COB 204 Lecture Notes - Lecture 3: Database, Unique Key, Spreadsheet
Document Summary
Tables- data is organized into tables, rows: records, columns: ields. Primary key-the primary key of a relaional table uniquely ideniies each record in a table. Foreign key-a column or group of columns that. Relaionships-exist between two database tables when one table has a foreign. Data organized in layers: bit, byte, ield, record, data ile (table), database (smallest to largest) Data type-speciies the kind of data a ield can contain and how the ield is used. In a relaional database: 1 to 1 relaionship, 1 to many relaionship, many to many relaionship. In a relaional database, it uses a 3rd party to establish many to many relaionship ex. customer orders books.
