1 / 5

Primary key and foreign key relationships

Primary key and foreign key relationships. IST359 M005. Yang Wang ywang@syr.edu 342 Hinds http://blackboard.syr.edu. Cardinality. 1-1 relationship 1-many relationship Many-many relationship. 1-1 relationship. Students table student_id (primary key) student_ssn (foreign key)

Download Presentation

Primary key and foreign key relationships

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Primary key and foreign key relationships IST359 M005 Yang Wang ywang@syr.edu 342 Hinds http://blackboard.syr.edu

  2. Cardinality • 1-1 relationship • 1-many relationship • Many-many relationship

  3. 1-1 relationship • Students table • student_id (primary key) • student_ssn (foreign key) • SSNs table • ssn (primary key) Students (student_ssn) references to SSNs (ssn) 1 student has only 1 SSN

  4. 1-many relationship

  5. Many-many relationship This M-M Relationship has been resolved into two 1-M relationships

More Related