https://github.com/longbridge/nested-set
Nested Set is an Go implementation of the Nested set model for Gorm.
https://github.com/longbridge/nested-set
gorm nested nested-set tree
Last synced: 11 months ago
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Nested Set is an Go implementation of the Nested set model for Gorm.
- Host: GitHub
- URL: https://github.com/longbridge/nested-set
- Owner: longbridge
- License: mit
- Created: 2020-12-04T10:43:08.000Z (over 5 years ago)
- Default Branch: main
- Last Pushed: 2023-01-10T02:53:07.000Z (about 3 years ago)
- Last Synced: 2025-04-25T00:58:40.531Z (11 months ago)
- Topics: gorm, nested, nested-set, tree
- Language: Go
- Homepage:
- Size: 92.8 KB
- Stars: 69
- Watchers: 2
- Forks: 19
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Nested Set for Go
[](https://github.com/longbridgeapp/nested-set/actions?query=workflow%3Abuild)
Nested Set is an implementation of the [Nested set model](https://en.wikipedia.org/wiki/Nested_set_model) for [Gorm](https://gorm.io/index.html).
This project is the Go version of [awesome_nested_set](https://github.com/collectiveidea/awesome_nested_set), which uses the same data structure design, so it uses the same data together with [awesome_nested_set](https://github.com/collectiveidea/awesome_nested_set).
> Actually the original design is for this, the content managed by [awesome_nested_set](https://github.com/collectiveidea/awesome_nested_set) in our Rails application, the front-end Go API also needs to be maintained.
This is a Go version of the [awesome_nested_set](https://github.com/collectiveidea/awesome_nested_set), and it built for compatible with [awesome_nested_set](https://github.com/collectiveidea/awesome_nested_set).
## What Go Nested Set can do?
For manage a nested tree node like this:
> Video taken from [BlueDoc](https://github.com/huacnlee/bluedoc), used by awesome_nested_set + [react-dnd](https://react-dnd.github.io/react-dnd/examples/sortable/simple).
## Installation
```
go get github.com/longbridgeapp/nested-set
```
## Usage
### Define the model
You must use `nestedset` Stuct tag to define your Gorm model like this:
Support struct tags:
- `id` - int64 - Primary key of the node
- `parent_id` - sql.NullInt64 - ParentID column, null is root
- `lft` - int
- `rgt` - int
- `depth` - int - Depth of the node
- `children_count` - Number of children
Optional:
- `scope` - restricts what is to be considered a list. You can also setup scope by multiple attributes.
Example:
```go
import (
"database/sql"
"github.com/longbridgeapp/nested-set"
)
// Category
type Category struct {
ID int64 `gorm:"PRIMARY_KEY;AUTO_INCREMENT" nestedset:"id"`
ParentID sql.NullInt64 `nestedset:"parent_id"`
UserType string `nestedset:"scope"`
UserID int64 `nestedset:"scope"`
Rgt int `nestedset:"rgt"`
Lft int `nestedset:"lft"`
Depth int `nestedset:"depth"`
ChildrenCount int `nestedset:"children_count"`
Title string
}
```
### Move Node
```go
import nestedset "github.com/longbridgeapp/nested-set"
// create a new node root level last child
nestedset.Create(tx, &node, nil)
// create a new node as parent first child
nestedset.Create(tx, &node, &parent)
// nestedset.MoveDirectionLeft
// nestedset.MoveDirectionRight
// nestedset.MoveDirectionInner
nestedset.MoveTo(tx, node, to, nestedset.MoveDirectionLeft)
```
### Get Nodes with tree order
```go
// With scope, limit tree in a scope
tx := db.Model(&Category{}).Where("user_type = ? AND user_id = ?", "User", 100)
// Get all nodes
categories, _ := tx.Order("lft asc").Error
// Get root nodes
categories, _ := tx.Where("parent_id IS NULL").Order("lft asc").Error
// Get childrens
categories, _ := tx.Where("parent_id = ?", parentCategory.ID).Order("lft asc").Error
```
## Testing
```bash
$ createdb nested-set-test
$ go test ./...
```
```SQL
-- some useful sql to check status
SELECT n.id,
CONCAT(REPEAT('. . ', (COUNT(p.id) - 1)::int), n.title) AS t,
n.title, n.lft, n.rgt, n.depth, n.children_count
FROM categories AS n, categories AS p
WHERE (n.lft BETWEEN p.lft AND p.rgt)
GROUP BY n.id ORDER BY n.lft;
```
## License
MIT