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1. Build MySQL master-slave database Refer to another blog post of the authorhttps://blog.csdn.net/weixin_37838921/article/details/104033403 2.MySQL dual machine environment role IP OS/MySQL version master1 192.168.11.10 CentOS7 / MySQL5.7 master2 192.168.11.30 CentOS7 / MySQL5.7 3. MyS ...

  Master-1: 192.169.7.242 Master-2: 192.169.0.197 MySQL version: mysql-5.7 1. Modification and description of MySQL configuration file Modify mysql of the two nodes respectively. Here, modify the configuration file to / etc/my.cnf Modify Master-1 as follows:   # For advice on how to change sett ...

I. Introduction The    StatementHandler is one of the most core interfaces of Mybatis. He has completed the work related to the interaction between Mybatis and database (the interaction between Mybatis and JDBC on Statement). StatementHandler is mainly used for: Create Statement object Bind ...

A dictionary in Python is a collection of key:value pair s.Similar to Map or lookup table s in other languages. The key must be a string, and the value can be any object. Both key and value can use variables. Simple Dictionary student = {'name': 'tony', 'age': 14} print(student ['name']) print(studen ...

1. JDBC principle 1. JDBC API: provides various operation providers, connection statement Preparedstatement resultset; 2. JDBC Driver Manager: manage different data drivers; 3. All kinds of database drivers: database drivers provided by corresponding database manufacturers, which link to directly oper ...

Observe the indicators and check the connection consumption --View session session: select * from v$session where username is not null select username,count(username) from v$session where username is not null group by username --View current connections select count(*) from v$process; --View maximu ...

Inserting data is often required in SQL Server, whether stored procedures or custom functions.When inserting data, many people choose the following INSERT INTO DestinationTable SELECT Column1,Column2,<column3 ,> FROM SourceTable This insertion usually doesn't cause any problems, but when the table fields of the Destinat ...

1: Structure of tree nodes class KprDimension{ private String id; //Current node id of the tree private String name; //Tree node name private String parentId;// Tree node parent id private Integer level; //The node level of the tree, as shown in the figure below, A is 1, B,C is 2 private List<KprDimension> children;// ...

1. Use scenario Both DBMS SQL package and EXECUTE IMMEDIATE in oracle can be used to parse and execute / dynamic SQL statements or PL/SQL blocks created at non runtime. In comparison, EXECUTE IMMEDIATE is relatively simple to use and can meet more common needs. 1.1 basic data CREATE TABLE stu( ID NUMBER(10), xm V ...

MySQL database installation configuration In order to see / operate the database easily and intuitively, Navicat Premium software is generally installed to support multiple databases. There is not much nonsense in the installation process, mainly referring to the following connections, no pit in hand test, which are the main ...