These ER diagram examples for library management highlight the entities and their attributes. Simultaneously, the direct relationships between the details are shown, such as the presence of several CDs and books, each with its ISBN and ISSN. One essential concept to grasp here is that proper symbols comprehend an entity diagram. The entity relations are visible, and their attributes are also visual. The number of entities in these ER diagram examples for library management is based on existing entities. The second critical aspect is to understand the relationships between the entities themselves. When looking for an ER diagram, creators usually consider how many entities they will be working with.