Computer Science 1032A/B Lecture Notes - Lecture 2: Unique Key, Relational Database, Foreign Key

• School: Western University
• Department: Computer Science
• Course: Computer Science 1032A/B
• Professor: Louis Magguilli

Document Summary

Relational database: groups of data are related to each other in a meaningful way. Data hierarchy : bytes or characters fields or columns records or rows table or file. Components of a database: tables or files + relationships among rows + metadata. Metadata: description of the structure of the database. Primary keys: column(s) that identify unique row in table. Databases using tables, primary keys & foreign keys. Getting the right content to the right person in the right format at the right time. Effectively and efficiently storing and processing data. Spreadsheets keep lists of a single concept whereas databases keep lists that involve multiple themes. Oracle is the most used database management system. A relationship (can always be read forwards and backwards) Captures how the entities are related to one another. Primary keys are necessary to uniquely identify the instance of each entity. Relationships can also have attributes that describe properties of the relationships, doesn"t describe the entities themselves.