MyBatis beginner's quick start 01 (basic use of addition, deletion, modification and query)

premise 1. Understand database, JDBC, maven and other basic knowledge. 2. This paper uses idea and maven to illustrate. 1, Introduction to MyBatis 1. Official profile MyBatis is an excellent persistence layer framework, which supports custom SQL, stored procedures and advanced mapping. MyBatis eliminates almost all JDBC code and the wor ...

Posted by fox_m on Fri, 15 Apr 2022 17:37:59 +0300

Spring Cloud learning notes (3 / 3)

108_ Installation of Linux version of Nacos Expected, 1 Nginx+3 nacos registries +1 mysq Make sure you are installing and using in the environment: 64 bit OS Linux/Unix/Mac, Linux system is recommended.64 bit JDK 1.8+; Download to configure.Maven 3.2.x+; Download to configure.Only three or more Nacos nodes can form a cluster. link Nacos d ...

Posted by Lee on Fri, 15 Apr 2022 08:30:50 +0300

MySQL notes (dark horse III)

DQL: query statement Sort queryAggregate functionGrouping queryPaging query constraintRelationship between multiple tablesnormal formBackup and restore of database DQL: query statement Sort query Syntax: order by clause order by sort field 1, sort by 1, sort field 2, sort by 2 Sort by: ASC: ascending, default.DESC: descending. ...

Posted by cheesehead on Fri, 15 Apr 2022 02:36:28 +0300

MySQL connection query

Create sample table Creation of Table 1 create table Double list 1 ( id int PRIMARY key, name varchar(30) ) insert into Double list 1 select 1,'Xiao Ming'; insert into Double list 1 select 0,'Zhang San'; insert into Double list 1 select 0,'Boiling sheep'; insert into Double list 1 select 0,'Li Yang'; insert into Double list 1 select 0,'G ...

Posted by goa103 on Thu, 14 Apr 2022 00:47:29 +0300

MySQL exercises ~ 45

Create tables and add data -- classic SQL Exercises CREATE TABLE STUDENT8 (SNO VARCHAR(3) NOT NULL, SNAME VARCHAR(4) NOT NULL, SSEX VARCHAR(2) NOT NULL, SBIRTHDAY DATETIME, CLASS VARCHAR(5)); CREATE TABLE COURSE (CNO VARCHAR(5) NOT NULL, CNAME VARCHAR(10) NOT NULL, TNO VARCHAR(10) NOT NULL); CREATE TABLE SCORE (SNO VARCHAR(3) NOT NULL, CNO ...

Posted by _confused_ on Wed, 13 Apr 2022 00:52:46 +0300

Chapter 3 relational database standard language SQL

Chapter 3 relational database standard language SQL The whole content of this paper comes from the introduction to database system (5th Edition) - written by Wang Shan and SA Shixuan 3.1 SQL overview Comprehensive unificationHighly unprocessedSet oriented operation modeProvide multiple ways to use the same syntax structureThe grammar is ...

Posted by khovorka on Mon, 11 Apr 2022 19:09:21 +0300

Installation steps, basic commands and related functions of Ubuntu Linux C sqlite3

catalogue sqlite3 installation steps sqlite3 basic commands Enter sqlite mode command System command (point command -- with "." (beginning) sqlite statement (with ";) (end) sqlite related functions C/C + + interface (header file #include) sqlite3_open() sqlite3_close() sqlite3_exec() Callback function: sqlite3_get_tabl ...

Posted by affordit on Mon, 11 Apr 2022 09:22:29 +0300

Creation of partition table of ORACLE

What is a partition table? Why use partition table? How to create a partition table? If the data in a table in your database meets the following conditions, you should consider creating a partitioned table. 1. There are a lot of data in a table in the database. What are many concepts? Ten thousand? 20000? One hundred thousand or one million? T ...

Posted by Garrett on Mon, 11 Apr 2022 09:20:24 +0300

MySQL gets the Pinyin initials of Chinese characters

1, Function Here is to obtain the Pinyin initial of Chinese characters through function call. DELIMITER $$ CREATE FUNCTION `pinyin`(P_NAME VARCHAR(255)) RETURNS varchar(255) CHARSET utf8 DETERMINISTIC BEGIN DECLARE V_COMPARE VARCHAR(255); DECLARE V_RETURN VARCHAR(255); DECLARE I INT; SET I = 1; SET V_RETURN = ''; #Cir ...

Posted by lou28 on Sat, 09 Apr 2022 05:37:10 +0300

Query table: MySQL

Chapter 06_ multi-table query Multi table query, also known as association query, refers to two or more tables completing the query operation together. Prerequisite: these tables queried together are related (one to one, one to many). There must be an associated field between them. This associated field may or may not have a foreign key. Fo ...

Posted by dansk on Fri, 08 Apr 2022 17:49:16 +0300