MIS 325 Lecture Notes - Lecture 9: Data Domain, Multivalued Dependency, Unique Key

• School: UT-Austin
• Department: Management Information Systems
• Course: MIS 325
• Professor: Ayvaci

Document Summary

Data structure: a model of the database rather than the database itself. Basic steps for designing a data structure. Subdivide each element into its smallest useful components. Identify tables (entities) and assign columns (attributes) Each table contains information about a single entity. Each piece of information is stored in exactly one place. A table can contain information about two or more entities. Data repeated in two or more rows. The value stored at the intersection of each row and column must be a scalar value. Table must not contain any repeating columns. Second (2nf): every non-key column must be uniquely. Third (3nf): every non-key column must depend only on identified by the entire primary key the primary key. A non-key column can"t be dependent on another non-key column. A table must not have more than one multivalued. The primary key has a one-to-many relationship to dependency non-key columns.