database table design best practices

A popular understanding of three paradigms is of great benefit for database design. In the database design, in order to better apply three paradigms, it is necessary to understand the three paradigms in a popular sense.1. The first paradigm: 1NF is an atomic constraint on attributes, requiring attributes to be atomic

previous action Audit User table: Required approver Audit Organization Structure table: The organizational structure needed to query 3. Condition determination Decision table: The results of the process are judged by the complex workflow, for example, the number of days to leave is more than n days for XXX actions Starting with "form", you can either "decide" o

Use of MySQL database, without exception in the design will encounter the primary key selection, generally in the following three choose one or more, self-growth columns, UUID and Uuid_short, the focus of the characteristics of the primary key, presumably everyone knows very well, I will not elaborate, in the InnoDB engine , choose which kind of primary key is better, the net also has many posts to have the

Tags: cWeb using os IO data art ar problemDue to the needs of the project, we configure some infrequently variable constants through the data fields and update the data through the database fields when the system is initialized. The following is a description of the example.I have a watch like this., you will find that Meterkindid and Measureid are code, only the data dictionary configured by the data can parse out the values we want, the following is

Tags: 1nf 2nf 3nfThe three paradigms of database design (nomorlization)1NF: Atomicity, that is, each field cannot be split.2NF: Uniqueness, that is, each table only describes an entity, the entity must have a primary key, the non-primary key to fully rely on the primary key, because it is said to be completely dependent, because in the case of a combined primary

Label:　　After our last analysis, the database to have the most basic four tables, user tables, Message table, type table, like table, Comment table, and then we look at how to design it First, let's be clear, the code for the

Tags: ISS foreign key Lis __str__ detail Avatar Database City NidTable Relationship Design publishing house table relationship# Publisher Table class Publisher (models. Model): name = models. Charfield (max_length=32) addr = models. Charfield (max_length=128) phone = models. Integerfield () def __str__ (self): return s

and problems. DDD is good, but to apply it to your project requires a lot of time and effort to analyze its implementation process and the requirements of the project team. Of course, man-made factors and external environmental problems we do not consider here, after all, those are things we can not change, here only to discuss with our closely related issues. 1.1.1 "How to use UMLwe all know what UML is doing, and it is a standard system modeling language, which makes it easy for us to an

Now, we use the above stored procedure to compute all child nodes and corresponding layers of the node Fruit. The query results are as follows: From the above implementation, we can see that the design scheme using Left and Right Value encoding is used. In the tree query time, only two database queries are required, eliminating recursion, in addition, the query conditions are numerical comparisons, and t

The design of the table ' content ' cannot be modified. It's in a read-only database.

What is the role of the Design table field when we are building the database?

Take a practical work as an example, in a financial system, from the business perspective of investors and borrowers of these two types of users, but from the user category to see the enterprise users and individual users, I would like to build a table how to do better.Way One:User tableUser_person table, User_enterprise tableWay two:User tableUser_investor Investor form, User_borrower Borrower's Watch No