In modern software engineering, the skills required to build efficient and reliable server applications are in high demand. Among them, using Go language to call relational database is an indispensable foundation. In this article, we will use the standard packages in the Go language to query and insert MySQL data.
What is MySQL
MySQL is a relational database management system widely used in Internet infrastructure, developed under the sponsorship of Oracle Corporation. It supports multiple operating systems and programming languages, including the Go language, and has a series of features that support large data integration and high-performance queries.
MySQL data is based on tables. One row of data corresponds to one record, and one column of data corresponds to one field. It uses SQL language to operate on data, the most common SQL operations include SELECT, INSERT, UPDATE, DELETE and CREATE TABLE.
MySQL driver in Go language
In Go language, we can use third-party MySQL driver to connect and query MySQL database. However, the GO language standard library already contains the database/sql
package. This package has implemented the standard SQL database interface and can interact with other convenient and popular SQL databases, including MySQL, PostgreSQL and SQLite. wait.
So, before we start building a Go application that queries MySQL, we need to install the MySql driver. You can use the command line command go get -u github.com/go-sql-driver/mysql
for quick installation.
This is because in the Go language, all data access must be done through the SQL.DB
connection. And the purpose of the driver is to implement the interface conventions in the functions of database/sql
.
Establishing a connection
In the Go language, establishing a connection to the MySQL database is based on the connection string. The connection string contains all the parameters required to connect to MySQL. Such as user name, password, host name or IP address, port number and database name, etc.
db, err := sql.Open("mysql", "user:password@tcp(127.0.0.1:3306)/dbname") if err != nil { log.Fatal(err) }
Query data
In Go language, you can use db.Query()
, db.QueryRow()
anddb.Exec()
function queries and operates data in the MySQL database.
db.Query()
The function is used to query multiple records and returns a *sql.Rows
object. db.QueryRow()
The function is used to query a single record and returns a *sql.Row
object, similar to resultset
, but it only returns the first row of records , usually used to query a single unique record. db.Exec()
The function is used to execute non-query SQL statements, such as INSERT, UPDATE, and DELETE, returning a sql.Result
object.
In this example, we use the db.Query()
function to query all records. We will use a simple counter to count the number of records and print each line of data to the console.
rows, err := db.Query("SELECT id, name FROM users") if err != nil { log.Fatal(err) } defer rows.Close() count := 0 for rows.Next() { var id int var name string if err := rows.Scan(&id, &name); err != nil { log.Fatal(err) } fmt.Printf("id=%d, name=%s\n", id, name) count++ } if err := rows.Err(); err != nil { log.Fatal(err) } fmt.Printf("Found %d users\n", count)
The rows.Close()
function must be called after retrieving data to release the database resources associated with *sql.Rows
. At the same time, the rows.Next()
function is used in the code, which returns a Boolean value indicating whether there are more rows that can be processed. In addition, the rows.Scan()
function is used in this example to copy the value of each row record into the id
and name
variables defined in this example. , and then prints each value in the console.
Insert data
We can also use Go language to insert data into the MySQL database. The simplest way is to use the db.Exec()
function . We can pass the insert statement into the db.Exec()
function and it will be executed in MySQL as a SQL statement.
result, err := db.Exec("INSERT INTO users(name, email) VALUES('John Doe', 'johndoe@gmail.com')") if err != nil { log.Fatal(err) } rowsAffected, err := result.RowsAffected() if err != nil { log.Fatal(err) } fmt.Printf("Inserted %d rows into users table\n", rowsAffected)
We can use result.RowsAffected()
to get the number of affected rows in the result set and use this value to print the number of updated data in the console.
Summary
In this article, we introduced the basic query operations of MySQL database using Go language. We learned how to use the standard library database/sql
and third-party MySQL drivers to establish connections and query data. We also learned how to insert data into a MySQL database using the db.Exec()
function. These concepts are an important part of building efficient and reliable server applications in Go and are an essential skill in modern software engineering.
The above is the detailed content of How to operate mysql data in golang. For more information, please follow other related articles on the PHP Chinese website!

go语言有缩进。在go语言中,缩进直接使用gofmt工具格式化即可(gofmt使用tab进行缩进);gofmt工具会以标准样式的缩进和垂直对齐方式对源代码进行格式化,甚至必要情况下注释也会重新格式化。

本篇文章带大家了解一下golang 的几种常用的基本数据类型,如整型,浮点型,字符,字符串,布尔型等,并介绍了一些常用的类型转换操作。

go语言叫go的原因:想表达这门语言的运行速度、开发速度、学习速度(develop)都像gopher一样快。gopher是一种生活在加拿大的小动物,go的吉祥物就是这个小动物,它的中文名叫做囊地鼠,它们最大的特点就是挖洞速度特别快,当然可能不止是挖洞啦。

是,TiDB采用go语言编写。TiDB是一个分布式NewSQL数据库;它支持水平弹性扩展、ACID事务、标准SQL、MySQL语法和MySQL协议,具有数据强一致的高可用特性。TiDB架构中的PD储存了集群的元信息,如key在哪个TiKV节点;PD还负责集群的负载均衡以及数据分片等。PD通过内嵌etcd来支持数据分布和容错;PD采用go语言编写。

在写 Go 的过程中经常对比这两种语言的特性,踩了不少坑,也发现了不少有意思的地方,下面本篇就来聊聊 Go 自带的 HttpClient 的超时机制,希望对大家有所帮助。

go语言需要编译。Go语言是编译型的静态语言,是一门需要编译才能运行的编程语言,也就说Go语言程序在运行之前需要通过编译器生成二进制机器码(二进制的可执行文件),随后二进制文件才能在目标机器上运行。

删除map元素的两种方法:1、使用delete()函数从map中删除指定键值对,语法“delete(map, 键名)”;2、重新创建一个新的map对象,可以清空map中的所有元素,语法“var mapname map[keytype]valuetype”。


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

Dreamweaver Mac version
Visual web development tools

Notepad++7.3.1
Easy-to-use and free code editor

VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft
