nocodb/packages/noco-docs/docs/030.setup-and-usages/060.link-to-another-record.md

---
title: "Link To Another Record"
description: "Understanding Link To Another Record (LTAR) Columns!"
---

### Relationship types:

- One to one
  - A Table record in first table is related to only one record of second table.
  - Example: Country has a capital city
- One to many
  - A Table record in first table is related to more than one record of second table. But second table record maps to only one entry of first table
  - NocoDB refers to this category of relationship as **has many**
  - For every **has many** relation defined, NocoDB augments **belongs to** relationship column in the other table automatically
  - Example: Country **has many** Cities. (other way mapping > City **belongs to** Country )
- Many to many
  - A Table record in first table is related to more than one record of second table; second table record can also map to more than on record of first table.
  - NocoDB refers to this category of relationship as **many to many**
  - For every **many to many** relation defined between tables, NocoDB augments **many to many** relationship column in the other table automatically
  - Example: Film **has many** Actors. Actor **has many** Films (works on many films)

Further details of relationship types can be found [here](https://afteracademy.com/blog/what-are-the-different-types-of-relationships-in-dbms)

Relationships between table records can be established by using **LinkToAnotherRecord** column type.
Workflow details are captured below

## Adding a relationship

<img width="1016" alt="image" src="https://user-images.githubusercontent.com/35857179/189105583-20014dd9-e5a6-4f27-b03c-97fad9096b5f.png" />

### 1. Create column

Click on '+' button at end of column headers

### 2. Update column name

Input name in the text box provided

### 3. Select column type

Select Column type as "LinkToAnotherRecord" from the drop-down menu

### 4. Choose relationship type

- 'Has Many' corresponds to the 'One-to-many' relationships
- 'Many To Many' corresponds to the 'Many-to-many' relationships

### 5. Select child table from drop down menu

### 6. Click on 'Save'

A new column will get created in both the parent table & child table

## Updating linked records

### 1. Open link record tab

Click on the '+' icon in corresponding row - cell
<img width="750" alt="image" src="https://user-images.githubusercontent.com/35857179/189106326-90e46156-798d-4a01-a4eb-4e991ce94c03.png" />

### 2. Select from the option displayed

Use 'Filter box' to narrow down on search items
You can opt to insert a new record as well, using "+ New Record" button
<img width="1014" alt="image" src="https://user-images.githubusercontent.com/35857179/189106494-4b49a200-a44f-41ae-8b54-93b18d867a04.png" />

### 3. Column mapping showing "Has Many" relationship

Sheet1 'has many' Sheet2

<img width="756" alt="image" src="https://user-images.githubusercontent.com/35857179/189106702-3b8d7a50-08f4-4a04-b2cb-16db0cf667b3.png" />

### 4. Column mapping for "Belongs to" relationship [Automatically updated]

Sheet2 'belongs to' Sheet1

<img width="574" alt="image" src="https://user-images.githubusercontent.com/35857179/189106731-59e5bc3c-bcc5-4796-b5b2-d9b5418bfe2b.png" />