The data schema is also a model, which is the form of a database of operational means for providing information representation, and is a tool used in databases to surprise the real world. The data model is divided into 3 types according to different application levels, namely conceptual data model, logical data model and physical data model.
conceptual data Model, also known as conceptual model, is an objective-oriented, user-oriented model, independent of the specific database management system and independent of the specific computer platform.
The logical data model, also known as the roadbed model, is a model for database system, which is the intermediate level between the conceptual model and the computer. The conceptual model is only represented in the database after the conversion is called a logical type. At present, there are many kinds of logical models, including hierarchical model, relational model, mesh model, object-oriented model and so on.
physical data model, also known as physical model, is a model for computer physical representation. This model is the representation of the data model on the physical structure of the computer. Typically, the data model consists of three parts: data structure, data manipulation, and integrity constraints, which are also known as the
three main elements of the model.
The Oracle Getting Started data model
