Developing with Databend using Golang

Databend offers a driver (databend-go) written in Golang, which facilitates the development of applications using the Golang programming language and establishes connectivity with Databend.

For installation instructions, examples, and the source code, see the GitHub databend-go repo.

In the following tutorial, you'll learn how to utilize the driver databend-go to develop your applications. The tutorial will walk you through creating a SQL user in Databend and then writing Golang code to create a table, insert data, and perform data queries.

Tutorial: Developing with Databend using Golang

Before you start, make sure you have successfully installed a local Databend. For detailed instructions, see Local and Docker Deployments.

Step 1. Prepare a SQL User Account

To connect your program to Databend and execute SQL operations, you must provide a SQL user account with appropriate privileges in your code. Create one in Databend if needed, and ensure that the SQL user has only the necessary privileges for security.

This tutorial uses a SQL user named 'user1' with password 'abc123' as an example. As the program will write data into Databend, the user needs ALL privileges. For how to manage SQL users and their privileges, see https://databend.rs/doc/reference/sql/ddl/user.

CREATE USER user1 IDENTIFIED BY 'abc123';
GRANT ALL on *.* TO user1;

Step 2. Write a Golang Program

In this step, you'll create a simple Golang program that communicates with Databend. The program will involve tasks such as creating a table, inserting data, and executing data queries.

1. Copy and paste the following code to the file main.go:

note

The value of hostname in the code below must align with your HTTP handler settings for Databend query service.

main.go

package main

import (
    "database/sql"
    "fmt"
    "log"

    _ "github.com/databendcloud/databend-go"
)

const (
    username = "user1"
    password = "abc123"
    hostname = "127.0.0.1:8000"
)

type Book struct {
    Title  string
    Author string
    Date   string
}

func dsn() string {
    return fmt.Sprintf("http://%s:%s@%s", username, password, hostname)
}

func main() {
    db, err := sql.Open("databend", dsn())

    if err != nil {
        log.Fatal(err)
    }
    defer db.Close()

    err = db.Ping()
    if err != nil {
        log.Fatal(err)
    }
    log.Println("Connected")

    // Create db if do not exist
    dbSql := "CREATE DATABASE IF NOT EXISTS book_db"
    _, err = db.Exec(dbSql)
    if err != nil {
        log.Fatal(err)
    }
    log.Println("Create database book_db success")

    // Use book_db database
    _, err = db.Exec("USE book_db")
    if err != nil {
        log.Fatal(err)
    }

    // Create table.
    sql := "create table if not exists books(title VARCHAR, author VARCHAR, date VARCHAR)"
    _, err = db.Exec(sql)
    if err != nil {
        log.Fatal(err)
    }
    log.Println("Create table: books")

    // Insert 1 row.
    _, err = db.Exec("INSERT INTO books VALUES(?, ?, ?)", "mybook", "author", "2022")
    if err != nil {
        log.Fatal(err)
    }
    log.Println("Insert 1 row")

    // Select.
    res, err := db.Query("SELECT * FROM books")
    if err != nil {
        log.Fatal(err)
    }

    for res.Next() {
        var book Book
        err := res.Scan(&book.Title, &book.Author, &book.Date)
        if err != nil {
            log.Fatal(err)
        }

        log.Printf("Select:%v", book)
    }
    db.Exec("drop table books")
    db.Exec("drop database book_db")
}

2. Install dependencies.

go mod init databend-golang

go.mod

module databend-golang

go 1.20

require github.com/databendcloud/databend-go v0.3.10

require (
    github.com/BurntSushi/toml v1.2.1 // indirect
    github.com/avast/retry-go v3.0.0+incompatible // indirect
    github.com/google/uuid v1.3.0 // indirect
    github.com/pkg/errors v0.9.1 // indirect
    github.com/sirupsen/logrus v1.9.0 // indirect
    golang.org/x/sys v0.5.0 // indirect
)

3. Run the program.

go run main.go

Outputs

2023/02/24 23:57:31 Connected
2023/02/24 23:57:31 Create database book_db success
2023/02/24 23:57:31 Create table: books
2023/02/24 23:57:31 Insert 1 row
2023/02/24 23:57:31 Select:{mybook author 2022}