• MySQL tutorial


    MySQL tutorial MySQL is the most popular relational database management system. In web application, MySQL is one of the best RDBMS (relational database management system) application software. In this tutorial, you will quickly master the basic knowledge of MySQL, and easy to use MySQL database. What is a database? Database is a warehouse that organizes, […]

  • Graphic SQL, this is too image!


    Author Tony, who doesn’t cut her hairSource https://blog.csdn.net/horses/… This paper introduces the design idea of relational database: everything is relational in SQL. There are many great design concepts and ideas in the computer field, such as: In UNIX, everything is a file. In object-oriented programming languages, everything is an object. The same is true of […]

  • The intermediary model of design pattern


    Mediator model Intro Mediator pattern, a mediation object is used to encapsulate a series of object interactions.Mediators make the objects do not need to explicitly refer to each other, so that they are loosely coupled and can change their interactions independently. The mediation pattern defines a single (mediation) object to encapsulate the interaction between a […]

  • Equivalent connection and natural connection


    1. First of all Tuples: rows in relationships Properties: columns in relationships Relation operation: R (a, B, C, d) and S (B, C, y, z) are two relations; Select [get qualified tuples in relation R] Projection [get some attribute columns in relation R to form a new relation] Join [Select tuples satisfying conditions among attributes […]

  • Combined with RBAC model to explain the requirements of authority management system and table structure creation


    In the previous articles in this issue, we have introduced a lot about the use of spring security and RBAC’s role-based permission control model. However, although many friends have understood the RBAC control model, there are still many problems hindering their further development. For example: How to create the table structure of RBAC model? Specific […]

  • Mybatis series (5) – Basics – many to one


    Step 1: run first, see the effect, and then learn Step 2: imitation and troubleshooting Step 3: many to one relationship Step 4: look at the effect before learning Step 5: modify Product.java Step 6: Product.xml Step 7: mybatis- config.xml Step 8: testmybatis Runnable project steps Step 10: Exercise – modify the many to one […]

  • Notes on. Net core dependency injection framework diagram


    Recently, I was looking at Mr. Jiang Jinnan《 ASP.NET The core 3 framework reveals the secrets, drawing a summary of the contents of Chapter 3 and Chapter 4. Please refer to Mr. Jiang’s blog: https://www.cnblogs.com/artech/p/inside-asp-net-core-03-01.html       Figure 1 the relationship between iservicecollection and iserviceprovider & definition of servicedescriptor       Figure 2 […]

  • Accelerate high concurrency system with NoSQL


    With the advent of the Internet tide, more and more websites and application systems need the support of massive data. The requirements of high concurrency, low latency, high availability and high expansion have not been met in the traditional relational database, or the relational database has been unable to cope with these requirements. After decades […]

  • Mybatis series (6) – Basics – many to many


    Step 1: define a many to many relationship Step 2: table structure Step 3: import data Step 4: run first, see the effect, and then learn Step 5: imitation and troubleshooting Step 6: entity class Step 7: map the file Step 8: modify mybatis- config.xml Step 9: query operation Step 10: build relationships Step 11: […]

  • Notes on database system and principle


    Three level model structure Mode, external mode (sub mode), internal mode Two level mapping External schema / schema mapping → guarantee logical independence of data Internal mode / mode influence → guarantee the physical independence of data Introduction to relational database E.f.codd of IBM is the most systematic and strict method to put forward relational […]

  • Analyzing the relationship between spring beans through examples


    This article mainly introduces how to analyze the relationship between spring beans through examples. The example code is introduced in detail, which has certain reference value for everyone’s study or work. Friends in need can refer to it Two kinds of relations: Inheritance and dependence 1、 Inheritance relationship Address.java package com.gong.spring.beans.autowire; public class Address { […]

  • RDN in LDAP


    What is RDN and what is the relationship between RDN and DN? Many children’s shoes that are exposed to LDAP for the first time are often confused by a lot of names. The Chinese translation of RDN (relative distinguished name) is a relatively proper name. Generally refers to the leftmost part of the DN comma, […]