Let's imagine that you have your **backend** API in some domain.

And you have a **frontend** in another domain or in a different path of the same domain (or in a mobile application).

And you want to have a way for the frontend to authenticate with the backend, using a **username** and **password**.

We can use **OAuth2** to build that with **FastAPI**.

But `OAuth2PasswordRequestForm` is just a class dependency that you could have written yourself, or you could have declared `Form` parameters directly.

But as it's a common use case, it is provided by **FastAPI** directly, just to make it easier.

///

### Use the form data { #use-the-form-data }

/// tip

          And mentioned me to him:
        She gave me a good character,
          But said I could not swim.

        He sent them word I had not gone
          (We know it to be true):
        If she should push the matter on,
          What would become of you?

        I gave her one, they gave him two,
          You gave us three or more;
        They all returned from him to you,

	} else if len(stmt.Schema.PrimaryFields) != 1 {
		t.Errorf("should have only one primary field with embedded struct, but got %v", len(stmt.Schema.PrimaryFields))
	}

	for _, name := range []string{"user_id", "user_name", "user_email"} {
		if !DB.Migrator().HasColumn(&HNPost{}, name) {
			t.Errorf("should has prefixed column %v", name)
		}
	}

	// save embedded struct
	DB.Save(&HNPost{BasePost: BasePost{Title: "news"}})

// Some Android 5.0.x Samsung devices have bugs in JDK reflection APIs that cause
// getDeclaredField to throw a NoSuchFieldException when the field is definitely there.
// Since this class only needs CAS on one field, we can avoid this bug by extending AtomicReference
// instead of using an AtomicReferenceFieldUpdater. This reference stores Thread instances
// and DONE/INTERRUPTED - they have a common ancestor of Runnable.

        loadLayout(reader, false);
    }

    public void save() throws IOException {
        save(this.location);
    }

    public void save(Path location) throws IOException {
        try (OutputStream os = Files.newOutputStream(location)) {
            save(os);
        }
    }

    public void save(OutputStream os) throws IOException {
        save(new OutputStreamWriter(os, DEFAULT_ENCODING));
    }

        loadLayout(reader, false);
    }

    public void save() throws IOException {
        save(this.location);
    }

    public void save(Path location) throws IOException {
        try (OutputStream os = Files.newOutputStream(location)) {
            save(os);
        }
    }

    public void save(OutputStream os) throws IOException {
        save(new OutputStreamWriter(os, DEFAULT_ENCODING));
    }

    assertThat(keySet).containsExactly(1, 3, 6, 8);

    // get fails to save 1, put saves 3
    cache.asMap().put(3, -3);
    getAll(cache, asList(1));
    CacheTesting.drainRecencyQueues(cache);
    ticker.advance(1, MILLISECONDS);
    assertThat(keySet).containsExactly(6, 8, 3);

    // get(K, Callable) fails to save 8, replace saves 6
    cache.asMap().replace(6, -6);

	}
}

func TestSelect(t *testing.T) {
	user := User{Name: "SelectUser1"}
	DB.Save(&user)

	var result User
	DB.Where("name = ?", user.Name).Select("name").Find(&result)
	if result.ID != 0 {
		t.Errorf("Should not have ID because only selected name, %+v", result.ID)
	}

	if user.Name != result.Name {
		t.Errorf("Should have user Name when selected it")
	}

	var result2 User

	. "gorm.io/gorm/utils/tests"
)

func TestRow(t *testing.T) {
	user1 := User{Name: "RowUser1", Age: 1}
	user2 := User{Name: "RowUser2", Age: 10}
	user3 := User{Name: "RowUser3", Age: 20}
	DB.Save(&user1).Save(&user2).Save(&user3)

	row := DB.Table("users").Where("name = ?", user2.Name).Select("age").Row()

	var age int64
	if err := row.Scan(&age); err != nil {
		t.Fatalf("Failed to scan age, got %v", err)
	}