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1 problem status At first, we used the simplest offset+limit paging query method. The pseudo code is as follows: List<Student> students = new ArrayList<>(); int limit = n; int offset = 0; do { students = SELECT * FROM [table] WHERE status = [status] AND gradeId = [id] LIMIT [limit] OFFSET [offset]; push(pos); update [table] ...

Centos7 installs MySQL 8 database (yum, the default interpreter is python2.7, don't change Python soft connection) mkdir /data mkdir /data/mysql cd /data/mysql wget https://dev.mysql.com/get/mysql80-community-release-el7-2.noarch.rpm yum -y install mysql80-community-release-el7-2.noarch.rpm yum -y install mysql-community-server If it is ...

catalogue 1, Common data types 2, View database structure 1. Enter database 2. View database information 3. View information about tables in the database 4. Display the structure (field) of the data table III. overview of SQL statements 1. SQL language 2. SQL classification III. DDL 1. Create databases and tables 2. Delete the speci ...

catalogue I Log management of MySQL (1) Log classification of MySQL (2)MySQL log on (3) enter the database to check whether the corresponding log is enabled II MySQL full backup and recovery (1) Importance of data backup (2) Causes of data loss (3) Classification of database backup (4) Common backup methods ① Physical cold standby ② ...

Author: Li PengboAs a member of aikesheng DBA team, he will be transformed and is mainly responsible for MySQL fault handling and SQL audit optimization. Be dedicated to technology and responsible for customers.Source: original contribution*It is produced by aikesheng open source community. The original content cannot be used without authorizat ...

Functions for MySQL Common Functions -- Mathematical operations SELECT ABS(-8) -- absolute value SELECT CEILING(9.4) -- ceil SELECT FLOOR(9.4) -- Rounding Down SELECT RAND() -- Return 0-1 random number SELECT SIGN(-10) -- Judging the sign 0 of a number-0 Negative Return-1 Positive number returns 1 -- String function SELECT CHAR_LENGTH( ...

Load MYSQL database driver The development tool used by the author is IntelliJ IDEA, and other integrated environments have similar principles. Download MYSQL database driver JDBC is java data base connectivity. In order to access the database on the MySQL database server, the application must ensure that the corresponding JDBC-MYSQL driver ...

Methods in the database: DDL: operation database and table 1. Operation database: CRUD 1. C(Create):establish * Create database: * create database Database name; * Create a database, judge that it does not exist, and then create: * create database if not exists Database name; * Create a database and specify a character set ...

Database design 1, Relationship between multiple tables 1. Classification: One to one (understanding): Such as: person and ID cardAnalysis: a person has only one ID card, and one ID card can only correspond to one person One to many (many to one): For example: departments and employeesAnalysis: a department has multiple employees, and ...

Explain use and explanation Explain tool introduction Use the EXPLAIN keyword to simulate the database optimizer to execute SQL statements and analyze the performance bottlenecks of your query statements or structures Add the explain keyword before the select statement. MySQL will set a flag on the query. Executing the query will return the i ...