A car's ignition switch serves several purposes. First, it allows you to control the power to many of the car's accessories, preventing accessories from running down the car's battery when the car is parked for a long period of time.
Cardinality is the term used in database relations to denote the occurrences of data on either side of the relation. In the common data architecture, cardinality is documented with data integrity but not with data structure. There are several types of cardinality defining relationships between occurrences of entities on two sides of the line of relationships.
Sybase Adaptive Server Enterprise. A relational database is a collection of data items organized as a set of formally-described tables from which data can be accessed or reassembled in many different ways without having to reorganize the database tables. The relational database was invented by E. F. Codd at IBM in 1970. relational database is a set of tables containing data fitted into predefined categories. Each table (which is sometimes called a relation) contains one or more data categories in columns. Each row contains a unique instance of data for the categories defined by the columns.