When you are examining the relationship of certain things within of a set, then you need to know how to make an ER diagram. This diagram will give you help in identifying the relationships. We have a collection of ER diagrams examples that you can use as reference in making your own ERD.
An entity relationship diagram (ER Diagram) shows the relationships of entity sets stored in a database. An entity in this context is a component of data. In other words, ER diagrams illustrate the logical structure of databases. This diagram is usually drawn in a graphical form as boxes (entities) that are connected by lines (relationships) which express the associations and dependencies between entities. An ER model can also be expressed in a verbal form, for example: one building may be divided into zero or more apartments, but one apartment can only be located in one building. Learn the following ER diagram examples below.
There are five main components of an ERD: Entities, which are represented by rectangles. An entity is an object or concept about which you want to store information. Actions, which are represented by diamond shapes, show how two entities share information in the database. Attributes, which are represented by ovals. A key attribute is the unique, distinguishing characteristic of the entity. Connecting lines, solid lines that connect attributes to show the relationships of entities in the diagram. Cardinality specifies how many instances of an entity relate to one instance of another entity.
Choose from the collection of example diagrams above to understand the ERD. Learn more about the other educational diagrams by browsing through our categories or looking it up on the search column!