Database is a collection of interconnected data that constitutes a common data base on all applications of an information system. Architecture of a database consists of three layers: Physical, global logical level and a local logic level. The advantages of using a database are redundancy control, system integrity, the use of common data, data protection, data standardization and optimization of the unit. Models of databases are relational model, network model, the hierarchical model and the object model. The main stages of database design are requirements gathering and analysis, conceptual modeling, logical modeling and physical modeling. The most used conceptual model is a model of entities and relationships. Chen in his article "The Entity - relationship model: TOWARD A UNIFIED VIEW OF DATA" in 1977 introduced a model with diagrams showing the real world. E - R model uses a more natural view of the world consisting of entities and relationships. The entity is real or abstract phenomenon that can be identified. Relationships are relations between the entities. Attributes are properties which are describing an entity. The key uniquely identifies the entity. Steps in detecting entities, relationships and attributes: 1. Detection of nouns (entities and attributes) and a verb (relationships), 2. Determine what attributes describe the entity, 3. drawing diagrams and 4. writing the accompanying text. Based on a warehouse receipt, we presented some of the ER model, and those are: Batini, Ceri & Navathe, Chen, Elmasri & Navathe, Korth & Silberschatz, Martin, McFadden & Hoffer and Oracle's case method (Barker). The extended model of entities and relationships was developed from the late 1970s to enable the achievement of demanding and precise database. The extended model of entities and relationships introduces new concepts such as class, superclass, specialization, generalization and inheritance.