Скачать или смотреть How to Create a Mongoose Schema that Accepts Only Discrete Values: lang Field Validations Made Easy

Learn how to configure a Mongoose schema to restrict a field to accept only specific values using the `enum` feature, ensuring better data integrity in your MongoDB applications.
---
This video is based on the question https://stackoverflow.com/q/69242362/ asked by the user 'Soumalya Bhattacharya' ( https://stackoverflow.com/u/13604662/ ) and on the answer https://stackoverflow.com/a/69242720/ provided by the user 'Soumalya Bhattacharya' ( https://stackoverflow.com/u/13604662/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to create a mongoose schema to accept only some discreet values

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Create a Mongoose Schema that Accepts Only Discrete Values

When working with MongoDB and Mongoose, it’s essential to ensure that your data remains consistent and valid. One common requirement is to restrict a field to accept only specific values. In this guide, we'll explore how to set up a Mongoose schema that accepts discrete values for a field, ensuring clean and meaningful data entry.

Understanding the Problem

Imagine you have a schema where you want to store language details. For instance, you may want to ensure the language field only accepts values like 'eng' (for English) or 'hbrw' (for Hebrew). If the field receives any other value, it should return an error. Although you could implement this validation using an if-else statement in your application logic, it’s much more effective to embed this validation directly within your Mongoose schema.

Setting Up Your Mongoose Schema

To restrict the language field values in your Mongoose schema, we will utilize the enum validator, which allows us to define an array of accepted values. Here is a step-by-step guide to creating such a schema.

Step 1: Initialize Mongoose

First, ensure that you have Mongoose installed and required in your project:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Define Your Schema with Enum

Now, we will define our schema including the language field with the enum option. This is how you can structure your code:

[[See Video to Reveal this Text or Code Snippet]]

required: This ensures that the language field must be provided.

enum: This array holds the accepted values. If any other value is assigned to language, it will trigger a validation error.

default: This specifies a default value that will be used if none is provided.

Step 3: Compile the Model

Compile your model using the schema you defined:

[[See Video to Reveal this Text or Code Snippet]]

Final Code Snippet

Here’s the complete code for your Mongoose schema:

[[See Video to Reveal this Text or Code Snippet]]

Testing Your Schema

Once you have your schema set up, you can test it by attempting to create instances of your model. Here's how you can test the functionality:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

With just a few lines of code, you can effectively validate that your language field only accepts specific, predefined values. Using Mongoose's enum feature not only simplifies your code but enhances data integrity by avoiding invalid data entries.

Thank you to @ turivishal for providing the solution to create such validations within a Mongoose schema. By following the steps outlined above, you can easily replicate this pattern for other fields within your applications, keeping your databases clean and well-structured.