Go语言中常用数据库选择的探索

package main

import (
    "database/sql"
    "fmt"

    _ "github.com/go-sql-driver/mysql"
)

func main() {
    db, err := sql.Open("mysql", "root:password@tcp(localhost:3306)/test")
    if err != nil {
        fmt.Println("Failed to connect to MySQL:", err)
        return
    }
    defer db.Close()

    // 查询数据
    rows, err := db.Query("SELECT * FROM users")
    if err != nil {
        fmt.Println("Failed to execute query:", err)
        return
    }
    defer rows.Close()

    for rows.Next() {
        var id int
        var name string
        err := rows.Scan(&id, &name)
        if err != nil {
            fmt.Println("Failed to scan row:", err)
            return
        }
        fmt.Println("ID:", id, "Name:", name)
    }
    if err := rows.Err(); err != nil {
        fmt.Println("Failed to retrieve data:", err)
        return
    }

    // 插入数据
    result, err := db.Exec("INSERT INTO users (name) VALUES (?)", "John")
    if err != nil {
        fmt.Println("Failed to insert data:", err)
        return
    }
    fmt.Println("Insert ID:", result.LastInsertId())
}

package main

import (
    "database/sql"
    "fmt"

    _ "github.com/lib/pq"
)

func main() {
    db, err := sql.Open("postgres", "user=postgres password=password dbname=mydb sslmode=disable")
    if err != nil {
        fmt.Println("Failed to connect to PostgreSQL:", err)
        return
    }
    defer db.Close()

    // 查询数据
    rows, err := db.Query("SELECT * FROM users")
    if err != nil {
        fmt.Println("Failed to execute query:", err)
        return
    }
    defer rows.Close()

    for rows.Next() {
        var id int
        var name string
        err := rows.Scan(&id, &name)
        if err != nil {
            fmt.Println("Failed to scan row:", err)
            return
        }
        fmt.Println("ID:", id, "Name:", name)
    }
    if err := rows.Err(); err != nil {
        fmt.Println("Failed to retrieve data:", err)
        return
    }

    // 插入数据
    result, err := db.Exec("INSERT INTO users (name) VALUES ($1)", "John")
    if err != nil {
        fmt.Println("Failed to insert data:", err)
        return
    }
    fmt.Println("Insert ID:", result.LastInsertId())
}

package main

import (
    "context"
    "fmt"
    "log"
    "time"

    "go.mongodb.org/mongo-driver/bson"
    "go.mongodb.org/mongo-driver/mongo"
    "go.mongodb.org/mongo-driver/mongo/options"
)

type User struct {
    ID   string
    Name string
}

func main() {
    client, err := mongo.NewClient(options.Client().ApplyURI("mongodb://localhost:27017"))
    if err != nil {
        log.Fatal(err)
    }

    ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
    defer cancel()

    err = client.Connect(ctx)
    if err != nil {
        log.Fatal(err)
    }
    defer client.Disconnect(ctx)

    collection := client.Database("test").Collection("users")

    // 查询数据
    cur, err := collection.Find(ctx, bson.D{})
    if err != nil {
        log.Fatal(err)
    }
    defer cur.Close(ctx)

    for cur.Next(ctx) {
        var user User
        if err := cur.Decode(&user); err != nil {
            log.Fatal(err)
        }
        fmt.Println("ID:", user.ID, "Name:", user.Name)
    }
    if err := cur.Err(); err != nil {
        log.Fatal(err)
    }

    // 插入数据
    user := User{ID: "1", Name: "John"}
    _, err = collection.InsertOne(ctx, user)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("Insert ID:", user.ID)
}