diff --git a/docs/en/docs/tutorial/sql-databases.md b/docs/en/docs/tutorial/sql-databases.md index cfa1c9073..b42e9ba2f 100644 --- a/docs/en/docs/tutorial/sql-databases.md +++ b/docs/en/docs/tutorial/sql-databases.md @@ -65,7 +65,7 @@ There are a few differences: * `Field(primary_key=True)` tells SQLModel that the `id` is the **primary key** in the SQL database (you can learn more about SQL primary keys in the SQLModel docs). - By having the type as `int | None`, SQLModel will know that this column should be an `INTEGER` in the SQL database and that it should be `NULLABLE`. + **Note:** We use `int | None` for the primary key field so that in Python code we can *create an object without an `id`* (`id=None`), assuming the database will *generate it when saving*. SQLModel understands that the database will provide the `id` and *defines the column as a non-null `INTEGER`* in the database schema. See SQLModel docs on primary keys for details. * `Field(index=True)` tells SQLModel that it should create a **SQL index** for this column, that would allow faster lookups in the database when reading data filtered by this column.