Go 如何添加关系数据

我开始学习戈朗与样本项目从

我的第一个项目已经运行良好。但是我想要一些自定义输出。我的意思是，当我获取订单数据时，我想获取关系数据有很多，但我失败了

从我的简单案例开始，我有两个表（顺序和详细顺序）。一个订单有一个或多个明细单

我的主人叫你去

    package handlers

    import (
        "github.com/berthojoris/ginbro/models"
        "github.com/gin-gonic/gin"
    )

    func init() {
        groupApi.GET("order", orderAll)
        groupApi.GET("order/:id", orderOne)
        groupApi.POST("order", orderCreate)
        groupApi.PATCH("order", orderUpdate)
        groupApi.DELETE("order/:id", orderDelete)
    }

    //All
    func orderAll(c *gin.Context) {
        mdl := models.Order{}
        query := &models.PaginationQuery{}
        err := c.ShouldBindQuery(query)
        if handleError(c, err) {
            return
        }
        list, total, err := mdl.All(query)
        if handleError(c, err) {
            return
        }
        jsonPagination(c, list, total, query)
    }

    //One
    func orderOne(c *gin.Context) {
        var mdl models.Order
        id, err := parseParamID(c)
        if handleError(c, err) {
            return
        }
        mdl.Id = id
        data, err := mdl.One()
        if handleError(c, err) {
            return
        }
        jsonData(c, data)
    }

    //Create
    func orderCreate(c *gin.Context) {
        var mdl models.Order
        err := c.ShouldBind(&mdl)
        if handleError(c, err) {
            return
        }
        err = mdl.Create()
        if handleError(c, err) {
            return
        }
        jsonData(c, mdl)
    }

    //Update
    func orderUpdate(c *gin.Context) {
        var mdl models.Order
        err := c.ShouldBind(&mdl)
        if handleError(c, err) {
            return
        }
        err = mdl.Update()
        if handleError(c, err) {
            return
        }
        jsonSuccess(c)
    }

    //Delete
    func orderDelete(c *gin.Context) {
        var mdl models.Order
        id, err := parseParamID(c)
        if handleError(c, err) {
            return
        }
        mdl.Id = id
        err = mdl.Delete()
        if handleError(c, err) {
            return
        }
        jsonSuccess(c)
    }

我的型号是“订购”的

package models

import (
    "errors"
    "time"
)

var _ = time.Thursday

//Order
type Order struct {
    Id    uint    `gorm:"column:id" form:"id" json:"id" comment:"" sql:"int(10),PRI"`
    Total float64 `gorm:"column:total" form:"total" json:"total" comment:"" sql:"double"`
    OrderDetail []OrderDetail `gorm:"foreignkey:OrderID" json:"detail_order"`
}

//TableName
func (m *Order) TableName() string {
    return "order"
}

//One
func (m *Order) One() (one *Order, err error) {
    one = &Order{}
    err = crudOne(m, one)
    return
}

//All
func (m *Order) All(q *PaginationQuery) (list *[]Order, total uint, err error) {
    list = &[]Order{}
    total, err = crudAll(m, q, list)
    return
}

//Update
func (m *Order) Update() (err error) {
    where := Order{Id: m.Id}
    m.Id = 0

    return crudUpdate(m, where)
}

//Create
func (m *Order) Create() (err error) {
    m.Id = 0

    return mysqlDB.Create(m).Error
}

//Delete
func (m *Order) Delete() (err error) {
    if m.Id == 0 {
        return errors.New("resource must not be zero value")
    }
    return crudDelete(m)
}

我的型号\u订单\u详细信息。开始

package models

import (
    "errors"
    "time"
)

var _ = time.Thursday

//OrderDetail
type OrderDetail struct {
    Id        uint    `gorm:"column:id" form:"id" json:"id" comment:"" sql:"int(10),PRI"`
    OrderId   int     `gorm:"column:order_id" form:"order_id" json:"order_id" comment:"" sql:"int(10),MUL"`
    ItemId    int     `gorm:"column:item_id" form:"item_id" json:"item_id" comment:"" sql:"int(10)"`
    ItemName  string  `gorm:"column:item_name" form:"item_name" json:"item_name" comment:"" sql:"varchar(100)"`
    ItemPrice float64 `gorm:"column:item_price" form:"item_price" json:"item_price" comment:"" sql:"double"`
}

//TableName
func (m *OrderDetail) TableName() string {
    return "order_detail"
}

//One
func (m *OrderDetail) One() (one *OrderDetail, err error) {
    one = &OrderDetail{}
    err = crudOne(m, one)
    return
}

//All
func (m *OrderDetail) All(q *PaginationQuery) (list *[]OrderDetail, total uint, err error) {
    list = &[]OrderDetail{}
    total, err = crudAll(m, q, list)
    return
}

//Update
func (m *OrderDetail) Update() (err error) {
    where := OrderDetail{Id: m.Id}
    m.Id = 0

    return crudUpdate(m, where)
}

//Create
func (m *OrderDetail) Create() (err error) {
    m.Id = 0

    return mysqlDB.Create(m).Error
}

//Delete
func (m *OrderDetail) Delete() (err error) {
    if m.Id == 0 {
        return errors.New("resource must not be zero value")
    }
    return crudDelete(m)
}

还有我的db_助手

package models

import (
    "errors"
    "fmt"
    "github.com/jinzhu/gorm"
    "reflect"
    "strconv"
    "strings"
)

//PaginationQuery gin handler query binding struct
type PaginationQuery struct {
    Where  string `form:"where"`
    Fields string `form:"fields"`
    Order  string `form:"order"`
    Offset uint   `form:"offset"`
    Limit  uint   `form:"limit"`
}

//String to string
func (pq *PaginationQuery) String() string {
    return fmt.Sprintf("w=%v_f=%s_o=%s_of=%d_l=%d", pq.Where, pq.Fields, pq.Order, pq.Offset, pq.Limit)
}

func crudAll(m interface{}, q *PaginationQuery, list interface{}) (total uint, err error) {
    var tx *gorm.DB
    total, tx = getResourceCount(m, q)
    if q.Fields != "" {
        columns := strings.Split(q.Fields, ",")
        if len(columns) > 0 {
            tx = tx.Select(q.Fields)
        }
    }
    if q.Order != "" {
        tx = tx.Order(q.Order)
    }
    if q.Offset > 0 {
        tx = tx.Offset(q.Offset)
    }
    if q.Limit <= 0 {
        q.Limit = 15
    }
    err = tx.Limit(q.Limit).Find(list).Error
    return
}

func crudOne(m interface{}, one interface{}) (err error) {
    if mysqlDB.Where(m).First(one).RecordNotFound() {
        return errors.New("resource is not found")
    }
    return nil
}

func crudUpdate(m interface{}, where interface{}) (err error) {
    db := mysqlDB.Model(where).Updates(m)
    if err = db.Error; err != nil {
        return
    }
    if db.RowsAffected != 1 {
        return errors.New("id is invalid and resource is not found")
    }
    return nil
}

func crudDelete(m interface{}) (err error) {
    //WARNING When delete a record, you need to ensure it’s primary field has value, and GORM will use the primary key to delete the record, if primary field’s blank, GORM will delete all records for the model
    //primary key must be not zero value
    db := mysqlDB.Delete(m)
    if err = db.Error; err != nil {
        return
    }
    if db.RowsAffected != 1 {
        return errors.New("resource is not found to destroy")
    }
    return nil
}
func getResourceCount(m interface{}, q *PaginationQuery) (uint, *gorm.DB) {
    var tx = mysqlDB.Model(m)
    conditions := strings.Split(q.Where, ",")
    for _, val := range conditions {
        w := strings.SplitN(val, ":", 2)
        if len(w) == 2 {
            bindKey, bindValue := w[0], w[1]
            if intV, err := strconv.ParseInt(bindValue, 10, 64); err == nil {
                // bind value is int
                field := fmt.Sprintf("`%s` > ?", bindKey)
                tx = tx.Where(field, intV)
            } else if fV, err := strconv.ParseFloat(bindValue, 64); err == nil {
                // bind value is float
                field := fmt.Sprintf("`%s` > ?", bindKey)
                tx = tx.Where(field, fV)
            } else if bindValue != "" {
                // bind value is string
                field := fmt.Sprintf("`%s` LIKE ?", bindKey)
                sV := fmt.Sprintf("%%%s%%", bindValue)
                tx = tx.Where(field, sV)
            }
        }
    }
    modelName := getType(m)
    rKey := redisPrefix + modelName + q.String() + "_count"
    v, err := mem.GetUint(rKey)
    if err != nil {
        var count uint
        tx.Count(&count)
        mem.Set(rKey, count)
        return count, tx
    }
    return v, tx
}

func getType(v interface{}) string {
    t := reflect.TypeOf(v)
    if t.Kind() == reflect.Ptr {
        return "*" + t.Elem().Name()
    }
    return t.Name()
}

我的关系数据。结果是

即使我有关系数据

我的问题是，如何在

orderstruct

中添加/附加

OrderDetail结构

，以显示表关系数据

---

谢谢

您需要在查询中添加一个

预加载

调用，或者在获取对象后添加一个

相关的

调用。有关用法，请参阅或。如果您使用

Preload

，为了简单起见，我建议您放弃

crudOne

功能，或者根据需要调整它。

是的……感谢@TimBrown的帮助。。。我已经完成了添加的

预加载（“OrderDetail”）

OrderDetail []OrderDetail `gorm:"foreignkey:OrderID" json:"detail_order"`