Implementation method of order query function in ordering system developed with Go language

Go language develops the order query function implementation method in the ordering system, which requires specific code examples

In a food ordering system, order query is a very important function one. Users can view their historical orders, as well as the order status and details through the order query function. In this article, we will introduce how to use Go language to develop a simple order query function, as well as the detailed implementation process of the code.

1. Create database model

First, you need to create a database model to store orders. We can use the GORM library to create and manage models. The following is a simple order model:

type Order struct {
    ID       uint   `gorm:"primary_key"`
    UserID   uint   `gorm:"not null"`
    Amount   uint   `gorm:"not null"`
    Status   string `gorm:"not null"`
    CreatedAt time.Time
    UpdatedAt time.Time
}

The above code defines an order model, including the following fields:

• ID: Order ID, using uint type to represent the primary key;
• UserID: The ID of the user to which the order belongs;
• Amount: The total amount of the order, represented by uint type;
• Status: Order status, represented by string type;
• CreatedAt: Order creation time, represented by time.Time type;
• UpdatedAt: Order update time, represented by time.Time type.

2. Create a database connection

Next, we need to create a database connection to operate the order model. We can choose to use a MySQL database, but we need to install the corresponding MySQL driver. The following is an example of a database connection:

import (
    "fmt"
    "github.com/jinzhu/gorm"
    _ "github.com/jinzhu/gorm/dialects/mysql"
)

func ConnectDB() (*gorm.DB, error) {
    db, err := gorm.Open("mysql", "root:@/orders_db?charset=utf8&parseTime=True&loc=Local")
    if err != nil {
        return nil, err
    }
    fmt.Println("Database connection established")
    return db, nil
}

The above code connects to the MySQL database named "orders_db" and returns a pointer to the database, or an error if an error occurs.

3. Create Order Query API

Now, we can create an API to query user orders. Here is a simple HTTP GET request handler example:

import (
    "github.com/gin-gonic/gin"
    "net/http"
)

func GetOrders(c *gin.Context) {
    user_id := c.Query("user_id")
    db, err := ConnectDB()
    if err != nil {
        c.JSON(http.StatusInternalServerError, err.Error())
        return
    }
    defer db.Close()

    var orders []Order
    db.Where("user_id=?", user_id).Find(&orders)
    c.JSON(http.StatusOK, orders)
}

The above code will query for orders for a specific user ID and return the results as a JSON response.

4. Create test cases

Finally, we need to write some test cases for our order query functionality. The following is a simple test case:

import (
    "encoding/json"
    "github.com/stretchr/testify/assert"
    "net/http"
    "net/http/httptest"
    "testing"
)

func TestGetOrders(t *testing.T) {
    router := gin.Default()
    router.GET("/orders", GetOrders)

    w := httptest.NewRecorder()
    req, _ := http.NewRequest("GET", "/orders?user_id=1", nil)
    router.ServeHTTP(w, req)

    assert.Equal(t, http.StatusOK, w.Code)

    var orders []Order
    json.Unmarshal(w.Body.Bytes(), &orders)
    assert.Equal(t, 1, len(orders))
}

The above code uses the testify and httptest libraries to test whether our API returns as expected.

Summary

In this article, we introduced how to use Go language to develop a simple order query function and provided detailed code examples. You can follow these steps to develop your own order query functionality, changing and customizing it as needed.

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