- Get Started
- Product
- Resources
- Tools & SDKs
- Framework
- Reference
- Get Started
- Product
- Resources
- Tools & SDKs
- Framework
- Reference
5.4.4. Add Columns to a Link
In this chapter, you'll learn how to add custom columns to a link definition and manage them.
How to Add Custom Columns to a Link's Table?#
The defineLink
function used to define a link accepts a third parameter, which is an object of options.
To add custom columns to a link's table, pass in the third parameter of defineLink
a database
property:
1import HelloModule from "../modules/hello"2import ProductModule from "@medusajs/medusa/product"3import { defineLink } from "@medusajs/framework/utils"4 5export default defineLink(6 ProductModule.linkable.product,7 HelloModule.linkable.myCustom,8 {9 database: {10 extraColumns: {11 metadata: {12 type: "json",13 },14 },15 },16 }17)
This adds to the table created for the link between product
and myCustom
a metadata
column of type json
.
Database Options#
The database
property defines configuration for the table created in the database.
Its extraColumns
property defines custom columns to create in the link's table.
extraColumns
's value is an object whose keys are the names of the columns, and values are the column's configurations as an object.
Column Configurations#
The column's configurations object accepts the following properties:
type
: The column's type. Possible values are:string
text
integer
boolean
date
time
datetime
enum
json
array
enumArray
float
double
decimal
bigint
mediumint
smallint
tinyint
blob
uuid
uint8array
defaultValue
: The column's default value.nullable
: Whether the column can havenull
values.
Set Custom Column when Creating Link#
The object you pass to the remote link's create
method accepts a data
property. Its value is an object whose keys are custom column names, and values are the value of the custom column for this link.
For example:
Retrieve Custom Column with Link#
To retrieve linked records with their custom columns, use Query and pass the link definition as the entity
property's value.
For example:
This retrieves the product of id prod_123
and its linked my_custom
records.
In the fields
array you pass metadata
, which is the custom column to retrieve of the link.
Update Custom Column's Value#
The remote link's create
method updates a link's data if the link between the specified records already exists.
So, to update the value of a custom column in a created link, use the create
method again passing it a new value for the custom column.
For example: