There are several levels of data abstraction in a database

There are three levels of data abstraction in the database: physical level, logical level, and view level.

This article introduces the data abstraction of database to everyone, so that everyone can understand what data abstraction is and the composition system of data abstraction. I hope it will be helpful to you. [Video tutorial recommendation: MySQL tutorial]

What is data abstraction

Database systems are composed of complex data structures. In order to simplify the interaction between users and the database, internal irrelevant details will be hidden from users. This process of hiding irrelevant details from the user is called data abstraction.

Data abstraction architecture

There are three abstraction levels in data abstraction, namely:

1, Physical Level

The physical level is the lowest level of data abstraction, which describes how the data is actually stored in the database; we can get complex data structure details at this level.

Example: Suppose we store student information in the student table

At a physical level, these records can be described as storage blocks (bytes, gigabytes, terabytes) in memory wait). However, these details are usually hidden from programmers, and generally, we cannot intuitively feel them; this is mainly provided to database vendors for research.

2. Logical level

The logical level is the middle level of the 3-level data abstraction architecture. It describes the data stored in the database, such as: what data is stored , what is the relationship between the stored data, etc.

Example: Still an example of storing student information in the student table

At the logical level, these records can be described as fields and attributes and their data types, and the relationships between them can implemented logically. This is mainly considered by programmers or database administrators. Programmers usually work at this level, setting the structure of data tables and various data types.

3. View level

The view level is the highest level of data abstraction. It describes the interaction between the user and the database system. Data can be added to the user view interface. Delete, modify, check and other operations.

Example: Still an example of storing student information in the student table

At the view level, the user only needs to use the graphical user interface (GUI) and the system Interact and enter details on the screen. They don't know how the data is stored and the details of what data is stored; these details are hidden from them.

Users do not need to know the details of the database schema, such as data structure, table definition, etc.; users only need to know the data returned to the view level after being obtained from the database.

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