Programmer Group

Integrate Mybatis <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>2.1.2</version> </dependency> Steps: 1) . configure data source related properties (see Druid in the previous section) 2) . creating tables for data ...

I often use SQL in my work, which has annoying subtle differences and limitations, but after all, it is the cornerstone of the data industry.Therefore, SQL is indispensable to every data worker.Being proficient in SQL means a lot. SQL is good, but how can you just be satisfied with "good"?Why not proceed further with SQL? Statements c ...

Business description: table A is the detailed statement of table B. now it is required that table B has millions of records. Insert the relevant records of table B in table A. Preparation: oracle database, database tool pl\sql, stored procedures written in the package. Implementation ideas: 3.1 get the total data volu ...

In fact, it is not difficult to configure spring boot jap+mybatis druid with multiple data sources The key cannot be confused. Otherwise, after the configuration is completed, the connection of the druid data source may explode some strange errors, such as connection timeout, connection unavailable, etc Reference resources: Create a DataSour ...

Preface In the previous article, I briefly introduced Linq's entry-level usage. This article tries to explain some more in-depth usage methods. Unlike the previous article, I will first introduce the support methods in Linq, and then write them in the form of method chain and SQL like, guided by the actual requirements. Introduction to pre conc ...

(any SQL not explicitly indicated in this article is executed on the coordination node.) Work node mydb1=# SELECT * FROM master_get_active_worker_nodes(); node_name | node_port ---------------+----------- 192.168.7.131 | 5432 192.168.7.135 | 5432 192.168.7.136 | 5432 192.168.7.137 | 5432 192.168 ...

JDBC JDBC(Java Database connectivity) is a Java API for executing SQL statements Can provide unified access to a variety of relational databases Java database connection specification (a set of interfaces) There are four core classes of JDBC: DriverManager create connection Connection connection class S ...

Spring provides a powerful template class -- JDBC template to simplify JDBC operations. The data source DataSource object and the template JDBC template object can be defined in the configuration file in the form of Bean, giving full play to the power of dependency injection.   Case: use JDBC template to query all books 1. Introduce jar package ...

1. Create user table CREATE TABLE user100w( id INT NOT NULL AUTO_INCREMENT, first_name VARCHAR(10) NOT NULL, last_name VARCHAR(10) NOT NULL, sex VARCHAR(5) NOT NULL, score INT NOT NULL, copy_id INT NOT NULL, PRIMARY KEY (`id`) ); 2. Create stored procedure DROP PROCEDURE IF EXISTS add_user; DELIMITER / ...

Guide: is it very interesting to be able to carry out a single line or lines of SQL files? Today, let's introduce this interesting Library -- dotsql. Background introduction dotsql is not an ORM or a builder of SQL query statements, but a tool that can carry out several lines in an SQL file, very similar to the reading of ini configuration fi ...