Document System Tutorial Part 5 - Linking Models (Documents)

In this part, we will talk about linking models using a foreign key for documents.

Let’s create a new file in the models folder named channel.go with the following codes below:

package models

import (
    "github.com/uadmin/uadmin"
)

// Channel !
type Channel struct {
    uadmin.Model
    Name string `uadmin:"required"`
}

Create another file in the models folder named document.go with the following codes below. Link the Channel model to the Document model.

package models

import (
    "time"

    "github.com/uadmin/uadmin"
)

// Document !
type Document struct {
    uadmin.Model
    Name        string
    File        string `uadmin:"file"`
    Description string `uadmin:"html"`
    RawText     string `uadmin:"list_exclude"`
    Folder      Folder `uadmin:"filter"`
    FolderID    uint
    CreatedDate time.Time
    Channel     Channel `uadmin:"list_exclude"`
    ChannelID   uint
    CreatedBy   string
}

file tag allows the user to upload a file from your computer.

html tag allows the user to modify text in HTML format.

list_exclude tag hides the field or column name in the model structure.

filter tag adds a field in the uAdmin filter feature to search based on the related field.

CreatedBy field is a reserved word in uAdmin used to display the name of the user who created the record in the model.

And of course, let’s create permissions to the group and user who can access the specific document.

document_group.go

package models

import (
    "github.com/uadmin/uadmin"
)

// DocumentGroup !
type DocumentGroup struct {
    uadmin.Model
    Group      uadmin.UserGroup
    GroupID    uint
    Document   Document
    DocumentID uint
    Read       bool
    Add        bool
    Edit       bool
    Delete     bool
}

// DocumentGroup function that returns string value
func (d *DocumentGroup) String() string {

    // Gives access to the fields in another model
    uadmin.Preload(d)

    // Returns the GroupName from the Group model
    return d.Group.GroupName
}

document_user.go

package models

import (
    "github.com/uadmin/uadmin"
)

// DocumentUser !
type DocumentUser struct {
    uadmin.Model
    User       uadmin.User
    UserID     uint
    Document   Document
    DocumentID uint
    Read       bool
    Add        bool
    Edit       bool
    Delete     bool
}

// DocumentUser function that returns string value
func (d *DocumentUser) String() string {

    // Gives access to the fields in another model
    uadmin.Preload(d)

    // Returns the full name from the User model
    return d.User.String()
}

What if the user updates something in the document then reuploads it? In this situation, let’s create a file named document_version.go. Every updates done by the user, the version number of the document will change.

package models

import (
    "fmt"
    "time"

    "github.com/uadmin/uadmin"
)

// DocumentVersion !
type DocumentVersion struct {
    uadmin.Model
    Document   Document
    DocumentID uint
    File       string `uadmin:"file"`
    Number     int    `uadmin:"help:version number"`
    Date       time.Time
}

// Returns the version number
func (d DocumentVersion) String() string {
    return fmt.Sprint(d.Number)
}

help tag notifies the user to give solutions to advanced tasks.

Now go to main.go and register the models that we have created.

func main() {
    // Register models to uAdmin
    uadmin.Register(
        models.Folder{},
        models.FolderGroup{},
        models.FolderUser{},
        models.Channel{}, // place it here
        models.Document{}, // place it here
        models.DocumentGroup{}, // place it here
        models.DocumentUser{}, // place it here
        models.DocumentVersion{}, // place it here
    )

    // Some codes
}

Run your application. As expected, Channels and Document related models are added in the uAdmin Dashboard.

Click here to view our progress so far.

In the next part, we will discuss about document concepts and how to create records in an application.

• Document System Tutorial Part 5 - Linking Models (Current Progress)