在 Ubuntu 使用SQL Server创建 Go 应用程序
一、设置环境
在 Ubuntu 机器上安装 SQL Server 2017和安装运行 GoLang 所需的依赖项。
1.1、安装 SQL Server
为了确保 SQL Server 的最佳性能，计算机应至少具有 4 GB 的内存。
（1）注册 Microsoft Linux 存储库并添加其密钥。
curl https://packages.microsoft.com/keys/microsoft.asc | sudo apt-key add -
curl https://packages.microsoft.com/config/ubuntu/16.04/mssql-server-2017.list | sudo tee /etc/apt/sources.list.d/mssql-server-2017.list
（2）安装 SQL Server。
sudo apt-get update
sudo apt-get install mssql-server
执行结果：
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
mssql-server
...
Unpacking mssql-server ...
Setting up mssql-server ...
（3）设置 SQL Server。
sudo /opt/mssql/bin/mssql-conf setup
执行结果：
Microsoft(R) SQL Server(R) Setup
To abort setup at anytime, press Ctrl-C.
The license terms for this product can be downloaded from http://go.microsoft.com/fwlink/?LinkId=746388 and
found in /usr/share/doc/mssql-server/LICENSE.TXT.
Do you accept the license terms? If so, please type YES:
Please enter a password for the system administrator (SA) account:
Please confirm the password for the system administrator (SA) account:
1.2、安装 GoLang
如果您的机器上已经安装了 Go，请跳过此步骤。
（1）下载安装。
curl -O https://storage.googleapis.com/golang/go1.8.linux-amd64.tar.gz
tar xvf go1.8.linux-amd64.tar.gz
sudo chown -R root:root ./go
sudo mv go /usr/local
（2）将这两行添加到 ~/.profile 文件中。
export GOPATH=$HOME/work
export PATH=$PATH:/usr/local/go/bin:$GOPATH/bin
1.3、安装 ODBC 驱动程序和 SQL 命令行实用工具 SQL 服务器
SQLCMD 是一个命令行工具，能够连接到 SQL Server 并运行查询。
（1）下载适用于操作系统版本的软件包。
sudo su
curl https://packages.microsoft.com/keys/microsoft.asc | apt-key add -
#Download appropriate package for the OS version
#Choose only ONE of the following, corresponding to your OS version
#Ubuntu 16.04
curl https://packages.microsoft.com/config/ubuntu/16.04/prod.list > /etc/apt/sources.list.d/mssql-release.list
#Ubuntu 18.04
curl https://packages.microsoft.com/config/ubuntu/18.04/prod.list > /etc/apt/sources.list.d/mssql-release.list
#Ubuntu 19.10
curl https://packages.microsoft.com/config/ubuntu/19.10/prod.list > /etc/apt/sources.list.d/mssql-release.list
exit
sudo apt-get update
sudo ACCEPT_EULA=Y apt-get install msodbcsql17
# optional: for bcp and sqlcmd
sudo ACCEPT_EULA=Y apt-get install mssql-tools
echo 'export PATH="$PATH:/opt/mssql-tools/bin"' >> ~/.bash_profile
echo 'export PATH="$PATH:/opt/mssql-tools/bin"' >> ~/.bashrc
source ~/.bashrc
# optional: for unixODBC development headers
sudo apt-get install unixodbc-dev
（2）安装 SQLCMD 后，可以使用以下命令连接到 SQL Server：
sqlcmd -S localhost -U sa -P yourpassword
1> # You're connected! Type your T-SQL statements here. Use the keyword 'GO' to execute each batch of statements.
（3）测试数据库。结果将打印到标准输出。
sqlcmd -S localhost -U sa -P yourpassword -Q "SELECT @@VERSION"
--------------------------------------------------------
Microsoft SQL Server vNext (CTP2.0) - 14.0.500.272 (X64)
Apr 2 2023 11:44:40
Copyright (c) Microsoft Corporation
on Linux (Ubuntu 16.04)
1 rows(s) returned
Executed in 1 ns
至此，已成功在 Ubuntu 机器上安装 SQL Server 命令行实用程序，已经在 Ubuntu 计算机上成功安装并设置 GoLang 和 mssql-tools。现在拥有开始使用 SQL Server 编写 Go 应用程序所需的一切。
二、使用 SQL 服务器创建 Go 应用程序
安装 SQL Server 和 GoLang 后，现在可以继续创建新的 Go 项目。在这里，将探讨三个简单的应用程序。其中一个将连接并打印数据库服务器的SQL Server版本，另一个将执行基本的插入，更新，删除和选择操作，第三个将使用GORM，一种流行的对象关系映射（ORM）框架，用于Go执行相同的操作。
2.1、创建连接到 SQL Server 并执行查询的 Go 应用
（1）创建新的项目目录并安装 Go 依赖项。
cd ~/
#Create Project Directory
mkdir SqlServerSample
cd SqlServerSample
# Get and install the SQL Server driver for Go
go get github.com/denisenkom/go-mssqldb
go install github.com/denisenkom/go-mssqldb
（2）通过使用 sqlcmd 连接到 SQL Server 并执行以下命令，创建将用于本教程其余部分的数据库。不要忘记使用自己的用户名和密码更新用户名和密码。
sqlcmd -S 127.0.0.1 -U sa -P <你的> -Q "CREATE DATABASE SampleDB;"
（3）创建一个连接到 SQL Server 的简单 Go 应用。
在 SqlServerSample 文件夹中创建一个名为 connect.go 的文件。将以下内容复制并粘贴到文件中。不要忘记使用自己的用户名和密码更新用户名和密码。
此示例使用 GoLang 上下文方法来确保存在与数据库服务器的活动连接。
package main
import (
_ "github.com/denisenkom/go-mssqldb"
"database/sql"
"context"
"log"
"fmt"
)
// Replace with your own connection parameters
var server = "localhost"
var port = 1433
var user = "sa"
var password = "xxxxxx"
var db *sql.DB
func main() {
var err error
// Create connection string
connString := fmt.Sprintf("server=%s;user id=%s;password=%s;port=%d",
server, user, password, port)
// Create connection pool
db, err = sql.Open("sqlserver", connString)
if err != nil {
log.Fatal("Error creating connection pool: " + err.Error())
}
log.Printf("Connected!\n")
// Close the database connection pool after program executes
defer db.Close()
SelectVersion()
}
// Gets and prints SQL Server version
func SelectVersion(){
// Use background context
ctx := context.Background()
// Ping database to see if it's still alive.
// Important for handling network issues and long queries.
err := db.PingContext(ctx)
if err != nil {
log.Fatal("Error pinging database: " + err.Error())
}
var result string
// Run query and scan for result
err = db.QueryRowContext(ctx, "SELECT @@version").Scan(&result)
if err != nil {
log.Fatal("Scan failed:", err.Error())
}
fmt.Printf("%s\n", result)
}
（4）运行应用程序。
go run connect.go
执行结果：
Connected!
Microsoft SQL Server 2017 (CTP2.1) - 14.0.600.250 (X64)
Apr 2 2017 12:21:23
Copyright (C) 2017 Microsoft Corporation. All rights reserved.
Developer Edition (64-bit) on Linux (Ubuntu 16.04.2 LTS)
（5）在 SqlServerSample 文件夹中创建一个名为 CreateTestData 的文件.sql。将以下 T-SQL 代码复制并粘贴到其中。这将创建一个架构、表并插入几行。
CREATE SCHEMA TestSchema;
GO
CREATE TABLE TestSchema.Employees (
Id INT IDENTITY(1,1) NOT NULL PRIMARY KEY,
Name NVARCHAR(50),
Location NVARCHAR(50)
);
GO
INSERT INTO TestSchema.Employees (Name, Location) VALUES
(N'Jared', N'Australia'),
(N'Nikita', N'India'),
(N'Tom', N'Germany');
GO
SELECT * FROM TestSchema.Employees;
GO
（6）使用 sqlcmd 连接到数据库并运行 SQL 脚本以创建架构、表并插入一些行。
sqlcmd -S 127.0.0.1 -U sa -P <你的> -d SampleDB -i ./CreateTestData.sql
执行结果：
CREATE SCHEMA TestSchema;
Executed in 0 ms
CREATE TABLE TestSchema.Employees (
Id INT IDENTITY(1,1) NOT NULL PRIMARY KEY,
Name NVARCHAR(50),
Location NVARCHAR(50)
);
Executed in 0 ms
INSERT INTO TestSchema.Employees (Name, Location) VALUES
(N'Jared', N'Australia'),
(N'Nikita', N'India'),
(N'Tom', N'Germany');
Executed in 0 ms
SELECT * FROM TestSchema.Employees;
Id Name Location
-- ------ ---------
1 Jared Australia
2 Nikita India
3 Tom Germany
3 row(s) returned
Executed in 1 ms
（7）在 SqlServerSample 文件夹中创建一个名为 crud.go 的新文件。将以下代码复制并粘贴到其中。这将插入、更新、删除和读取几行。
package main
import (
_ "github.com/denisenkom/go-mssqldb"
"database/sql"
"context"
"log"
"fmt"
"errors"
)
var db *sql.DB
var server = "localhost"
var port = 1433
var user = "sa"
var password = "你的"
var database = "SampleDB"
func main() {
// Build connection string
connString := fmt.Sprintf("server=%s;user id=%s;password=%s;port=%d;database=%s;",
server, user, password, port, database)
var err error
// Create connection pool
db, err = sql.Open("sqlserver", connString)
if err != nil {
log.Fatal("Error creating connection pool: ", err.Error())
}
ctx := context.Background()
err = db.PingContext(ctx)
if err != nil {
log.Fatal(err.Error())
}
fmt.Printf("Connected!\n")
// Create employee
createID, err := CreateEmployee("Jake", "United States")
if err != nil {
log.Fatal("Error creating Employee: ", err.Error())
}
fmt.Printf("Inserted ID: %d successfully.\n", createID)
// Read employees
count, err := ReadEmployees()
if err != nil {
log.Fatal("Error reading Employees: ", err.Error())
}
fmt.Printf("Read %d row(s) successfully.\n", count)
// Update from database
updatedRows, err := UpdateEmployee("Jake", "Poland")
if err != nil {
log.Fatal("Error updating Employee: ", err.Error())
}
fmt.Printf("Updated %d row(s) successfully.\n", updatedRows)
// Delete from database
deletedRows, err := DeleteEmployee("Jake")
if err != nil {
log.Fatal("Error deleting Employee: ", err.Error())
}
fmt.Printf("Deleted %d row(s) successfully.\n", deletedRows)
}
// CreateEmployee inserts an employee record
func CreateEmployee(name string, location string) (int64, error) {
ctx := context.Background()
var err error
if db == nil {
err = errors.New("CreateEmployee: db is null")
return -1, err
}
// Check if database is alive.
err = db.PingContext(ctx)
if err != nil {
return -1, err
}
tsql := "INSERT INTO TestSchema.Employees (Name, Location) VALUES (@Name, @Location); select convert(bigint, SCOPE_IDENTITY());"
stmt, err := db.Prepare(tsql)
if err != nil {
return -1, err
}
defer stmt.Close()
row := stmt.QueryRowContext(
ctx,
sql.Named("Name", name),
sql.Named("Location", location))
var newID int64
err = row.Scan(&newID)
if err != nil {
return -1, err
}
return newID, nil
}
// ReadEmployees reads all employee records
func ReadEmployees() (int, error) {
ctx := context.Background()
// Check if database is alive.
err := db.PingContext(ctx)
if err != nil {
return -1, err
}
tsql := fmt.Sprintf("SELECT Id, Name, Location FROM TestSchema.Employees;")
// Execute query
rows, err := db.QueryContext(ctx, tsql)
if err != nil {
return -1, err
}
defer rows.Close()
var count int
// Iterate through the result set.
for rows.Next() {
var name, location string
var id int
// Get values from row.
err := rows.Scan(&id, &name, &location)
if err != nil {
return -1, err
}
fmt.Printf("ID: %d, Name: %s, Location: %s\n", id, name, location)
count++
}
return count, nil
}
// UpdateEmployee updates an employee's information
func UpdateEmployee(name string, location string) (int64, error) {
ctx := context.Background()
// Check if database is alive.
err := db.PingContext(ctx)
if err != nil {
return -1, err
}
tsql := fmt.Sprintf("UPDATE TestSchema.Employees SET Location = @Location WHERE Name = @Name")
// Execute non-query with named parameters
result, err := db.ExecContext(
ctx,
tsql,
sql.Named("Location", location),
sql.Named("Name", name))
if err != nil {
return -1, err
}
return result.RowsAffected()
}
// DeleteEmployee deletes an employee from the database
func DeleteEmployee(name string) (int64, error) {
ctx := context.Background()
// Check if database is alive.
err := db.PingContext(ctx)
if err != nil {
return -1, err
}
tsql := fmt.Sprintf("DELETE FROM TestSchema.Employees WHERE Name = @Name;")
// Execute non-query with named parameters
result, err := db.ExecContext(ctx, tsql, sql.Named("Name", name))
if err != nil {
return -1, err
}
return result.RowsAffected()
}
（8）运行 crud.go 应用以查看结果。
go run crud.go
执行结果：
Connected!
Inserted ID: 4 successfully.
ID: 1, Name: Jared, Location: Australia
ID: 2, Name: Nikita, Location: India
ID: 3, Name: Tom, Location: Germany
ID: 4, Name: Jake, Location: United States
Read 4 row(s) successfully.
Updated 1 row(s) successfully.
Deleted 1 row(s) successfully.
2.2、创建一个使用 GORM 连接到 SQL Server 的 Go 应用程序
（1）创建应用目录并初始化 Go 依赖项。
cd ~/
mkdir SqlServerGormSample
cd SqlServerGormSample
# Get and install the SQL Server driver for Go
go get github.com/denisenkom/go-mssqldb
go install github.com/denisenkom/go-mssqldb
（2）将以下内容粘贴到名为orm.go的文件中。确保将密码变量替换为您自己的变量。
package main
import (
"fmt"
"github.com/jinzhu/gorm"
_ "github.com/jinzhu/gorm/dialects/mssql"
"log"
)
var server = "localhost"
var port = 1433
var user = "sa"
var password = "你的"
var database = "SampleDB"
// Define a User model struct
type User struct {
gorm.Model
FirstName string
LastName string
}
// Define a Task model struct
type Task struct {
gorm.Model
Title string
DueDate string
IsComplete bool
UserID uint
}
// Read and print all the tasks
func ReadAllTasks(db *gorm.DB){
var users []User
var tasks []Task
db.Find(&users)
for _, user := range users{
db.Model(&user).Related(&tasks)
fmt.Printf("%s %s's tasks:\n", user.FirstName, user.LastName)
for _, task := range tasks {
fmt.Printf("Title: %s\nDueDate: %s\nIsComplete:%t\n\n",
task.Title, task.DueDate, task.IsComplete)
}
}
}
// Update a task based on a user
func UpdateSomeonesTask(db *gorm.DB, userId int){
var task Task
db.Where("user_id = ?", userId).First(&task).Update("Title", "Buy donuts for Luis")
fmt.Printf("Title: %s\nDueDate: %s\nIsComplete:%t\n\n",
task.Title, task.DueDate, task.IsComplete)
}
// Delete all the tasks for a user
func DeleteSomeonesTasks(db *gorm.DB, userId int){
db.Where("user_id = ?", userId).Delete(&Task{
})
fmt.Printf("Deleted all tasks for user %d", userId)
}
func main() {
connectionString := fmt.Sprintf("server=%s;user id=%s;password=%s;port=%d;database=%s",
server, user, password, port, database)
db, err := gorm.Open("mssql", connectionString)
if err != nil {
log.Fatal("Failed to create connection pool. Error: " + err.Error())
}
gorm.DefaultCallback.Create().Remove("mssql:set_identity_insert")
defer db.Close()
fmt.Println("Migrating models...")
db.AutoMigrate(&User{
})
db.AutoMigrate(&Task{
})
// Create awesome Users
fmt.Println("Creating awesome users...")
db.Create(&User{
FirstName: "Andrea", LastName: "Lam"}) //UserID: 1
db.Create(&User{
FirstName: "Meet", LastName: "Bhagdev"}) //UserID: 2
db.Create(&User{
FirstName: "Luis", LastName: "Bosquez"}) //UserID: 3
// Create appropriate Tasks for each user
fmt.Println("Creating new appropriate tasks...")
db.Create(&Task{
Title: "Do laundry", DueDate: "2017-03-30", IsComplete: false, UserID: 1})
db.Create(&Task{
Title: "Mow the lawn", DueDate: "2017-03-30", IsComplete: false, UserID: 2})
db.Create(&Task{
Title: "Do more laundry", DueDate: "2017-03-30", IsComplete: false, UserID: 3})
db.Create(&Task{
Title: "Watch TV", DueDate: "2017-03-30", IsComplete: false, UserID: 3})
// Read
fmt.Println("\nReading all the tasks...")
ReadAllTasks(db)
// Update - update Task title to something more appropriate
fmt.Println("Updating Andrea's task...")
UpdateSomeonesTask(db, 1)
// Delete - delete Luis's task
DeleteSomeonesTasks(db, 3)
}
（3）运行 orm.go 应用。
go run orm.go
执行结果：
[info] removing callback `mssql:set_identity_insert` from C:/Projects/golang-experiments/tutorials/orm.go:70
Migrating models...
Creating awesome users...
Creating new appropriate tasks...
Reading all the tasks...
Andrea Lam's tasks:
Title: Do laundry
DueDate: 2017-03-30
IsComplete:false
Meet Bhagdev's tasks:
Title: Mow the lawn
DueDate: 2017-03-30
IsComplete:false
Luis Bosquez's tasks:
Title: Do more laundry
DueDate: 2017-03-30
IsComplete:false
Title: Watch TV
DueDate: 2017-03-30
IsComplete:false
Updating Andrea's task...
Title: Buy donuts for Luis
DueDate: 2017-03-30
IsComplete:false
Deleted all tasks for user 3
三、让 Go 应用的速度提高 100 倍
已了解基础知识，接下来可以了解如何使用 SQL Server 改进应用。通过列存储索引的简单示例，以及它们如何提高数据处理速度。与传统行存储索引相比，列存储索引在分析工作负荷上可实现高达 100 倍的性能，并将数据压缩提高多达 10 倍。
3.1、使用 sqlcmd 创建一个包含 5 万个的新表
（1）切换到主目录并为项目创建一个文件夹。
cd ~/
mkdir SqlServerColumnstoreSample
cd SqlServerColumnstoreSample
（2）在 SqlServerColumnstoreSample 文件夹中创建一个名为 CreateSampleTable 的新文件.sql文件。将下面的 T-SQL 代码粘贴到新的 SQL 文件中。保存并关闭文件。
WITH a AS (SELECT * FROM (VALUES(1),(2),(3),(4),(5),(6),(7),(8),(9),(10)) AS a(a))
SELECT TOP(5000000)
ROW_NUMBER() OVER (ORDER BY a.a) AS OrderItemId
,a.a + b.a + c.a + d.a + e.a + f.a + g.a + h.a AS OrderId
,a.a * 10 AS Price
,CONCAT(a.a, N' ', b.a, N' ', c.a, N' ', d.a, N' ', e.a, N' ', f.a, N' ', g.a, N' ', h.a) AS ProductName
INTO Table_with_5M_rows
FROM a, a AS b, a AS c, a AS d, a AS e, a AS f, a AS g, a AS h;
（3）使用 sqlcmd 连接到数据库并运行 SQL 脚本以创建包含 5 万行的表。这可能需要几分钟才能运行。
sqlcmd -S 127.0.0.1 -U sa -P <你的> -d SampleDB -i ./CreateSampleTable.sql
3.2、创建一个 Go 应用程序，用于查询此表并测量所花费的时间
（1）在项目文件夹中，初始化 Go 依赖项。
go get github.com/denisenkom/go-mssqldb
go install github.com/denisenkom/go-mssqldb
（2）在您的文件夹中创建一个名为 columnstore.go 的文件。
package main
import (
_ "github.com/denisenkom/go-mssqldb"
"database/sql"
"context"
"log"
"fmt"
"time"
)
var server = "localhost"
var port = 1433
var user = "sa"
var password = "你的"
var database = "SampleDB"
var db *sql.DB
// Delete an employee from database
func ExecuteAggregateStatement(db *sql.DB) {
ctx := context.Background()
// Ping database to see if it's still alive.
// Important for handling network issues and long queries.
err := db.PingContext(ctx)
if err != nil {
log.Fatal("Error pinging database: " + err.Error())
}
var result string
// Execute long non-query to aggregate rows
err = db.QueryRowContext(ctx, "SELECT SUM(Price) as sum FROM Table_with_5M_rows").Scan(&result)
if err != nil {
log.Fatal("Error executing query: " + err.Error())
}
fmt.Printf("Sum: %s\n", result)
}
func main() {
// Connect to database
connString := fmt.Sprintf("server=%s;user id=%s;password=%s;port=%d;database=%s;",
server, user, password, port, database)
var err error
// Create connection pool
db, err = sql.Open("sqlserver", connString)
if err != nil {
log.Fatal("Open connection failed:", err.Error())
}
fmt.Printf("Connected!\n")
defer db.Close()
t1 := time.Now()
fmt.Printf("Start time: %s\n", t1)
ExecuteAggregateStatement(db)
t2 := time.Since(t1)
fmt.Printf("The query took: %s\n", t2)
}
3.3、测量运行查询所需的时间
从终端运行 Go 应用。
go run columnstore.go
执行结果：
Connected!
Start time: 2023-04-02 15:33:50.0340976 -0700 PDT
Sum: 50000000
The query took: 601.7463ms
3.4、使用 SQLCMD 向表中添加列存储索引
运行以下命令以在表上创建列存储索引：
sqlcmd -S localhost -U sa -P <你的> -d SampleDB -Q "CREATE CLUSTERED COLUMNSTORE INDEX Columnstoreindex ON Table_with_5M_rows;"
3.5、重新运行 columnstore.go 脚本，并注意这次完成查询所花费的时间
go run columnstore.go
Connected!
Start time: 2017-06-05 16:35:02.5409285 -0700 PDT
Sum: 50000000
The query took: 86.9826ms
总结
- 使用列存储索引使 Go 应用更快。
- 参考文档。
