sqlmodel/docs/tutorial/relationship-attributes/read-relationships.md

# Read Relationships

Now that we know how to connect data using **relationship Attributes**, let's see how to get and read the objects from a relationship.

## Select a Hero

First, add a function `select_heroes()` where we get a hero to start working with, and add that function to the `main()` function:

```Python hl_lines="3-7  14"
# Code above omitted 👆

{!./docs_src/tutorial/relationship_attributes/read_relationships/tutorial001.py[ln:96-100]!}

# Previous code here omitted 👈

{!./docs_src/tutorial/relationship_attributes/read_relationships/tutorial001.py[ln:110-113]!}

# Code below omitted 👇
```

<details>
<summary>👀 Full file preview</summary>

```Python
{!./docs_src/tutorial/relationship_attributes/read_relationships/tutorial001.py!}
```

</details>

## Select the Related Team - Old Way

Now that we have a hero, we can get the team this hero belongs to.

With what we have learned **up to now**, we could use a `select()` statement, then execute it with `session.exec()`, and then get the `.first()` result, for example:

```Python hl_lines="9-12"
# Code above omitted 👆

{!./docs_src/tutorial/relationship_attributes/read_relationships/tutorial001.py[ln:96-105]!}

# Code below omitted 👇
```

<details>
<summary>👀 Full file preview</summary>

```Python
{!./docs_src/tutorial/relationship_attributes/read_relationships/tutorial001.py!}
```

</details>

## Get Relationship Team - New Way

But now that we have the **relationship attributes**, we can just access them, and **SQLModel** (actually SQLAlchemy) will go and fetch the correspoinding data from the database, and make it available in the attribute. ✨

So, the highlighted block above, has the same results as the block below:

```Python hl_lines="11"
# Code above omitted 👆

{!./docs_src/tutorial/relationship_attributes/read_relationships/tutorial001.py[ln:96-100]!}

        # Code from the previous example omitted 👈

{!./docs_src/tutorial/relationship_attributes/read_relationships/tutorial001.py[ln:107]!}

# Code below omitted 👇
```

<details>
<summary>👀 Full file preview</summary>

```Python
{!./docs_src/tutorial/relationship_attributes/read_relationships/tutorial001.py!}
```

</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.

    For example, here, **inside** a `with` block with a `Session` object.

## Get a List of Relationship Objects

And the same way, when we are working on the **many** side of the **one-to-many** relationship, we can get a list of of the related objects just by accessing the relationship attribute:

```Python hl_lines="9"
# Code above omitted 👆

{!./docs_src/tutorial/relationship_attributes/read_relationships/tutorial002.py[ln:96-102]!}

# Code below omitted 👇
```

<details>
<summary>👀 Full file preview</summary>

```Python
{!./docs_src/tutorial/relationship_attributes/read_relationships/tutorial002.py!}
```

</details>

That would print a list with all the heroes in the Preventers team:

<div class="termy">

```console
$ python app.py

// Automatically fetch the heroes
INFO Engine SELECT hero.id AS hero_id, hero.name AS hero_name, hero.secret_name AS hero_secret_name, hero.age AS hero_age, hero.team_id AS hero_team_id 
FROM hero 
WHERE ? = hero.team_id
INFO Engine [cached since 0.8774s ago] (2,)

// Print the list of Preventers
Preventers heroes: [
    Hero(name='Rusty-Man', age=48, id=2, secret_name='Tommy Sharp', team_id=2),
    Hero(name='Spider-Boy', age=None, id=3, secret_name='Pedro Parqueador', team_id=2),
    Hero(name='Tarantula', age=32, id=6, secret_name='Natalia Roman-on', team_id=2),
    Hero(name='Dr. Weird', age=36, id=7, secret_name='Steve Weird', team_id=2),
    Hero(name='Captain North America', age=93, id=8, secret_name='Esteban Rogelios', team_id=2)
]
```

</div>

## Recap

With **relationship attributes** you can use the power of common Python objects to easily access related data from the database. 😎