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In the student information management system, firstly, the administrator will add, delete, modify, search and import teacher information, and then the teacher interface will log in to different teacher categories. The counselor teacher is responsible for adding, deleting and searching the relevant information of students, the educational adm ...

1. Variables In the stored procedures and functions of MySQL database, variables can be used to store the intermediate result data of query or calculation, or output the final result data. In MySQL database, variables are divided into system variables and user-defined variables. 1.1 system variables 1.1.1 classification of system variables Vari ...

1, Introduction At present, MHA (Master High Availability) is a relatively mature solution for MySQL high availability. It is developed by Japan DeNA company youshimaton (now working for Facebook company). It is an excellent set of high availability software for failover and master-slave improvement in MySQL high availability environment ...

Subquery refers to a query in which one query statement is nested inside another query statement. This feature has been introduced since MySQL 4.1. The use of SQL sub query greatly enhances the ability of SELECT query, because many times the query needs to obtain data from the result set, or calculate a data result from the same table, and then ...

1. Prepare table information 2.MySQL advanced statement 2.1 alias Field alias, table alias Syntax: SELECT "table alias" "Field 1" [AS] "field alias" FROM "table name" [AS] "table alias"; Example: select A.age 'Age' from REGION A order by Age asc; 2.2 sub query: join table Insert ...

Distributed cluster architecture scenario optimization solution: distributed ID solution Distributed ID solution Why do I need a distributed ID (globally unique ID in a distributed cluster environment) 1. UUID (available) UUID refers to universal unique identifier, which is a universal unique identifier when translated into Chinese The o ...

1, Basic knowledge 1.1. A data storage procedure   the first step in processing data when storing data. Only by storing the data correctly can we process and analyze it effectively. In mysql, a complete data storage process has four steps: creating a database, confirming fields, creating a data table, and inserting data. From the perspecti ...

The real power of MyBatis lies in its statement mapping, which is its magic. Because of its extraordinary power, the XML file of the mapper is relatively simple. If you compare it with JDBC code with the same function, you will immediately find that nearly 95% of the code is saved. MyBatis is committed to reducing the use cost and enabling user ...

Log management MySQL log default save location /usr/local/mysql/data Error log It is used to record the error messages that occur when MySQL is started, stopped or running. It is enabled by default log-error=/usr/local/mysql/data/mysql_error.log #Specify the save location and file name of the log General query log It is used ...

Database foundation What is a database A database is a warehouse for storing and managing secretaries The database we often say is: relational data management system, that is, database server Java and database Application: request data from the database and display the results Database server: storing data 1, SQL overview 1. What is SQL ...