Before revision: It is defined as the ratio of the number of instances/records in the system (mostly implemented as a Database) that represent real world [ entities ] and the number of entities that exist (in the real world) and should be represented in the information system according to its purpose.
After revision: It is defined as the ratio of the number of instances/records in the system (mostly implemented as a Database) that represent real world [ ] and the number of entities that exist (in the real world) and should be represented in the information system according to its purpose.