MIS 2-29 - -one attribute that determines the other...

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Database systems are: - users - database application - database management system (DBMS) - Database Foreign key: - primarily a primary key from one table placed into another table. - the key is called a foreign key in the table that received the key Referential Integrity: - states that every value of foreign key must match a value of an existing primary key. - If EmpID = 4 in EMPLOYEE has a DeptID = 7 (a foreign key), a department with DeptID = 7 must exist in DEPARTMENT. - The primary key value must exist before the foreign key value is entered. - Primary key will not be deleted until all foreign key values are gone. Null value - means that no data was entered Functional Dependency - relationship between attributes in which one attribute (or group of attributes) determines the value of another attribute in the same table.
Image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: -one attribute that determines the other attributes = primary key Determinants-the attribute (or attributes) that we use as the starting point is called a determinant. Candidate Key-A candidate key of a relation will functionally determine all other attributes in the row. -A primary key of a relation will functionally determine all other attributes in the row. Normalization-a process of analyzing a relation to ensure that it is well formed-if a relation is normalized, rows can be inserted, deleted, or modified without creating update anomalies-a relation is considered normalized when : EVERY determinant is a candidate key. This is Boyce-Codd Normal Form (BCNF)...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern