📝 Add tutorial and advanced page for EncryptedType

[ravishan16]

Closes #447

This pull request adds documentation for using EncryptedType with SQLModel. It includes:

• A new tutorial with a detailed walkthrough.
• A new page in the "Advanced User Guide" for quick reference.

[github-actions]

📝 Docs preview for commit beb184f at: https://22b95713.sqlmodel.pages.dev

Modified Pages

• https://22b95713.sqlmodel.pages.dev/advanced/encrypted-type/ - (before)
• https://22b95713.sqlmodel.pages.dev/tutorial/encrypted-type/ - (before)

[williambdean]

I am seeing in the sqlalchemy-utils docs that EncryptionType is deprecating in favor StringEncryptedType. Maybe good to swap out. https://sqlalchemy-utils.readthedocs.io/en/latest/data_types.html#encryptedtype

[YuriiMotov]

@ravishan16, thank you for your interest and efforts!

The example is interesting, but I think this should be a section of docs about sa_column property (the code example boils down to just using sa_column to specify SQLAlchemy type for the field).

I also don't think we should add 2 sections about this. I think it should be in Advanced section only.

What do you think?

[github-actions]

📝 Docs preview

Last commit 692ae8f at: https://f5aeaf54.sqlmodel.pages.dev

Modified Pages

• https://f5aeaf54.sqlmodel.pages.dev/advanced/sa-column/ - (before)

[ravishan16]

@ravishan16, thank you for your interest and efforts!

The example is interesting, but I think this should be a section of docs about sa_column property (the code example boils down to just using sa_column to specify SQLAlchemy type for the field).

I also don't think we should add 2 sections about this. I think it should be in Advanced section only.

What do you think?

Thanks @YuriiMotov for the thoughtful feedback, completely agree. I’ve reworked this into a single Advanced page focused on sa_column. The encryption piece is now just one example of passing a fully configured SQLAlchemy Column, rather than a standalone “encrypted type” doc.

Summary of changes:
• Consolidated content into a single Advanced doc: sa-column.md
• Replaced the deprecated EncryptedType with sqlalchemy_utils.StringEncryptedType (with a short note explaining why) as suggested by @williambdean
• Added a second small example to show versatility: enforcing uniqueness via sa_column and a composite UniqueConstraint
• Ensured examples are runnable and consistent
• Removed the old encrypted-type page and updated navigation accordingly

If you’d prefer to keep just one example (e.g., only the encrypted field) or adjust the tone/titles, I’m happy to trim or tweak as needed or you can change it as needed.

[YuriiMotov]

@ravishan16, thank you!

It's already very helpful! But I think we should try to make the style more consistent with other sections. Please, take a look at my comments below.

As for enforcing uniqueness use case - I don't see any advantage of using Column here. I would remove this part to not overload docs with. We can later add more use-cases.

Also, I think we should create a sub-group inside Advanced section like Advanced Column Configuration (let's think about the name, this is just a suggestion) where we will place all things related to customization with sa_column, sa_column_args, sa_type, sa_column_kwargs.

[YuriiMotov]

It would be nice to explain this in a bit more details, make it a bit more entertaining and step-by-step.
Something like (very raw draft):

Remember we have secret_name fields for every Hero?
What if the DB leakage happens and all data becomes public? Everyone will know secret names of our heroes.. 😱
Let's try to mitigate such security risks by introducing data encryption for sensitive data.
All we need is to use StringEncryptedType DB type for secret_name

An then add a part of code example (only related lines with most important lines highlighted) like this

{* ./docs_src/advanced/sa_column/tutorial001.py ln[1:28] hl[4:8,11:12,20:26] *}

Then describe in short what is happening in select_heroes.

[YuriiMotov]

I think we should use standardized text for installation part (see how it's done for fastapi-related section) and move it to the beginning (inside ## Use case: encrypted field with a custom type)

## Use case: encrypted field with a custom type

### Install `sqlalchemy-utils` and `cryptography` packeges

The first step is to install `sqlalchemy-utils` and `cryptography` packeges.

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and then install them, for example with:

<div class="termy">

```console
$ pip install sqlmodel sqlalchemy-utils cryptography

---> 100%
```

</div>