ITSS 4300 Lecture Notes - Lecture 15: Data Model, Database Design, Cardinality

• School: UT-Dallas
• Department: Information Technology and Systems
• Course: ITSS 4300
• Professor: Dogan

Document Summary

Data model conceptual of data needs before knowing database: exm. Er diagram: blueprint for a database design. Important of database is how we store it. Set of concepts and graphical symbols to create conceptual schemas. Something that can be identified and the user want to track. Entity class collection of entities of a given type. Entity instance the occurrence of a particular entity: what you put in. Usually many instances of an entity in an entity class: what instances you put in entities. Customer: the entity class and two entity instances. Are attributes that name or identify, entity instances. Cardinalities how many instances can be associated with one table. Means count and is expressed as a number. Maximum cardinality max number of entity instances that can participate in a relationship. Minimum cardinality min number of instances that must participate in a relationship. Each instance in one table can be associated with another table.