Oracle-three paradigm

What is paradigm:

Set the rules to be followed by the database. It is defined by a brother surnamed Fan.

 

 

Three paradigm goals:

There is no redundant data, that is, no duplicate data is stored, that is, data standardization.

Standardization refers to the process of removing redundancy from your data storage. If the database design is fully standardized, when all the tables are connected by keywords, no data repetition will appear ). The advantage of standardization is obvious. It avoids data redundancy and naturally saves space. It also provides a fundamental guarantee for data consistency, this eliminates data inconsistency and increases efficiency.

 

First paradigm:

1. A primary key is required.

2. The column cannot be divided. Of course, it cannot be repeated. You do not need to divide it into two fields if you can use one field.

Second paradigm: some dependencies do not exist
1. Non-primary key fields do not depend on non-primary key fields or some primary key fields (the two fields are merged into the primary key.

2. In case of 1, you need to split the table into multiple tables.

Third paradigm: there cannot be transmission dependencies. Any other fields that are not the primary key must directly rely on the primary key.