What Is Logical Data And Physical Data In Databases?


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Connor Sephton Profile
Connor Sephton answered
Those who study systems engineering are very familiar with data modeling. However, for those who are just starting and learning the basics, knowing what it is all about and its application is a must. Technically, data modeling is an instrument that is used by businesses and other organizations in determining their data requirements. It comes in three levels namely conceptual data, logical data model and physical data model. These stages have to be followed step by step because one level becomes even more difficult to comprehend.

A data's logical concept can be attributed to its graphical representation wherein tables and other entities of a data are represented. It can also include columns, tables and fields. As such, a logical data is usually characterized by diagrams. These diagrams are also made as basis of a physical data model as soon as they have been approved and validated. In each entity, a primary key is assigned and mentioned. There are also other foreign keys which function is to identify the relationship that exists between the entities. In a logical data, normalization will also take place. However, one thing is certain and that is how the modeller of a logical data strives to provide more details about a certain data.

On the other hand, a physical data encompass keys, domains, data types and stored procedures. Most importantly, it is the one responsible in giving rules on validation. It also provides access constraints. In order to identify the relationships that exist between the tables, foreign keys will have to be used. Moreover, there will be demoralization that will take place. Modeller gives out information on how a certain database is supposed to be implemented. Of the different kinds of models, physical data stand out because of certain physical considerations.
amber Jhon Profile
amber Jhon answered
In Databases Logical data and the Physical data are the data models. Both have different features. Logical data gives the graphical representation. It includes all entities, tables and relationships. It gives all of the information about attributes,columns and fields. The primary key is mentioned for each entity. There are foreign keys which identify the relationship between different entities. Normalization also occurs in logical data. In a logical data model, unlike physical data, the data modeler attempts to give more details about the data.

In the physical data, tables, stored procedures, domains, columns, keys, and data types are included. Moreover, it also gives validation rules, database triggers and access constraints. In this case foreign keys are used for identification of relationships between tables. In physical data demoralization occurs. Because of physical considerations, this model is very different from the other models. In this model unlike logical data, modeler specifies that how it will be implemented on database.

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