database
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