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We also analyzed the integration of shardingsphere component with spring boot to realize database and table division. Sub database and sub table are mainly used to solve IO problems and slow query caused by massive data. ShardingSphere is an ecosystem composed of a set of open-source distributed database middleware solutions. It is composed of ...

Java JDBC learning JDBC (Java DataBase Connectivity) java database connection ● is a Java API for executing SQL statements, which can provide unified access to a variety of relational databases. It is composed of a group of classes and interfaces written in Java language. With JDBC,java developers only need to write a program once to access di ...

Related sub query -- Related sub query: sub queries cannot be run independently, and external queries must be run before sub queries -- Advantages: simple and powerful -- Disadvantages: difficult to understand -- Query the employee with the highest salary in the Department SELECT deptno,ename,max(sal) from emp GROUP BY deptno -- The state ...

The original content of GreatSQL community cannot be used without authorization. Please contact Xiaobian and indicate the source for reprint.1. Problem descriptionOccasionally encountered gtid during MGR testing_ The executed transaction ID is discontinuous, but it does not affect the normal operation of the database. The phenomenon is as follo ...

I Basic introduction    regular expression describes a string matching rule. Regular expression itself is a string. This string is used to describe and define matching rules to match a series of strings that meet a certain syntactic rule. In development, regular expressions are often used to retrieve and replace text that conf ...

Most of the previous discussions are about MYSQL queries. Now we talk about adding, deleting and modifying. After all, these are several operations commonly used in DML. Now create a table CREATE TABLE test( a INT, b VARCHAR(10), c DATE ) Add data General insertion Adding data is very simple, that is, adding data to the database. This is ...

1, Business Characteristics of transactions Atomicity: a transaction must be an atomic unit of work. All statements in a transaction must be done or none of them.Consistency: keep the data logically "reasonable". When A transfers to B, A must pay less and B must pay moreIsolation: if multiple transactions are executed concurrent ...

1. Introduction to Orch Orchestrator (orch): MySQL high availability and replication topology management tool written by go, which supports the adjustment of replication topology, automatic failover and manual master-slave switching. The back-end database uses MySQL or SQLite to store metadata, and provides a Web interface to display the topol ...

Preparation before configuration 1. Prepare 2 mysql environments 2. Interworking between two mysql networks First step Configure mysql configuration file [my.cnf] | [my.ini] The [master] configuration is as follows: [mysqld] server-id = 1 # Node ID to ensure uniqueness log config log-bin = mysql-bin #Enable the binlog function of ...

Delayed loading mechanism of mybatis The meaning of delayed loading: relevant operations will be carried out only when it is used Mybatis supports delayed loading of association Association objects and Collection association collection objects Difference: association usage scenario is a one-to-one association query, and collection is a one t ...