Скачать с ютуб Fixing the ValidationError for datetime in FastAPI with PostgreSQL and SQLAlchemy в хорошем качестве

Fixing the ValidationError for datetime in FastAPI with PostgreSQL and SQLAlchemy

A comprehensive guide to resolve `ValidationError` for datetime fields while using FastAPI, SQLAlchemy, and PostgreSQL in your projects. --- This video is based on the question https://stackoverflow.com/q/69484851/ asked by the user 'JoeZHH' ( https://stackoverflow.com/u/8562084/ ) and on the answer https://stackoverflow.com/a/69484950/ provided by the user 'FalkZerd' ( https://stackoverflow.com/u/16721657/ ) 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: ValidationError for datetime 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. --- Understanding and Fixing ValidationError for datetime in FastAPI When working with FastAPI, SQLAlchemy, and PostgreSQL, you may come across various errors that can be frustrating. One such common error is the ValidationError, particularly related to datetime fields when using Pydantic models. In this guide, we'll explore the specifics of this error, its causes, and how to effectively solve it. The Problem Here's the scenario: You are developing a demo project following a guide using FastAPI, SQLAlchemy, and PostgreSQL. You’ve set up your database and models successfully and can create posts in your database without any apparent issues. However, upon trying to return the created post from your API endpoint, you encounter the following error message: [[See Video to Reveal this Text or Code Snippet]] Cause of the Problem The ValidationError suggests that there's a field, date_create, which is required by the Pydantic model (Post) but isn't being populated when returning the response. As you can see from the error message, it indicates that this specific field is missing. Detailed Breakdown of the Solution To fix this issue, let's take a closer look at the components involved: your SQLAlchemy model, Pydantic schema, and the creation function. 1. SQLAlchemy Model Your SQLAlchemy model is defined as: [[See Video to Reveal this Text or Code Snippet]] 2. Pydantic Schema Your Pydantic schema includes: [[See Video to Reveal this Text or Code Snippet]] 3. The Fix The main issue here is that there’s a mismatch in naming. Your SQLAlchemy model refers to the field as date_created, while in the Pydantic model, you have mistakenly named it date_create. This is why Pydantic raises a validation error—because it looks for date_create, but it’s never set during your create_post method. Solution Steps Update the Pydantic Schema: Change the field name from date_create to date_created in the Pydantic model: [[See Video to Reveal this Text or Code Snippet]] Return Correct Data: Ensure you're returning all required fields in your API response including the date_created field. 4. Testing the Fix After making this change, test your endpoint again. You should be able to create a post, and the response should now correctly include all fields defined in your Pydantic model without triggering any validation errors. Conclusion Debugging ValidationError in FastAPI can feel overwhelming, but with a systematic approach, it's manageable. Always ensure that your model definitions in SQLAlchemy and Pydantic are aligned, especially with regards to field names. Following the steps outlined in this post should greatly reduce these types of errors in your applications. If you continue to experience issues, consider revisiting your entire API flow, verifying the schemas and models at each step. Happy coding!