ERD&PIM

An entity-relationship model (ERM) in software engineering is an abstract and conceptual representation of data. Entity-relationship modeling is a relational schema database modeling method, used to produce a type of conceptual schema or semantic data model of a system, often a relational database, and its requirements in a top-down fashion.



A sample ER diagram
Diagrams created using this process are called entity-relationship diagrams, or ER diagrams or ERDs for short. The definitive reference for entity relationship modelling is generally given as Peter Chen's 1976 paper.
An entity may be defined as a thing which is recognized as being capable of an independent existence and which can be uniquely identified. An entity is an abstraction from the complexities of some domain. When we speak of an entity we normally speak of some aspect of the real world which can be distinguished from other aspects of the real world
Personal information management (PIM) refers to both the practice and the study of the activities people perform in order to acquire, organize, maintain, retrieve and use information items such as documents (paper-based and digital), web pages and email messages for everyday use to complete tasks (work-related or not) and fulfill a person’s various roles (as parent, employee, friend, member of community, etc.).
One ideal of PIM is that we always have the right information in the right place, in the right form, and of sufficient completeness and quality to meet our current need. Technologies and tools such as personal information managers help us spend less time with time-consuming and error-prone activities of PIM (such as looking for information). We then have more time to make creative, intelligent use of the information at hand in order to get things done or simply, to enjoy the information itself.