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Record the whole process of connecting to SQL Server database in detail environment System: Windows 10 professionalQt version: Qt 5.14.2 [compilation kit MinGW 32]SQL Sever: SQL Sever 2019Programming language: C++ 1, Configuring ODBC data sources 1, Add a new user in SQL Sever Manger 1. Open the MSS Management Studio provided below ...

Document the use of the log4net logging framework in your project: 1. Install Log4net package via Nuget   2. Add configuration files, configure the format of log records, etc. Log4net. The config configuration information is as follows: <?xml version="1.0" encoding="utf-8"?> <log4net> <!--type Indicates what type of ...

Create advanced join This chapter will explain some other join types (including their meaning and usage), and introduce how to use table aliases and aggregation functions for the joined tables. Use table alias Chapter 10( MySQL must know and know -- Chapter 10 creating calculation fields )Describes how to use aliases to reference table colum ...

-DQL operation table record - query [ key ] 7.1 basic query syntax select Field name to query from Table name [where condition] 7.2 simple query 7.2.1 query records of all rows and columns grammar select * form surface Query all the columns in the commodity table select * from product; 7.2.2 query records of specific columns in a t ...

catalogue 1, Prerequisites for database programming 2, Database programming in Java: JDBC 3, How JDBC works 4, Construction of development environment 5, JDBC programming in MySQL 1. Five step process 2. Add information 3. Query information 4. Delete information 5. Modify information 1, Prerequisites for database programming Pro ...

About database operations: 1. Design background: With the development of information technology, computers have entered thousands of households. People's communication has become convenient and convenient for the life of Internet users! In addition, with the rise of excellence, Jingdong, Taobao and other online shopping platforms, online shop ...

Case has two formats: simple case function and case search function. – simple Case function The function of a simple Case expression is to use the expression to determine the return value: select id,name, case sex when '1' then 'male' when '2' then 'female' else 'other' end from student – search Case function: Case function (c ...

Transaction It exists in both SQL server and Mysql It refers to the smallest unit to complete an application processing, which is composed of one or more statements operating on the database. If all operations are successful before submitting a failure, all operations will be cancelled and restored to the previous state. 1. Cases where transac ...

In the process of using the database, the most exposed is the table in the database, which stores all the data in the database. Therefore, the table is the basic information storage structure of SQL Server database system and the most important part of the database. Managing the table naturally manages the database. 1. Data sheet overview & ...

Recently, someone asked this question in the interview. Before that, they had not studied the specific use logic of the joint index, consulted several articles, and came to some conclusions after testing Test environment: SQL Server 2008 R2 The test results are similar to the query mechanism of MySql joint index. We can think that MySql is the ...