Pydantic has special support for `Decimal` types using the <a href="https://pydantic-docs.helpmanual.io/usage/types/#arguments-to-condecimal" class="external-link" target="_blank">`condecimal()` special function</a>.
-!!! tip
- Pydantic 1.9, that will be released soon, has improved support for `Decimal` types, without needing to use the `condecimal()` function.
+/// tip
- But meanwhile, you can already use this feature with `condecimal()` in **SQLModel** it as it's explained here.
+Pydantic 1.9, that will be released soon, has improved support for `Decimal` types, without needing to use the `condecimal()` function.
+
+But meanwhile, you can already use this feature with `condecimal()` in **SQLModel** it as it's explained here.
+
+///
When you use `condecimal()` you can specify the number of digits and decimal places to support. They will be validated by Pydantic (for example when using FastAPI) and the same information will also be used for the database columns.
-!!! info
- For the database, **SQLModel** will use <a href="https://docs.sqlalchemy.org/en/14/core/type_basics.html#sqlalchemy.types.DECIMAL" class="external-link" target="_blank">SQLAlchemy's `DECIMAL` type</a>.
+/// info
+
+For the database, **SQLModel** will use <a href="https://docs.sqlalchemy.org/en/14/core/type_basics.html#sqlalchemy.types.DECIMAL" class="external-link" target="_blank">SQLAlchemy's `DECIMAL` type</a>.
+
+///
## Decimals in SQLModel
* `123`
* Even though this number doesn't have any decimals, we still have 3 places saved for them, which means that we can **only use 2 places** for the **integer part**, and this number has 3 integer digits. So, the allowed number of integer digits is `max_digits` - `decimal_places` = 2.
-!!! tip
- Make sure you adjust the number of digits and decimal places for your own needs, in your own application. 🤓
+/// tip
+
+Make sure you adjust the number of digits and decimal places for your own needs, in your own application. 🤓
+
+///
## Create models with Decimals
</div>
-!!! warning
- Although Decimal types are supported and used in the Python side, not all databases support it. In particular, SQLite doesn't support decimals, so it will convert them to the same floating `NUMERIC` type it supports.
+/// warning
+
+Although Decimal types are supported and used in the Python side, not all databases support it. In particular, SQLite doesn't support decimals, so it will convert them to the same floating `NUMERIC` type it supports.
+
+But decimals are supported by most of the other SQL databases. 🎉
- But decimals are supported by most of the other SQL databases. 🎉
+///
# Intro to Databases
-!!! info
- Are you a seasoned developer and already know everything about databases? 🤓
+/// info
- Then you can skip to the [Tutorial - User Guide: First Steps](tutorial/index.md){.internal-link target=_blank} right away.
+Are you a seasoned developer and already know everything about databases? 🤓
+
+Then you can skip to the [Tutorial - User Guide: First Steps](tutorial/index.md){.internal-link target=_blank} right away.
+
+///
If you don't know everything about databases, here's a quick overview.
A **database** is a system to store and manage data in a structured and very efficient way.
-!!! tip
- It's very common to abbreviate the word "database" as **"DB"**.
+/// tip
+
+It's very common to abbreviate the word "database" as **"DB"**.
+
+///
As there's a lot of information about databases, and it can get very technical and academic, I'll give you a quick overview about some of the main concepts here.
When starting to program, it might **not be obvious** why having a database apart from the code for your program is a **good idea**. Let's start with that.
-!!! tip
- If that's obvious to you, just continue in the next section below. 👇
+/// tip
+
+If that's obvious to you, just continue in the next section below. 👇
+
+///
In your code you already have **variables**, **dictionaries**, **lists**, etc. They all store **data** in some way already. Why would you need to have a separate database?
I'll tell you more about SQL, SQLModel, how to use them, and how they are related in the next sections.
-!!! info "Technical Details"
- SQLModel is built on top of SQLAlchemy. It is, in fact, just <a href="https://www.sqlalchemy.org/" class="external-link" target="_blank">SQLAlchemy</a> and <a href="https://pydantic-docs.helpmanual.io/" class="external-link" target="_blank">Pydantic</a> mixed together with some sugar on top.
+/// info | Technical Details
+
+SQLModel is built on top of SQLAlchemy. It is, in fact, just <a href="https://www.sqlalchemy.org/" class="external-link" target="_blank">SQLAlchemy</a> and <a href="https://pydantic-docs.helpmanual.io/" class="external-link" target="_blank">Pydantic</a> mixed together with some sugar on top.
+
+///
## NoSQL Databases
SELECT * FROM hero WHERE id = "2; DROP TABLE hero;";
```
-!!! tip
- Notice the double quotes (`"`) making it a string instead of more raw SQL.
+/// tip
+
+Notice the double quotes (`"`) making it a string instead of more raw SQL.
+
+///
The database will not find any record with that ID:
But we never deleted the `hero` table. 🎉
-!!! info
- Of course, there are also other ways to do SQL data sanitization without using a tool like **SQLModel**, but it's still a nice feature you get by default.
+/// info
+
+Of course, there are also other ways to do SQL data sanitization without using a tool like **SQLModel**, but it's still a nice feature you get by default.
+
+///
### Editor Support
## SQL Table Names
-!!! info "Technical Background"
- This is a bit of boring background for SQL purists. Feel free to skip this section. 😉
+/// info | Technical Background
+
+This is a bit of boring background for SQL purists. Feel free to skip this section. 😉
+
+///
When working with pure SQL, it's common to name the tables in plural. So, the table would be named `heroes` instead of `hero`, because it could contain multiple rows, each with one hero.
So, to keep things consistent, I'll keep using the same table names that **SQLModel** would have generated.
-!!! tip
- You can also override the table name. You can read about it in the Advanced User Guide.
+/// tip
+
+You can also override the table name. You can read about it in the Advanced User Guide.
+
+///
<img class="shadow" src="/img/index/autocompletion01.png">
-!!! info
- Don't worry, adopting this in-development standard only affects/improves editor support.
+/// info
- It doesn't affect performance or correctness. And if the in-progress standard was deprecated your code won't be affected.
+Don't worry, adopting this in-development standard only affects/improves editor support.
- Meanwhile, you will get inline errors (like type checks) and autocompletion on places you wouldn't get with any other library. 🎉
+It doesn't affect performance or correctness. And if the in-progress standard was deprecated your code won't be affected.
+
+Meanwhile, you will get inline errors (like type checks) and autocompletion on places you wouldn't get with any other library. 🎉
+
+///
## Short
* Then **comment** saying that you did that, that's how I will know you really checked it.
-!!! info
- Unfortunately, I can't simply trust PRs that just have several approvals.
+/// info
- Several times it has happened that there are PRs with 3, 5 or more approvals, probably because the description is appealing, but when I check the PRs, they are actually broken, have a bug, or don't solve the problem they claim to solve. 😅
+Unfortunately, I can't simply trust PRs that just have several approvals.
- So, it's really important that you actually read and run the code, and let me know in the comments that you did. 🤓
+Several times it has happened that there are PRs with 3, 5 or more approvals, probably because the description is appealing, but when I check the PRs, they are actually broken, have a bug, or don't solve the problem they claim to solve. 😅
+
+So, it's really important that you actually read and run the code, and let me know in the comments that you did. 🤓
+
+///
* If the PR can be simplified in a way, you can ask for that, but there's no need to be too picky, there might be a lot of subjective points of view (and I will have my own as well 🙈), so it's better if you can focus on the fundamental things.
Join the 👥 <a href="https://discord.gg/VQjSZaeJmf" class="external-link" target="_blank">FastAPI and Friends Discord chat server</a> 👥 and hang out with others in the community. There's a `#sqlmodel` channel.
-!!! tip
- For questions, ask them in <a href="https://github.com/tiangolo/sqlmodel/discussions/new?category=questions" class="external-link" target="_blank">GitHub Discussions</a>, there's a much better chance you will receive help there.
+/// tip
+
+For questions, ask them in <a href="https://github.com/tiangolo/sqlmodel/discussions/new?category=questions" class="external-link" target="_blank">GitHub Discussions</a>, there's a much better chance you will receive help there.
+
+Use the chat only for other general conversations.
- Use the chat only for other general conversations.
+///
### Don't use the chat for questions
Now let's review all this code once again.
-!!! tip
- Each one of the numbered bubbles shows what each line will print in the output.
+/// tip
- And as we created the **engine** with `echo=True`, we can see the SQL statements being executed at each step.
+Each one of the numbered bubbles shows what each line will print in the output.
+
+And as we created the **engine** with `echo=True`, we can see the SQL statements being executed at each step.
+
+///
```{ .python .annotate }
{!./docs_src/tutorial/automatic_id_none_refresh/tutorial002.py!}
You can also do it. 😎 There's a couple of things to keep in mind. 🤓
-!!! warning
- This is a bit more advanced.
+/// warning
- If the solution above already worked for you, that might be enough for you, and you can continue in the next chapter. 🤓
+This is a bit more advanced.
+
+If the solution above already worked for you, that might be enough for you, and you can continue in the next chapter. 🤓
+
+///
Let's assume that now the file structure is:
<img alt="table relationships" src="/img/tutorial/relationships/select/relationships2.svg">
-!!! info
- We will later update **Spider-Boy** to add him to the **Preventers** team too, but not yet.
+/// info
+
+We will later update **Spider-Boy** to add him to the **Preventers** team too, but not yet.
+
+///
We will continue with the code in the previous example and we will add more things to it.
If you had a custom table name, you would use that custom table name.
-!!! info
- You can learn about setting a custom table name for a model in the Advanced User Guide.
+/// info
+
+You can learn about setting a custom table name for a model in the Advanced User Guide.
+
+///
### Create the Tables
## Run the Code
-!!! tip
- Before running the code, make sure you delete the file `database.db` to make sure you start from scratch.
+/// tip
+
+Before running the code, make sure you delete the file `database.db` to make sure you start from scratch.
+
+///
If we run the code we have up to now, it will go and create the database file `database.db` and the tables in it we just defined, `team` and `hero`:
Let's see how to use **SQLModel** to manage connected data in the next chapters. 🤝
-!!! tip
- We will extend this further in the next group of chapters making it even more convenient to work with in Python code, using **relationship attributes**.
+/// tip
- But you should start in this group of chapters first. 🤓
+We will extend this further in the next group of chapters making it even more convenient to work with in Python code, using **relationship attributes**.
+
+But you should start in this group of chapters first. 🤓
+
+///
WHERE hero.team_id = team.id
```
-!!! info
- Because we have two columns called `name`, one for `hero` and one for `team`, we can specify them with the prefix of the table name and the dot to make it explicit what we refer to.
+/// info
+
+Because we have two columns called `name`, one for `hero` and one for `team`, we can specify them with the prefix of the table name and the dot to make it explicit what we refer to.
+
+///
Notice that now in the `WHERE` part we are not comparing one column with a literal value (like `hero.name = "Deadpond"`), but we are comparing two columns.
<img class="shadow" src="/img/tutorial/relationships/select/image01.png">
-!!! note
- Wait, what about Spider-Boy? 😱
+/// note
+
+Wait, what about Spider-Boy? 😱
- He doesn't have a team, so his `team_id` is `NULL` in the database. And this SQL is comparing that `NULL` from the `team_id` with all the `id` fields in the rows in the `team` table.
+He doesn't have a team, so his `team_id` is `NULL` in the database. And this SQL is comparing that `NULL` from the `team_id` with all the `id` fields in the rows in the `team` table.
- As there's no team with an ID of `NULL`, it doesn't find a match.
+As there's no team with an ID of `NULL`, it doesn't find a match.
- But we'll see how to fix that later with a `LEFT JOIN`.
+But we'll see how to fix that later with a `LEFT JOIN`.
+
+///
## Select Related Data with **SQLModel**
And in this `for` loop we assign them to the variable `hero` and the variable `team`.
-!!! info
- There was a lot of research, design, and work behind **SQLModel** to make this provide the best possible developer experience.
+/// info
+
+There was a lot of research, design, and work behind **SQLModel** to make this provide the best possible developer experience.
- And you should get autocompletion and inline errors in your editor for both `hero` and `team`. 🎉
+And you should get autocompletion and inline errors in your editor for both `hero` and `team`. 🎉
+
+///
## Add It to Main
<img class="shadow" src="/img/tutorial/relationships/select/image02.png">
-!!! tip
- Why bother with all this if the result is the same?
+/// tip
+
+Why bother with all this if the result is the same?
+
+This `JOIN` will be useful in a bit to be able to also get Spider-Boy, even if he doesn't have a team.
- This `JOIN` will be useful in a bit to be able to also get Spider-Boy, even if he doesn't have a team.
+///
## Join Tables in **SQLModel**
</tr>
</table>
-!!! tip
- The only difference between this query and the previous is that extra `LEFT OUTER`.
+/// tip
+
+The only difference between this query and the previous is that extra `LEFT OUTER`.
+
+///
And here's another of the SQL variations, you could write `LEFT OUTER JOIN` or just `LEFT JOIN`, it means the same.
A dialog should show up. Go to the [project directory you created](./index.md#create-a-project){.internal-link target=_blank} and save the file with a name of `database.db`.
-!!! tip
- It's common to save SQLite database files with an extension of `.db`. Sometimes also `.sqlite`.
+/// tip
+
+It's common to save SQLite database files with an extension of `.db`. Sometimes also `.sqlite`.
+
+///
## Create a Table
A class like this that represents some data is commonly called a **model**.
-!!! tip
- That's why this package is called `SQLModel`. Because it's mainly used to create **SQL Models**.
+/// tip
+
+That's why this package is called `SQLModel`. Because it's mainly used to create **SQL Models**.
+
+///
For that, we will import `SQLModel` (plus other things we will also use) and create a class `Hero` that inherits from `SQLModel` and represents the **table model** for our heroes:
We use the config `table=True` to tell **SQLModel** that this is a **table model**, it represents a table.
-!!! info
- It's also possible to have models without `table=True`, those would be only **data models**, without a table in the database, they would not be **table models**.
+/// info
+
+It's also possible to have models without `table=True`, those would be only **data models**, without a table in the database, they would not be **table models**.
- Those **data models** will be **very useful later**, but for now, we'll just keep adding the `table=True` configuration.
+Those **data models** will be **very useful later**, but for now, we'll just keep adding the `table=True` configuration.
+
+///
## Define the Fields, Columns
</details>
-!!! tip
- We also define `id` with `Optional`. But we will talk about `id` below.
+/// tip
+
+We also define `id` with `Optional`. But we will talk about `id` below.
+
+///
This way, we tell **SQLModel** that `age` is not required when validating data and that it has a default value of `None`.
So, this column is "nullable" (can be set to `NULL`).
-!!! info
- In terms of **Pydantic**, `age` is an **optional field**.
+/// info
+
+In terms of **Pydantic**, `age` is an **optional field**.
- In terms of **SQLAlchemy**, `age` is a **nullable column**.
+In terms of **SQLAlchemy**, `age` is a **nullable column**.
+
+///
### Primary Key `id`
You should normally have a single **engine** object for your whole application and re-use it everywhere.
-!!! tip
- There's another related thing called a **Session** that normally should *not* be a single object per application.
+/// tip
+
+There's another related thing called a **Session** that normally should *not* be a single object per application.
- But we will talk about it later.
+But we will talk about it later.
+
+///
### Engine Database URL
### Engine Technical Details
-!!! tip
- If you didn't know about SQLAlchemy before and are just learning **SQLModel**, you can probably skip this section, scroll below.
+/// tip
+
+If you didn't know about SQLAlchemy before and are just learning **SQLModel**, you can probably skip this section, scroll below.
+
+///
You can read a lot more about the engine in the <a href="https://docs.sqlalchemy.org/en/14/tutorial/engine.html" class="external-link" target="_blank">SQLAlchemy documentation</a>.
{!./docs_src/tutorial/create_db_and_table/tutorial001.py!}
```
-!!! tip
- Creating the engine doesn't create the `database.db` file.
+/// tip
+
+Creating the engine doesn't create the `database.db` file.
+
+But once we run `SQLModel.metadata.create_all(engine)`, it creates the `database.db` file **and** creates the `hero` table in that database.
- But once we run `SQLModel.metadata.create_all(engine)`, it creates the `database.db` file **and** creates the `hero` table in that database.
+Both things are done in this single step.
- Both things are done in this single step.
+///
Let's unwrap that:
</details>
-!!! tip
- Remember to [activate the virtual environment](./index.md#create-a-python-virtual-environment){.internal-link target=_blank} before running it.
+/// tip
+
+Remember to [activate the virtual environment](./index.md#create-a-python-virtual-environment){.internal-link target=_blank} before running it.
+
+///
Now run the program with Python:
</div>
-!!! info
- I simplified the output above a bit to make it easier to read.
+/// info
- But in reality, instead of showing:
+I simplified the output above a bit to make it easier to read.
- ```
- INFO Engine BEGIN (implicit)
- ```
+But in reality, instead of showing:
- it would show something like:
+```
+INFO Engine BEGIN (implicit)
+```
+
+it would show something like:
+
+```
+2021-07-25 21:37:39,175 INFO sqlalchemy.engine.Engine BEGIN (implicit)
+```
- ```
- 2021-07-25 21:37:39,175 INFO sqlalchemy.engine.Engine BEGIN (implicit)
- ```
+///
### `TEXT` or `VARCHAR`
To make it easier to start using **SQLModel** right away independent of the database you use (even with MySQL), and without any extra configurations, by default, `str` fields are interpreted as `VARCHAR` in most databases and `VARCHAR(255)` in MySQL, this way you know the same class will be compatible with the most popular databases without extra effort.
-!!! tip
- You will learn how to change the maximum length of string columns later in the Advanced Tutorial - User Guide.
+/// tip
+
+You will learn how to change the maximum length of string columns later in the Advanced Tutorial - User Guide.
+
+///
### Verify the Database
Now we would be able to, for example, import the `Hero` class in some other file without having those **side effects**.
-!!! tip
- 😅 **Spoiler alert**: The function is called `create_db_and_tables()` because we will have more **tables** in the future with other classes apart from `Hero`. 🚀
+/// tip
+
+😅 **Spoiler alert**: The function is called `create_db_and_tables()` because we will have more **tables** in the future with other classes apart from `Hero`. 🚀
+
+///
### Create Data as a Script
But we still want it to **create the database and table** when we call it with Python directly as an independent script from the terminal, just as as above.
-!!! tip
- Think of the word **script** and **program** as interchangeable.
+/// tip
- The word **script** often implies that the code could be run independently and easily. Or in some cases it refers to a relatively simple program.
+Think of the word **script** and **program** as interchangeable.
+
+The word **script** often implies that the code could be run independently and easily. Or in some cases it refers to a relatively simple program.
+
+///
For that we can use the special variable `__name__` in an `if` block:
from app import Hero
```
-!!! tip
- That `if` block using `if __name__ == "__main__":` is sometimes called the "**main block**".
+/// tip
+
+That `if` block using `if __name__ == "__main__":` is sometimes called the "**main block**".
+
+The official name (in the <a href="https://docs.python.org/3/library/__main__.html" class="external-link" target="_blank">Python docs</a>) is "**Top-level script environment**".
- The official name (in the <a href="https://docs.python.org/3/library/__main__.html" class="external-link" target="_blank">Python docs</a>) is "**Top-level script environment**".
+///
#### More details
...will **not** be executed.
-!!! info
- For more information, check <a href="https://docs.python.org/3/library/__main__.html" class="external-link" target="_blank">the official Python docs</a>.
+/// info
+
+For more information, check <a href="https://docs.python.org/3/library/__main__.html" class="external-link" target="_blank">the official Python docs</a>.
+
+///
## Last Review
{!./docs_src/tutorial/create_db_and_table/annotations/en/tutorial003.md!}
-!!! tip
- Review what each line does by clicking each number bubble in the code. 👆
+/// tip
+
+Review what each line does by clicking each number bubble in the code. 👆
+
+///
## Recap
{!./docs_src/tutorial/delete/annotations/en/tutorial002.md!}
-!!! tip
- Check out the number bubbles to see what is done by each line of code.
+/// tip
+
+Check out the number bubbles to see what is done by each line of code.
+
+///
## Recap
Let's use the same **offset** and **limit** we learned about in the previous tutorial chapters for the API.
-!!! info
- In many cases, this is also called **pagination**.
+/// info
+
+In many cases, this is also called **pagination**.
+
+///
## Add a Limit and Offset to the Query Parameters
This way, a client can decide to take fewer heroes if they want, but not more.
-!!! info
- If you need to refresh how query parameters and their validation work, check out the docs in FastAPI:
+/// info
+
+If you need to refresh how query parameters and their validation work, check out the docs in FastAPI:
+
+* <a href="https://fastapi.tiangolo.com/tutorial/query-params/" class="external-link" target="_blank">Query Parameters</a>
+* <a href="https://fastapi.tiangolo.com/tutorial/query-params-str-validations/" class="external-link" target="_blank">Query Parameters and String Validations</a>
+* <a href="https://fastapi.tiangolo.com/tutorial/path-params-numeric-validations/" class="external-link" target="_blank">Path Parameters and Numeric Validations</a>
- * <a href="https://fastapi.tiangolo.com/tutorial/query-params/" class="external-link" target="_blank">Query Parameters</a>
- * <a href="https://fastapi.tiangolo.com/tutorial/query-params-str-validations/" class="external-link" target="_blank">Query Parameters and String Validations</a>
- * <a href="https://fastapi.tiangolo.com/tutorial/path-params-numeric-validations/" class="external-link" target="_blank">Path Parameters and Numeric Validations</a>
+///
## Check the Docs UI
This also means that `SQLModel.metadata.create_all()` won't create tables in the database for `HeroCreate` and `HeroRead`, because they don't have `table = True`, which is exactly what we want. 🚀
-!!! tip
- We will improve this code to avoid duplicating the fields, but for now we can continue learning with these models.
+/// tip
+
+We will improve this code to avoid duplicating the fields, but for now we can continue learning with these models.
+
+///
## Use Multiple Models to Create a Hero
This will validate that all the data that we promised is there and will remove any data we didn't declare.
-!!! tip
- This filtering could be very important and could be a very good security feature, for example, to make sure you filter private data, hashed passwords, etc.
+/// tip
+
+This filtering could be very important and could be a very good security feature, for example, to make sure you filter private data, hashed passwords, etc.
+
+You can read more about it in the <a href="https://fastapi.tiangolo.com/tutorial/response-model/" class="external-link" target="_blank">FastAPI docs about Response Model</a>.
- You can read more about it in the <a href="https://fastapi.tiangolo.com/tutorial/response-model/" class="external-link" target="_blank">FastAPI docs about Response Model</a>.
+///
In particular, it will make sure that the `id` is there and that it is indeed an integer (and not `None`).
We want to get the hero based on the `id`, so we will use a **path parameter** `hero_id`.
-!!! info
- If you need to refresh how *path parameters* work, including their data validation, check the <a href="https://fastapi.tiangolo.com/tutorial/path-params/" class="external-link" target="_blank">FastAPI docs about Path Parameters</a>.
+/// info
+
+If you need to refresh how *path parameters* work, including their data validation, check the <a href="https://fastapi.tiangolo.com/tutorial/path-params/" class="external-link" target="_blank">FastAPI docs about Path Parameters</a>.
+
+///
```Python hl_lines="8"
{!./docs_src/tutorial/fastapi/read_one/tutorial001.py[ln:1-4]!}
For example, client generators, that can automatically create the code necessary to talk to your API in many languages.
-!!! info
- If you are curious about the standards, FastAPI generates OpenAPI, that internally uses JSON Schema.
+/// info
- You can read about all that in the <a href="https://fastapi.tiangolo.com/tutorial/first-steps/#openapi" class="external-link" target="_blank">FastAPI docs - First Steps</a>.
+If you are curious about the standards, FastAPI generates OpenAPI, that internally uses JSON Schema.
+
+You can read about all that in the <a href="https://fastapi.tiangolo.com/tutorial/first-steps/#openapi" class="external-link" target="_blank">FastAPI docs - First Steps</a>.
+
+///
## Recap
</details>
-!!! tip
- Here's a tip about that `*,` thing in the parameters.
+/// tip
- Here we are passing the parameter `session` that has a "default value" of `Depends(get_session)` before the parameter `hero`, that doesn't have any default value.
+Here's a tip about that `*,` thing in the parameters.
- Python would normally complain about that, but we can use the initial "parameter" `*,` to mark all the rest of the parameters as "keyword only", which solves the problem.
+Here we are passing the parameter `session` that has a "default value" of `Depends(get_session)` before the parameter `hero`, that doesn't have any default value.
- You can read more about it in the FastAPI documentation <a href="https://fastapi.tiangolo.com/tutorial/path-params-numeric-validations/#order-the-parameters-as-you-need-tricks" class="external-link" target="_blank">Path Parameters and Numeric Validations - Order the parameters as you need, tricks</a>
+Python would normally complain about that, but we can use the initial "parameter" `*,` to mark all the rest of the parameters as "keyword only", which solves the problem.
+
+You can read more about it in the FastAPI documentation <a href="https://fastapi.tiangolo.com/tutorial/path-params-numeric-validations/#order-the-parameters-as-you-need-tricks" class="external-link" target="_blank">Path Parameters and Numeric Validations - Order the parameters as you need, tricks</a>
+
+///
The value of a dependency will **only be used for one request**, FastAPI will call it right before calling your code and will give you the value from that dependency.
And we also need to disable it because in **FastAPI** each request could be handled by multiple interacting threads.
-!!! info
- That's enough information for now, you can read more about it in the <a href="https://fastapi.tiangolo.com/async/" class="external-link" target="_blank">FastAPI docs for `async` and `await`</a>.
+/// info
- The main point is, by ensuring you **don't share** the same **session** with more than one request, the code is already safe.
+That's enough information for now, you can read more about it in the <a href="https://fastapi.tiangolo.com/async/" class="external-link" target="_blank">FastAPI docs for `async` and `await`</a>.
+
+The main point is, by ensuring you **don't share** the same **session** with more than one request, the code is already safe.
+
+///
## **FastAPI** App
## Create Heroes *Path Operation*
-!!! info
- If you need a refresher on what a **Path Operation** is (an endpoint with a specific HTTP Operation) and how to work with it in FastAPI, check out the <a href="https://fastapi.tiangolo.com/tutorial/first-steps/" class="external-link" target="_blank">FastAPI First Steps docs</a>.
+/// info
+
+If you need a refresher on what a **Path Operation** is (an endpoint with a specific HTTP Operation) and how to work with it in FastAPI, check out the <a href="https://fastapi.tiangolo.com/tutorial/first-steps/" class="external-link" target="_blank">FastAPI First Steps docs</a>.
+
+///
Let's create the **path operation** code to create a new hero.
</details>
-!!! info
- If you need a refresher on some of those concepts, checkout the FastAPI documentation:
+/// info
+
+If you need a refresher on some of those concepts, checkout the FastAPI documentation:
- * <a href="https://fastapi.tiangolo.com/tutorial/first-steps/" class="external-link" target="_blank">First Steps</a>
- * <a href="https://fastapi.tiangolo.com/tutorial/path-params/" class="external-link" target="_blank">Path Parameters - Data Validation and Data Conversion</a>
- * <a href="https://fastapi.tiangolo.com/tutorial/body/" class="external-link" target="_blank">Request Body</a>
+* <a href="https://fastapi.tiangolo.com/tutorial/first-steps/" class="external-link" target="_blank">First Steps</a>
+* <a href="https://fastapi.tiangolo.com/tutorial/path-params/" class="external-link" target="_blank">Path Parameters - Data Validation and Data Conversion</a>
+* <a href="https://fastapi.tiangolo.com/tutorial/body/" class="external-link" target="_blank">Request Body</a>
+
+///
## The **SQLModel** Advantage
So we can use intuitive standard Python **type annotations**, and we don't have to duplicate a lot of the code for the database models and the API data models. 🎉
-!!! tip
- We will improve this further later, but for now, it already shows the power of having **SQLModel** classes be both **SQLAlchemy** models and **Pydantic** models at the same time.
+/// tip
+
+We will improve this further later, but for now, it already shows the power of having **SQLModel** classes be both **SQLAlchemy** models and **Pydantic** models at the same time.
+
+///
## Read Heroes *Path Operation*
</div>
-!!! info
- The command `uvicorn main:app` refers to:
+/// info
+
+The command `uvicorn main:app` refers to:
+
+* `main`: the file `main.py` (the Python "module").
+* `app`: the object created inside of `main.py` with the line `app = FastAPI()`.
- * `main`: the file `main.py` (the Python "module").
- * `app`: the object created inside of `main.py` with the line `app = FastAPI()`.
+///
### Uvicorn `--reload`
{!./docs_src/tutorial/fastapi/app_testing/tutorial001/annotations/en/test_main_001.md!}
-!!! tip
- Check out the number bubbles to see what is done by each line of code.
+/// tip
+
+Check out the number bubbles to see what is done by each line of code.
+
+///
That's the **core** of the code we need for all the tests later.
{!./docs_src/tutorial/fastapi/app_testing/tutorial001/annotations/en/test_main_002.md!}
-!!! tip
- Check out the number bubbles to see what is done by each line of code.
+/// tip
+
+Check out the number bubbles to see what is done by each line of code.
+
+///
## Create the Engine and Session for Testing
{!./docs_src/tutorial/fastapi/app_testing/tutorial001/annotations/en/test_main_004.md!}
-!!! tip
- Check out the number bubbles to see what is done by each line of code.
+/// tip
+
+Check out the number bubbles to see what is done by each line of code.
+
+///
That's it, now the test will run using the **in-memory database**, which will be faster and probably safer.
We are using **pytest** to run the tests. And pytest also has a very similar concept to the **dependencies in FastAPI**.
-!!! info
- In fact, pytest was one of the things that inspired the design of the dependencies in FastAPI.
+/// info
+
+In fact, pytest was one of the things that inspired the design of the dependencies in FastAPI.
+
+///
It's a way for us to declare some **code that should be run before** each test and **provide a value** for the test function (that's pretty much the same as FastAPI dependencies).
{!./docs_src/tutorial/fastapi/app_testing/tutorial001/annotations/en/test_main_005.md!}
-!!! tip
- Check out the number bubbles to see what is done by each line of code.
+/// tip
+
+Check out the number bubbles to see what is done by each line of code.
+
+///
**pytest** fixtures work in a very similar way to FastAPI dependencies, but have some minor differences:
{!./docs_src/tutorial/fastapi/app_testing/tutorial001/annotations/en/test_main_006.md!}
-!!! tip
- Check out the number bubbles to see what is done by each line of code.
+/// tip
+
+Check out the number bubbles to see what is done by each line of code.
+
+///
Now we have a **client fixture** that, in turn, uses the **session fixture**.
</details>
-!!! tip
- It's always **good idea** to not only test the normal case, but also that **invalid data**, **errors**, and **corner cases** are handled correctly.
+/// tip
+
+It's always **good idea** to not only test the normal case, but also that **invalid data**, **errors**, and **corner cases** are handled correctly.
+
+That's why we add these two extra tests here.
- That's why we add these two extra tests here.
+///
Now, any additional test functions can be as **simple** as the first one, they just have to **declare the `client` parameter** to get the `TestClient` **fixture** with all the database stuff setup. Nice! 😎
And because the `HeroBase` has some of them as *required* and not optional, we will need to **create a new model**.
-!!! tip
- Here is one of those cases where it probably makes sense to use an **independent model** instead of trying to come up with a complex tree of models inheriting from each other.
+/// tip
- Because each field is **actually different** (we just change it to `Optional`, but that's already making it different), it makes sense to have them in their own model.
+Here is one of those cases where it probably makes sense to use an **independent model** instead of trying to come up with a complex tree of models inheriting from each other.
+
+Because each field is **actually different** (we just change it to `Optional`, but that's already making it different), it makes sense to have them in their own model.
+
+///
So, let's create this new `HeroUpdate` model:
</div>
-!!! tip
- Make sure you don't name it also `sqlmodel`, so that you don't end up overriding the name of the package.
+/// tip
+
+Make sure you don't name it also `sqlmodel`, so that you don't end up overriding the name of the package.
+
+///
### Make sure you have Python
And when you "activate" it, any package that you install, for example with `pip`, will be installed in that virtual environment.
-!!! tip
- There are other tools to manage virtual environments, like <a href="https://python-poetry.org/" class="external-link" target="_blank">Poetry</a>.
+/// tip
+
+There are other tools to manage virtual environments, like <a href="https://python-poetry.org/" class="external-link" target="_blank">Poetry</a>.
- And there are alternatives that are particularly useful for deployment like <a href="https://docs.docker.com/get-started/" class="external-link" target="_blank">Docker</a> and other types of containers. In this case, the "virtual environment" is not just the Python standard files and the installed packages, but the whole system.
+And there are alternatives that are particularly useful for deployment like <a href="https://docs.docker.com/get-started/" class="external-link" target="_blank">Docker</a> and other types of containers. In this case, the "virtual environment" is not just the Python standard files and the installed packages, but the whole system.
+
+///
Go ahead and create a Python virtual environment for this project. And make sure to also upgrade `pip`.
Here are the commands you could use:
-=== "Linux, macOS, Linux in Windows"
-
- <div class="termy">
-
- ```console
- // Remember that you might need to use python3.9 or similar 💡
- // Create the virtual environment using the module "venv"
- $ python3 -m venv env
- // ...here it creates the virtual environment in the directory "env"
- // Activate the virtual environment
- $ source ./env/bin/activate
- // Verify that the virtual environment is active
- # (env) $$ which python
- // The important part is that it is inside the project directory, at "code/sqlmodel-tutorial/env/bin/python"
- /home/leela/code/sqlmodel-tutorial/env/bin/python
- // Use the module "pip" to install and upgrade the package "pip" 🤯
- # (env) $$ python -m pip install --upgrade pip
- ---> 100%
- Successfully installed pip
- ```
-
- </div>
-
-=== "Windows PowerShell"
-
- <div class="termy">
-
- ```console
- // Create the virtual environment using the module "venv"
- # >$ python3 -m venv env
- // ...here it creates the virtual environment in the directory "env"
- // Activate the virtual environment
- # >$ .\env\Scripts\Activate.ps1
- // Verify that the virtual environment is active
- # (env) >$ Get-Command python
- // The important part is that it is inside the project directory, at "code\sqlmodel-tutorial\env\python.exe"
- CommandType Name Version Source
- ----------- ---- ------- ------
- Application python 0.0.0.0 C:\Users\leela\code\sqlmodel-tutorial\env\python.exe
- // Use the module "pip" to install and upgrade the package "pip" 🤯
- # (env) >$ python3 -m pip install --upgrade pip
- ---> 100%
- Successfully installed pip
- ```
-
- </div>
+/// tab | Linux, macOS, Linux in Windows
+
+<div class="termy">
+
+```console
+// Remember that you might need to use python3.9 or similar 💡
+// Create the virtual environment using the module "venv"
+$ python3 -m venv env
+// ...here it creates the virtual environment in the directory "env"
+// Activate the virtual environment
+$ source ./env/bin/activate
+// Verify that the virtual environment is active
+# (env) $$ which python
+// The important part is that it is inside the project directory, at "code/sqlmodel-tutorial/env/bin/python"
+/home/leela/code/sqlmodel-tutorial/env/bin/python
+// Use the module "pip" to install and upgrade the package "pip" 🤯
+# (env) $$ python -m pip install --upgrade pip
+---> 100%
+Successfully installed pip
+```
+
+</div>
+
+///
+
+/// tab | Windows PowerShell
+
+<div class="termy">
+
+```console
+// Create the virtual environment using the module "venv"
+# >$ python3 -m venv env
+// ...here it creates the virtual environment in the directory "env"
+// Activate the virtual environment
+# >$ .\env\Scripts\Activate.ps1
+// Verify that the virtual environment is active
+# (env) >$ Get-Command python
+// The important part is that it is inside the project directory, at "code\sqlmodel-tutorial\env\python.exe"
+CommandType Name Version Source
+----------- ---- ------- ------
+Application python 0.0.0.0 C:\Users\leela\code\sqlmodel-tutorial\env\python.exe
+// Use the module "pip" to install and upgrade the package "pip" 🤯
+# (env) >$ python3 -m pip install --upgrade pip
+---> 100%
+Successfully installed pip
+```
+
+</div>
+
+///
## Install **SQLModel**
You had to open the dictionary a few times, maybe **5 or 10**. That's actually **very little work** compared to what it could have been.
-!!! note "Technical Details"
- Do you like **fancy words**? Cool! Programmers tend to like fancy words. 😅
+/// note | Technical Details
- That <abbr title="a recipe, a sequence of predefined steps that achieve a result">algorithm</abbr> I showed you above is called **Binary Search**.
+Do you like **fancy words**? Cool! Programmers tend to like fancy words. 😅
- It's called like that because you **search** something by splitting the dictionary (or any ordered list of things) in **two** ("binary" means "two") parts. And you do that process multiple times until you find what you want.
+That <abbr title="a recipe, a sequence of predefined steps that achieve a result">algorithm</abbr> I showed you above is called **Binary Search**.
+
+It's called like that because you **search** something by splitting the dictionary (or any ordered list of things) in **two** ("binary" means "two") parts. And you do that process multiple times until you find what you want.
+
+///
### An Index and a Novel
Notice that we didn't set an argument of `default=None` or anything similar. This means that **SQLModel** (thanks to Pydantic) will keep it as a **required** field.
-!!! info
- SQLModel (actually SQLAlchemy) will **automatically generate the index name** for you.
+/// info
+
+SQLModel (actually SQLAlchemy) will **automatically generate the index name** for you.
+
+In this case the generated name would be `ix_hero_name`.
- In this case the generated name would be `ix_hero_name`.
+///
## Query Data
Make sure to open the same database we already created by clicking <kbd>Open Database</kbd> and selecting the same `database.db` file.
-!!! tip
- If you don't have that `database.db` file with the table `hero`, you can re-create it by running the Python program at the top. 👆
+/// tip
+
+If you don't have that `database.db` file with the table `hero`, you can re-create it by running the Python program at the top. 👆
+
+///
Then go to the <kbd>Execute SQL</kbd> tab and copy the SQL from above.
</details>
-!!! tip
- The code above in this file (the omitted code) is just the same code that you see at the top of this chapter.
+/// tip
+
+The code above in this file (the omitted code) is just the same code that you see at the top of this chapter.
- The same code we used before to create the `Hero` model.
+The same code we used before to create the `Hero` model.
+
+///
We are putting that in a function `create_heroes()`, to call it later once we finish it.
The new `Session` takes an `engine` as a parameter. And it will use the **engine** underneath.
-!!! tip
- We will see a better way to create a **session** using a `with` block later.
+/// tip
+
+We will see a better way to create a **session** using a `with` block later.
+
+///
## Add Model Instances to the Session
This makes the interactions with the database more efficient (plus some extra benefits).
-!!! info "Technical Details"
- The session will create a new transaction and execute all the SQL code in that transaction.
+/// info | Technical Details
+
+The session will create a new transaction and execute all the SQL code in that transaction.
+
+This ensures that the data is saved in a single batch, and that it will all succeed or all fail, but it won't leave the database in a broken state.
- This ensures that the data is saved in a single batch, and that it will all succeed or all fail, but it won't leave the database in a broken state.
+///
## Commit the Session Changes
{!./docs_src/tutorial/insert/annotations/en/tutorial003.md!}
-!!! tip
- Review what each line does by clicking each number bubble in the code. 👆
+/// tip
+
+Review what each line does by clicking each number bubble in the code. 👆
+
+///
You can now put it in a `app.py` file and run it with Python. And you will see an output like the one shown above.
Great! We got only 3 heroes as we wanted.
-!!! tip
- We will check out that SQL code more in a bit.
+/// tip
+
+We will check out that SQL code more in a bit.
+
+///
## Select with Offset and Limit
But imagine we are in a user interface showing the results in batches of 3 heroes at a time.
-!!! tip
- This is commonly called "pagination". Because the user interface would normally show a "page" of a predefined number of heroes at a time.
+/// tip
+
+This is commonly called "pagination". Because the user interface would normally show a "page" of a predefined number of heroes at a time.
+
+And then you can interact with the user interface to get the next page, and so on.
- And then you can interact with the user interface to get the next page, and so on.
+///
How do we get the next 3?
</tr>
</table>
-!!! tip
- Notice that it doesn't have any foreign key to other tables.
+/// tip
+
+Notice that it doesn't have any foreign key to other tables.
+
+///
And the `hero` table looks like this:
</tr>
</table>
-!!! info
- Other names used for this **link table** are:
+/// info
+
+Other names used for this **link table** are:
+
+* association table
+* secondary table
+* junction table
+* intermediate table
+* join table
+* through table
+* relationship table
+* connection table
- * association table
- * secondary table
- * junction table
- * intermediate table
- * join table
- * through table
- * relationship table
- * connection table
+I'm using the term "link table" because it's short, doesn't collide with other terms already used (e.g. "relationship"), it's easy to remember how to write it, etc.
- I'm using the term "link table" because it's short, doesn't collide with other terms already used (e.g. "relationship"), it's easy to remember how to write it, etc.
+///
## Link Primary Key
And also, the same row in the table `heroteamlink` points to **one** team, but a single team can be connected to **many** hero-team links, so it's also **one-to-many**.
-!!! tip
- The previous many-to-many relationship was also just two one-to-many relationships combined, but now it's going to be much more explicit.
+/// tip
+
+The previous many-to-many relationship was also just two one-to-many relationships combined, but now it's going to be much more explicit.
+
+///
## Update Link Model
* `team`: has `back_populates="hero_links"`, because in the `Team` model, the attribute will contain the links to the **team's heroes**.
* `hero`: has `back_populates="team_links"`, because in the `Hero` model, the attribute will contain the links to the **hero's teams**.
-!!! info
- In SQLAlchemy this is called an Association Object or Association Model.
+/// info
+
+In SQLAlchemy this is called an Association Object or Association Model.
+
+I'm calling it **Link Model** just because that's easier to write avoiding typos. But you are also free to call it however you want. 😉
- I'm calling it **Link Model** just because that's easier to write avoiding typos. But you are also free to call it however you want. 😉
+///
## Update Team Model
</details>
-!!! tip
- Because we are accessing an attribute in the models right after we commit, with `hero_spider_boy.teams` and `team_z_force.heroes`, the data is refreshed automatically.
+/// tip
- So we don't have to call `session.refresh()`.
+Because we are accessing an attribute in the models right after we commit, with `hero_spider_boy.teams` and `team_z_force.heroes`, the data is refreshed automatically.
+
+So we don't have to call `session.refresh()`.
+
+///
We then commit the change, refresh, and print the updated **Spider-Boy**'s heroes to confirm.
That way, we don't have to deal with an iterable or a list.
-!!! tip
- Notice that `.first()` is a method of the `results` object, not of the `select()` statement.
+/// tip
+
+Notice that `.first()` is a method of the `results` object, not of the `select()` statement.
+
+///
Although this query would find two rows, by using `.first()` we get only the first row.
</details>
-!!! tip
- When writing your own code, this is probably the style you will use most often, as it's shorter, more convenient, and you still get all the power of autocompletion and inline errors.
+/// tip
+
+When writing your own code, this is probably the style you will use most often, as it's shorter, more convenient, and you still get all the power of autocompletion and inline errors.
+
+///
## Print the Data
But in our code, in this exact point in time, we already said that **Spider-Boy** is no longer part of the **Preventers**. 🔥
-!!! tip
- We could revert that later by not committing the **session**, but that's not what we are interested in here.
+/// tip
+
+We could revert that later by not committing the **session**, but that's not what we are interested in here.
+
+///
Here, at this point in the code, in memory, the code expects **Preventers** to *not include* **Spider-Boy**.
</details>
-!!! tip
- This is the same section where we updated `hero_spider_boy.team` to `None` but we *haven't committed* that change yet.
+/// tip
- The same section that caused a problem before.
+This is the same section where we updated `hero_spider_boy.team` to `None` but we *haven't committed* that change yet.
+
+The same section that caused a problem before.
+
+///
## Review the Result
</details>
-!!! tip
- Each **relationship attribute** points to the other one, in the other model, using `back_populates`.
+/// tip
+
+Each **relationship attribute** points to the other one, in the other model, using `back_populates`.
+
+///
Although it's simple code, it can be confusing to think about 😵, because the same line has concepts related to both models in multiple places:
**SQLModel** (actually SQLAlchemy) is smart enough to know that the relationship is established by the `team_id`, as that's the foreign key that points from the `hero` table to the `team` table, so we don't have to specify that explicitly here.
-!!! tip
- There's a couple of things we'll check again in some of the next chapters, about the `List["Hero"]` and the `back_populates`.
+/// tip
- But for now, let's first see how to use these relationship attributes.
+There's a couple of things we'll check again in some of the next chapters, about the `List["Hero"]` and the `back_populates`.
+
+But for now, let's first see how to use these relationship attributes.
+
+///
## Next Steps
Now we will see how to use **Relationship Attributes**, an extra feature of **SQLModel** (and SQLAlchemy) to work with the data in the database in way much more familiar way, and closer to normal Python code.
-!!! info
- When I say "**relationship**" I mean the standard dictionary term, of data related to other data.
+/// info
- I'm not using the term "**relation**" that is the technical, academical, SQL term for a single table.
+When I say "**relationship**" I mean the standard dictionary term, of data related to other data.
+
+I'm not using the term "**relation**" that is the technical, academical, SQL term for a single table.
+
+///
And using those **relationship attributes** is where a tool like **SQLModel** really shines. ✨
</details>
-!!! tip
- The automatic data fetching will work as long as the starting object (in this case the `Hero`) is associated with an **open** session.
+/// tip
- For example, here, **inside** a `with` block with a `Session` object.
+The automatic data fetching will work as long as the starting object (in this case the `Hero`) is associated with an **open** session.
+
+For example, here, **inside** a `with` block with a `Session` object.
+
+///
## Get a List of Relationship Objects
That is actually part of Python, it's the current official solution to handle it.
-!!! info
- There's a lot of work going on in Python itself to make that simpler and more intuitive, and find ways to make it possible to not wrap the class in a string.
+/// info
+
+There's a lot of work going on in Python itself to make that simpler and more intuitive, and find ways to make it possible to not wrap the class in a string.
+
+///
<img class="shadow" src="/img/tutorial/select/image01.png">
-!!! warning
- Here we are getting all the rows.
+/// warning
- If you have thousands of rows, that could be expensive to compute for the database.
+Here we are getting all the rows.
- You would normally want to filter the rows to receive only the ones you want. But we'll learn about that later in the next chapter.
+If you have thousands of rows, that could be expensive to compute for the database.
+
+You would normally want to filter the rows to receive only the ones you want. But we'll learn about that later in the next chapter.
+
+///
### A SQL Shortcut
And notice that in the `select()` function we don't explicitly specify the `FROM` part. It is already obvious to **SQLModel** (actually to SQLAlchemy) that we want to select `FROM` the table `hero`, because that's the one associated with the `Hero` class model.
-!!! tip
- The value of the `statement` returned by `select()` is a special object that allows us to do other things.
+/// tip
+
+The value of the `statement` returned by `select()` is a special object that allows us to do other things.
+
+I'll tell you about that in the next chapters.
- I'll tell you about that in the next chapters.
+///
## Execute the Statement
{!./docs_src/tutorial/select/annotations/en/tutorial002.md!}
-!!! tip
- Check out the number bubbles to see what is done by each line of code.
+/// tip
+
+Check out the number bubbles to see what is done by each line of code.
+
+///
Here it starts to become more evident why we should have a single **engine** for the whole application, but different **sessions** for each group of operations.
So, both sections could be in **different places** and would need their own sessions.
-!!! info
- To be fair, in this example all that code could actually share the same **session**, there's actually no need to have two here.
+/// info
+
+To be fair, in this example all that code could actually share the same **session**, there's actually no need to have two here.
- But it allows me to show you how they could be separated and to reinforce the idea that you should have **one engine** per application, and **multiple sessions**, one per each group of operations.
+But it allows me to show you how they could be separated and to reinforce the idea that you should have **one engine** per application, and **multiple sessions**, one per each group of operations.
+
+///
## Get a List of `Hero` Objects
]
```
-!!! info
- It would actually look more compact, I'm formatting it a bit for you to see that it is actually a list with all the data.
+/// info
+
+It would actually look more compact, I'm formatting it a bit for you to see that it is actually a list with all the data.
+
+///
## Compact Version
But SQLModel's version does a lot of **tricks** with type annotations to make sure you get the best **editor support** possible, no matter if you use **VS Code**, **PyCharm**, or something else. ✨
-!!! info
- There was a lot of work and research, with different versions of the internal code, to improve this as much as possible. 🤓
+/// info
+
+There was a lot of work and research, with different versions of the internal code, to improve this as much as possible. 🤓
+
+///
### SQLModel's `session.exec`
But SQLModel's `Session` still has access to `session.execute()` too.
-!!! tip
- Your editor will give you autocompletion for both `session.exec()` and `session.execute()`.
+/// tip
+
+Your editor will give you autocompletion for both `session.exec()` and `session.execute()`.
+
+📢 Remember to **always use `session.exec()`** to get the best editor support and developer experience.
- 📢 Remember to **always use `session.exec()`** to get the best editor support and developer experience.
+///
### Caveats of **SQLModel** Flavor
In this case, as we only have one hero with the name `"Spider-Boy"`, it will only apply the update in that row.
-!!! info
- Notice that in the `UPDATE` the single equals sign (`=`) means **assignment**, setting a column to some value.
+/// info
- And in the `WHERE` the same single equals sign (`=`) is used for **comparison** between two values, to find rows that match.
+Notice that in the `UPDATE` the single equals sign (`=`) means **assignment**, setting a column to some value.
- This is in contrast to Python and most programming languages, where a single equals sign (`=`) is used for assignment, and two equal signs (`==`) are used for comparisons.
+And in the `WHERE` the same single equals sign (`=`) is used for **comparison** between two values, to find rows that match.
+
+This is in contrast to Python and most programming languages, where a single equals sign (`=`) is used for assignment, and two equal signs (`==`) are used for comparisons.
+
+///
You can try that in **DB Browser for SQLite**:
</tr>
</table>
-!!! tip
- It will probably be more common to find the row to update by `id`, for example:
+/// tip
+
+It will probably be more common to find the row to update by `id`, for example:
+
+```SQL
+UPDATE hero
+SET age=16
+WHERE id = 2
+```
- ```SQL
- UPDATE hero
- SET age=16
- WHERE id = 2
- ```
+But in the example above I used `name` to make it more intuitive.
- But in the example above I used `name` to make it more intuitive.
+///
Now let's do the same update in code, with **SQLModel**.
</div>
-!!! tip
- Notice that by this point, the hero still doesn't have an age.
+/// tip
+
+Notice that by this point, the hero still doesn't have an age.
+
+///
## Set a Field Value
{!./docs_src/tutorial/update/annotations/en/tutorial002.md!}
-!!! tip
- Check out the number bubbles to see what is done by each line of code.
+/// tip
+
+Check out the number bubbles to see what is done by each line of code.
+
+///
## Multiple Updates
</details>
-!!! tip
- Review what each line does by clicking each number bubble in the code. 👆
+/// tip
+
+Review what each line does by clicking each number bubble in the code. 👆
+
+///
## Recap
</tr>
</table>
-!!! tip
- Even if the result is only one row, the database always returns a **table**.
+/// tip
- In this case, a table with only one row.
+Even if the result is only one row, the database always returns a **table**.
+
+In this case, a table with only one row.
+
+///
You can try that out in **DB Browser for SQLite**:
In the example above we are using two equal signs (`==`). That's called the "**equality operator**".
-!!! tip
- An **operator** is just a symbol that is put beside one value or in the middle of two values to do something with them.
+/// tip
+
+An **operator** is just a symbol that is put beside one value or in the middle of two values to do something with them.
- `==` is called the **equality** operator because it checks if two things are **equal**.
+`==` is called the **equality** operator because it checks if two things are **equal**.
+
+///
When writing Python, if you write something using this equality operator (`==`) like:
False
```
-!!! tip
- `<`, `>`, `==`, `>=`, `<=`, and `!=` are all **operators** used for **comparisons**.
+/// tip
+
+`<`, `>`, `==`, `>=`, `<=`, and `!=` are all **operators** used for **comparisons**.
+
+///
But SQLAlchemy adds some magic to the columns/fields in a **model class** to make those Python comparisons have super powers.
I think that alone, having better editor support, autocompletion, and inline errors, is enough to make it worth having expressions instead of keyword arguments. ✨
-!!! tip
- **Expressions** also provide more features for other types of comparisons, shown down below. 👇
+/// tip
+
+**Expressions** also provide more features for other types of comparisons, shown down below. 👇
+
+///
## Exec the Statement
</div>
-!!! tip
- The `results` object is an iterable to be used in a `for` loop.
+/// tip
+
+The `results` object is an iterable to be used in a `for` loop.
+
+Even if we got only one row, we iterate over that `results` object. Just as if it was a list of one element.
- Even if we got only one row, we iterate over that `results` object. Just as if it was a list of one element.
+We'll see other ways to get the data later.
- We'll see other ways to get the data later.
+///
## Other Comparisons
age=93 id=7 name='Captain North America' secret_name='Esteban Rogelios'
```
-!!! tip
- Notice that it didn't select `Black Lion`, because the age is not *strictly* greater than `35`.
+/// tip
+
+Notice that it didn't select `Black Lion`, because the age is not *strictly* greater than `35`.
+
+///
### More Than or Equal
age=93 id=7 name='Captain North America' secret_name='Esteban Rogelios'
```
-!!! tip
- This time we got `Black Lion` too because although the age is not *strictly* greater than `35`it is *equal* to `35`.
+/// tip
+
+This time we got `Black Lion` too because although the age is not *strictly* greater than `35`it is *equal* to `35`.
+
+///
### Less Than
age=32 id=4 name='Tarantula' secret_name='Natalia Roman-on'
```
-!!! tip
- We could imagine that **Spider-Boy** is even **younger**. But because we don't know the age, it is `NULL` in the database (`None` in Python), it doesn't match any of these age comparisons with numbers.
+/// tip
+
+We could imagine that **Spider-Boy** is even **younger**. But because we don't know the age, it is `NULL` in the database (`None` in Python), it doesn't match any of these age comparisons with numbers.
+
+///
### Less Than or Equal
age=35 id=5 name='Black Lion' secret_name='Trevor Challa'
```
-!!! tip
- We get `Black Lion` here too because although the age is not *strictly* less than `35` it is *equal* to `35`.
+/// tip
+
+We get `Black Lion` here too because although the age is not *strictly* less than `35` it is *equal* to `35`.
+
+///
### Benefits of Expressions
And with that the editor knows this code is actually fine, because this is a special **SQLModel** column.
-!!! tip
- That `col()` will come handy later, giving autocompletion to several other things we can do with these special **class attributes** for columns.
+/// tip
+
+That `col()` will come handy later, giving autocompletion to several other things we can do with these special **class attributes** for columns.
+
+But we'll get there later.
- But we'll get there later.
+///
## Recap
- search.suggest
- search.highlight
- content.tabs.link
+ - navigation.indexes
+ - content.tooltips
+ - navigation.path
+ - content.code.annotate
+ - content.code.copy
+ - content.code.select
+ # - navigation.tabs
icon:
repo: fontawesome/brands/github-alt
logo: img/icon-white.svg
- release-notes.md
markdown_extensions:
+- markdown.extensions.attr_list
+- markdown.extensions.tables
+- markdown.extensions.md_in_html
- toc:
permalink: true
-- markdown.extensions.codehilite:
- guess_lang: false
-- admonition
-- codehilite
-- extra
- pymdownx.superfences:
custom_fences:
- name: mermaid
class: mermaid
format: !!python/name:pymdownx.superfences.fence_code_format ''
-- pymdownx.tabbed:
- alternate_style: true
+- pymdownx.betterem
+- pymdownx.highlight
+- pymdownx.blocks.details
+- pymdownx.blocks.admonition:
+ types:
+ - note
+ - info
+ - tip
+ - warning
+ - danger
+- pymdownx.blocks.tab:
+ alternate_style: True
- mdx_include
extra:
projects / thirdparty / fastapi / sqlmodel.git / commitdiff
