-
-
Notifications
You must be signed in to change notification settings - Fork 2.8k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Merge branch 'develop' into docs/update-config-version-1733335320
- Loading branch information
Showing
4 changed files
with
100 additions
and
2 deletions.
There are no files selected for viewing
86 changes: 86 additions & 0 deletions
86
...apps/book/app/learn/advanced-development/data-models/check-constraints/page.mdx
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,86 @@ | ||
| export const metadata = { | ||
| title: `${pageNumber} Add Data Model Check Constraints`, | ||
| } | ||
|
|
||
| # {metadata.title} | ||
|
|
||
| In this chapter, you'll learn how to add check constraints to your data model. | ||
|
|
||
| ## What is a Check Constraint? | ||
|
|
||
| A check constraint is a condition that must be satisfied by records inserted into a database table, otherwise an error is thrown. | ||
|
|
||
| For example, if you have a data model with a `price` property, you want to only allow positive number values. So, you add a check constraint that fails when inserting a record with a negative price value. | ||
|
|
||
| --- | ||
|
|
||
| ## How to Set a Check Constraint? | ||
|
|
||
| To set check constraints on a data model, use the `checks` method. This method accepts an array of check constraints to apply on the data model. | ||
|
|
||
| For example, to set a check constraint on a `price` property that ensures its value can only be a positive number: | ||
|
|
||
| export const checks1Highlights = [ | ||
| ["7", "checks", "Add check constraints to the data model."], | ||
| ["8", "columns", "An object of column names for each property."], | ||
| ["8", "`${columns.price} >= 0`", "Return a SQL check constraint expression."] | ||
| ] | ||
|
|
||
| ```ts highlights={checks1Highlights} | ||
| import { model } from "@medusajs/framework/utils" | ||
|
|
||
| const CustomProduct = model.define('custom_product', { | ||
| // ... | ||
| price: model.bigNumber(), | ||
| }) | ||
| .checks([ | ||
| (columns) => `${columns.price} >= 0` | ||
| ]) | ||
| ``` | ||
|
|
||
| The item passed in the array parameter of `checks` can be a callback function that accepts as a parameter an object whose keys are the names of the properties in the data model schema, and values the respective column name in the database. | ||
|
|
||
| The function returns a string indicating the [SQL check constraint expression](https://www.postgresql.org/docs/current/ddl-constraints.html#DDL-CONSTRAINTS-CHECK-CONSTRAINTS). In the expression, use the `columns` parameter to access a property's column name. | ||
|
|
||
| You can also pass an object to the `checks` method: | ||
|
|
||
| export const checks2Highlights = [ | ||
| ["7", "checks", "Add check constraints to the data model."], | ||
| ["9", "name", "The check constraint's name."], | ||
| ["10", "expression", "A function that returns the SQL check constraint expression."] | ||
| ] | ||
|
|
||
| ```ts highlights={checks2Highlights} | ||
| import { model } from "@medusajs/framework/utils" | ||
|
|
||
| const CustomProduct = model.define('custom_product', { | ||
| // ... | ||
| price: model.bigNumber(), | ||
| }) | ||
| .checks([ | ||
| { | ||
| name: 'custom_product_price_check', | ||
| expression: (columns) => `${columns.price} >= 0` | ||
| } | ||
| ]) | ||
| ``` | ||
|
|
||
| The object accepts the following properties: | ||
|
|
||
| - `name`: The check constraint's name. | ||
| - `expression`: A function similar to the one that can be passed to the array. It accepts an object of columns and returns an [SQL check constraint expression](https://www.postgresql.org/docs/current/ddl-constraints.html#DDL-CONSTRAINTS-CHECK-CONSTRAINTS). | ||
|
|
||
| --- | ||
|
|
||
| ## Apply in Migrations | ||
|
|
||
| After adding the check constraint, make sure to generate and run migrations if you already have the table in the database. Otherwise, the check constraint won't be reflected. | ||
|
|
||
| To generate a migration for the data model's module then reflect it on the database, run the following command: | ||
|
|
||
| ```bash | ||
| npx medusa db:generate custom_module | ||
| npx medusa db:migrate | ||
| ``` | ||
|
|
||
| The first command generates the migration under the `migrations` directory of your module's directory, and the second reflects it on the database. |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters