如何在gorm中获取结构（内部结构）值

Question

I'm newbie of Golang and GORM. I get some issues on it. How can I get the inside struct value? (Like a nested struct in golang), I tried but, i didn't get actual result.

I have three structs

Department Struct

type Department struct {
    gorm.Model
    DepartmentName string
    DeptCode       string
    Employee       Employee //Employee struct
}

Employee struct

type Employee struct {
    gorm.Model
    EmpId           string
    EmpName         string
    DepartmentID    uint //Department id
    EmployeeContact []EmployeeContact //Array of Employee contact
}

Employee Contact

type EmployeeContact struct {
    gorm.Model
    ContactType string
    ContacText  string
    EmployeeID  uint //Employee Id
}

Relationship

# Department is a Parent of Employee.

# Employee is a Parent of Employee contacts.

I used GORM (Joins)

var departmentStruct model.Department
var employeeStruct model.Employee

    db.Debug().Model(&departmentStruct).Joins("JOIN employees ON employees.department_id = departments.id").Joins("JOIN employee_contacts ON employee_contacts.employee_id = employees.id").Select("employees.id,departments.department_name,departments.dept_code,employees.emp_id,employees.emp_name,employee_contacts.contact_type").Scan(&employeeStruct)
    res1B, _ := json.Marshal(employeeStruct)
    fmt.Fprintln(w, string(res1B))

It will be return the output is

{

    "ID":1,
    "EmpId":"001",
    "EmpName":"samsung",
    "DepartmentID":0, 
    "EmployeeContact":{ //It will be return empty
        "ID":0,
        "CreatedAt":"0001-01-01T00:00:00Z",
        "UpdatedAt":"0001-01-01T00:00:00Z",
        "DeletedAt":null,
        "ContactType":"",
        "ContacText":"",
        "EmployeeID":0
    }

}

I need, When I pass Employee id it will be return like given below format

{

    "ID":1,
    "EmpId":"001",
    "EmpName":"samsung",
    "Department":{
        "ID":1,
        "CreatedAt":"0001-01-01T00:00:00Z",
        "UpdatedAt":"0001-01-01T00:00:00Z",
        "DeletedAt":null,
        "DepartmentName":"Software Analyst",
        "deptCode":"SA"
    },
    "EmployeeContact":[
        {
            "ID":1,
            "CreatedAt":"0001-01-01T00:00:00Z",
            "UpdatedAt":"0001-01-01T00:00:00Z",
            "DeletedAt":null,
            "ContactType":"Home",
            "ContacText":"1234567890",
            "EmployeeID":1
        },
        {
            "ID":2,
            "CreatedAt":"0001-01-01T00:00:00Z",
            "UpdatedAt":"0001-01-01T00:00:00Z",
            "DeletedAt":null,
            "ContactType":"Office",
            "ContacText":"0123456789",
            "EmployeeID":1
        }
    ]
}

Any one can teach me?. How can I achieve it. Thanks.

Answer 1

First of all you probably want your employee model to like this

type Employee struct {
    gorm.Model
    EmpId           string
    EmpName         string
    Department      Department
    DepartmentID    uint //Department id
    EmployeeContact []EmployeeContact //Array of Employee contact
}

And then this preload should do the trick

var employee []model.Employee

err := db.Preload("Department").Preload("EmployeeContact").Find(&employee).Error

and them employee parameter should have list of all employees in your system with preloaded relations