Tag：Sentence
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Time：2021-10-25
objective By understanding the relevant configuration of binlog log, you can simply master the data recovery operation of database through binlog; MySQL log file Any mature software will have a mature log system. When there is a problem with the software, these logs are the treasure house to query the source of the problem. Similarly, […]
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Time：2021-10-25
1、 Transaction classification Transaction is a program execution unit that accesses and updates various data items in the database. Transaction will convert the database from one consistent state to another consistent state. This is the purpose of transaction and one of the important characteristics that distinguish the transaction model from the file system. Transactions in […]
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Time：2021-10-24
Basics: 1. Concept: a persistence layer framework in Java.2. Features and advantages:(1) Java code and SQL code are completely separated.(2) Good support for complex object mapping (input mapping, output mapping)(3) Using dynamic SQL, you can prevent SQL injection.3. Principle:(1) Create the mybatis-config.xml configuration file(2) Create sqlsessionfactory(3) Write the entity class corresponding to the database table(4) […]
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Time：2021-10-24
Time: Wednesday, September 13, 2017Note: some of the contents of this article are taken from the book “complete collection of Linux command line and shell script programming”, and the copyright belongs to the original author. Summary of Chapter 13 of Linux command line and shell script programming (Third Edition) Chapter 13: more structured commands Contents […]
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Time：2021-10-23
Mysqldump is a database logical backup program. It is usually used to back up or restore one or more MySQL databases. In addition, it can also transfer the databases to other MySQL servers. Next, Liang Xu Xiaobian willLinux mysqldump commandI hope it will be helpful to you. When using mysldump to back up database tables, […]
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Time：2021-10-23
1、 Business 1. What is a transaction A transaction consists of one or moreSQLThe logical execution unit composed of statements can be compared to a container, which contains a pile ofSQLStatements, either all of which are executed successfully or none of which can be executed successfully（Atomicity) 2. Why use transactions When performing a series of […]
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Time：2021-10-23
1、 Mybatis complete example Here, I’ll use an entry-level example to demonstrate how mybatis works. Note: the principles and source code in the later chapters of this article will also be explained based on this example.Full sample source address 1.1. Database preparation In this example, crud operation is required for a user table. The data […]
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Time：2021-10-22
Field type The difference between int (5) and int (10) Clickable blogProgram ape grocery storeint(5) Andint(11)The characters in the parentheses after represent the display width. The display width of the integer column has nothing to do with the number of characters MySQL needs to display the value of the column, and has nothing to do […]
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Time：2021-10-22
Go language basic grammar notes Recently, I was learning the basic grammar of go language. The learning course is a tour of go. This paper records the most basic knowledge of go language, including the basic program code structure, the definition of variables and functions, and the definition of basic constants. An example of the […]
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Time：2021-10-21
background“A peak forms on the side of a mountain, and the distance is different. You don’t know the true face of Lushan Mountain, but you only live in this mountain.” you can reach “thousands of mountains in the same month, all households in spring. Thousands of rivers have water, thousands of rivers have moon, and […]
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Time：2021-10-21
Today, I’d like to introduce a difference between the update statement in MySQL database and the implementation of SQL standard (and other databases). If we don’t pay attention to this problem, it may lead to unexpected results. Let’s first create a simple example table: CREATE TABLE t1( id int, col1 int, col2 int ); INSERT […]
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Time：2021-10-20
1. Understand SQL A database is a container (usually a file or group of files) that holds organized data. A table is a structured list of a particular type of data. Schema information about the layout and characteristics of databases and tables. Column a field in a table. All tables consist of one or more […]
