An entity relationship diagram (ERD) shows the relationships of entity sets stored in a database. ... By defining the entities, their attributes, and showing the relationships between them, an ER diagram illustrates the logical structure of databases. ER diagrams are used to sketch out the design of a database.
A schema in psychology and other social sciences describes a mental concept. It provides information to an individual about what to expect from diverse experiences and circumstances. These schemas are developed and based on life experiences and provide a guide to one's cognitive processes and behavior.