diff --git a/src/arcaea_offline/database/models/v5/__init__.py b/src/arcaea_offline/database/models/v5/__init__.py
new file mode 100644
index 0000000..2865160
--- /dev/null
+++ b/src/arcaea_offline/database/models/v5/__init__.py
@@ -0,0 +1,38 @@
+from .arcaea import (
+    Chart,
+    ChartInfo,
+    Difficulty,
+    DifficultyLocalized,
+    Pack,
+    PackLocalized,
+    Song,
+    SongLocalized,
+    SongSearchWord,
+)
+from .base import ModelsV5Base, ModelsV5ViewBase
+from .config import Property
+from .play_results import (
+    CalculatedPotential,
+    PlayResult,
+    PlayResultBest,
+    PlayResultCalculated,
+)
+
+__all__ = [
+    "CalculatedPotential",
+    "Chart",
+    "ChartInfo",
+    "Difficulty",
+    "DifficultyLocalized",
+    "ModelsV5Base",
+    "ModelsV5ViewBase",
+    "Pack",
+    "PackLocalized",
+    "PlayResult",
+    "PlayResultBest",
+    "PlayResultCalculated",
+    "Property",
+    "Song",
+    "SongLocalized",
+    "SongSearchWord",
+]
diff --git a/src/arcaea_offline/database/models/v5/arcaea.py b/src/arcaea_offline/database/models/v5/arcaea.py
new file mode 100644
index 0000000..67835b5
--- /dev/null
+++ b/src/arcaea_offline/database/models/v5/arcaea.py
@@ -0,0 +1,275 @@
+from typing import List, Optional
+
+from sqlalchemy import ForeignKey, and_, func, select
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+from sqlalchemy_utils import create_view
+
+from arcaea_offline.constants.enums import ArcaeaRatingClass, ArcaeaSongSide
+
+from .base import ModelsV5Base, ModelsV5ViewBase, ReprHelper
+
+__all__ = [
+    "Chart",
+    "ChartInfo",
+    "Difficulty",
+    "DifficultyLocalized",
+    "Pack",
+    "PackLocalized",
+    "Song",
+    "SongLocalized",
+]
+
+
+class Pack(ModelsV5Base, ReprHelper):
+    __tablename__ = "packs"
+
+    id: Mapped[str] = mapped_column(primary_key=True)
+    name: Mapped[str]
+    description: Mapped[Optional[str]]
+
+    songs: Mapped[List["Song"]] = relationship(back_populates="pack", viewonly=True)
+    localized_objects: Mapped[List["PackLocalized"]] = relationship(
+        back_populates="parent", viewonly=True
+    )
+
+
+class PackLocalized(ModelsV5Base, ReprHelper):
+    __tablename__ = "packs_localized"
+
+    pkid: Mapped[int] = mapped_column(primary_key=True)
+    id: Mapped[str] = mapped_column(
+        ForeignKey(Pack.id, onupdate="CASCADE", ondelete="NO ACTION")
+    )
+    lang: Mapped[str]
+    name: Mapped[Optional[str]]
+    description: Mapped[Optional[str]]
+
+    parent: Mapped[Pack] = relationship(viewonly=True)
+
+
+class Song(ModelsV5Base, ReprHelper):
+    __tablename__ = "songs"
+
+    idx: Mapped[int]
+    id: Mapped[str] = mapped_column(primary_key=True)
+    title: Mapped[str]
+    artist: Mapped[str]
+    pack_id: Mapped[str] = mapped_column(
+        ForeignKey(Pack.id, onupdate="CASCADE", ondelete="NO ACTION")
+    )
+    bpm: Mapped[Optional[str]]
+    bpm_base: Mapped[Optional[float]]
+    audio_preview: Mapped[Optional[int]]
+    audio_preview_end: Mapped[Optional[int]]
+    side: Mapped[Optional[ArcaeaSongSide]]
+    version: Mapped[Optional[str]]
+    date: Mapped[Optional[int]]
+    bg: Mapped[Optional[str]]
+    bg_inverse: Mapped[Optional[str]]
+    bg_day: Mapped[Optional[str]]
+    bg_night: Mapped[Optional[str]]
+    source: Mapped[Optional[str]]
+    source_copyright: Mapped[Optional[str]]
+
+    pack: Mapped[Pack] = relationship(viewonly=True)
+    difficulties: Mapped[List["Difficulty"]] = relationship(
+        back_populates="song", viewonly=True
+    )
+    localized_objects: Mapped[List["SongLocalized"]] = relationship(
+        back_populates="parent", viewonly=True
+    )
+
+    @property
+    def charts_info(self):
+        return [d.chart_info for d in self.difficulties if d.chart_info is not None]
+
+
+class SongLocalized(ModelsV5Base, ReprHelper):
+    __tablename__ = "songs_localized"
+
+    pkid: Mapped[int] = mapped_column(primary_key=True)
+    id: Mapped[str] = mapped_column(
+        ForeignKey(Song.id, onupdate="CASCADE", ondelete="NO ACTION")
+    )
+    lang: Mapped[str]
+    title: Mapped[Optional[str]]
+    source: Mapped[Optional[str]]
+
+    parent: Mapped[Song] = relationship(
+        back_populates="localized_objects", viewonly=True
+    )
+
+
+class SongSearchWord(ModelsV5Base, ReprHelper):
+    __tablename__ = "songs_search_words"
+
+    pkid: Mapped[int] = mapped_column(primary_key=True)
+    id: Mapped[str] = mapped_column(
+        ForeignKey(Song.id, onupdate="CASCADE", ondelete="NO ACTION")
+    )
+    lang: Mapped[str]
+    type: Mapped[int] = mapped_column(comment="1: title, 2: artist")
+    value: Mapped[str]
+
+
+class Difficulty(ModelsV5Base, ReprHelper):
+    __tablename__ = "difficulties"
+
+    song_id: Mapped[str] = mapped_column(
+        ForeignKey(Song.id, onupdate="CASCADE", ondelete="NO ACTION"),
+        primary_key=True,
+    )
+    rating_class: Mapped[ArcaeaRatingClass] = mapped_column(primary_key=True)
+    rating: Mapped[int]
+    rating_plus: Mapped[bool]
+    chart_designer: Mapped[Optional[str]]
+    jacket_desginer: Mapped[Optional[str]]
+    audio_override: Mapped[bool] = mapped_column(default=False)
+    jacket_override: Mapped[bool] = mapped_column(default=False)
+    jacket_night: Mapped[Optional[str]]
+    title: Mapped[Optional[str]]
+    artist: Mapped[Optional[str]]
+    bg: Mapped[Optional[str]]
+    bg_inverse: Mapped[Optional[str]]
+    bpm: Mapped[Optional[str]]
+    bpm_base: Mapped[Optional[float]]
+    version: Mapped[Optional[str]]
+    date: Mapped[Optional[int]]
+
+    song: Mapped[Song] = relationship(back_populates="difficulties", viewonly=True)
+    chart_info: Mapped[Optional["ChartInfo"]] = relationship(
+        primaryjoin=(
+            "and_(Difficulty.song_id==ChartInfo.song_id, "
+            "Difficulty.rating_class==ChartInfo.rating_class)"
+        ),
+        viewonly=True,
+    )
+    localized_objects: Mapped[List["DifficultyLocalized"]] = relationship(
+        primaryjoin=(
+            "and_(Difficulty.song_id==DifficultyLocalized.song_id, "
+            "Difficulty.rating_class==DifficultyLocalized.rating_class)"
+        ),
+        viewonly=True,
+    )
+
+
+class DifficultyLocalized(ModelsV5Base, ReprHelper):
+    __tablename__ = "difficulties_localized"
+
+    pkid: Mapped[int] = mapped_column(primary_key=True)
+    song_id: Mapped[str] = mapped_column(
+        ForeignKey(Difficulty.song_id, onupdate="CASCADE", ondelete="NO ACTION")
+    )
+    rating_class: Mapped[ArcaeaRatingClass] = mapped_column(
+        ForeignKey(Difficulty.rating_class, onupdate="CASCADE", ondelete="NO ACTION")
+    )
+    lang: Mapped[str]
+    title: Mapped[Optional[str]]
+    artist: Mapped[Optional[str]]
+
+    parent: Mapped[Difficulty] = relationship(
+        primaryjoin=and_(
+            Difficulty.song_id == song_id, Difficulty.rating_class == rating_class
+        ),
+        viewonly=True,
+    )
+
+
+class ChartInfo(ModelsV5Base, ReprHelper):
+    __tablename__ = "charts_info"
+
+    song_id: Mapped[str] = mapped_column(
+        ForeignKey(Difficulty.song_id, onupdate="CASCADE", ondelete="NO ACTION"),
+        primary_key=True,
+    )
+    rating_class: Mapped[ArcaeaRatingClass] = mapped_column(
+        ForeignKey(Difficulty.rating_class, onupdate="CASCADE", ondelete="NO ACTION"),
+        primary_key=True,
+    )
+    constant: Mapped[int] = mapped_column(
+        comment="real_constant * 10. For example, Crimson Throne [FTR] is 10.4, then store 104."
+    )
+    notes: Mapped[Optional[int]]
+
+    difficulty: Mapped[Difficulty] = relationship(
+        primaryjoin=and_(
+            Difficulty.song_id == song_id, Difficulty.rating_class == rating_class
+        ),
+        viewonly=True,
+    )
+
+
+class Chart(ModelsV5ViewBase, ReprHelper):
+    __tablename__ = "charts"
+
+    song_idx: Mapped[int]
+    song_id: Mapped[str]
+    rating_class: Mapped[ArcaeaRatingClass]
+    rating: Mapped[int]
+    rating_plus: Mapped[bool]
+    title: Mapped[str]
+    artist: Mapped[str]
+    pack_id: Mapped[str]
+    bpm: Mapped[Optional[str]]
+    bpm_base: Mapped[Optional[float]]
+    audio_preview: Mapped[Optional[int]]
+    audio_preview_end: Mapped[Optional[int]]
+    side: Mapped[Optional[int]]
+    version: Mapped[Optional[str]]
+    date: Mapped[Optional[int]]
+    bg: Mapped[Optional[str]]
+    bg_inverse: Mapped[Optional[str]]
+    bg_day: Mapped[Optional[str]]
+    bg_night: Mapped[Optional[str]]
+    source: Mapped[Optional[str]]
+    source_copyright: Mapped[Optional[str]]
+    chart_designer: Mapped[Optional[str]]
+    jacket_desginer: Mapped[Optional[str]]
+    audio_override: Mapped[bool]
+    jacket_override: Mapped[bool]
+    jacket_night: Mapped[Optional[str]]
+    constant: Mapped[int]
+    notes: Mapped[Optional[int]]
+
+    __table__ = create_view(
+        name=__tablename__,
+        selectable=select(
+            Song.idx.label("song_idx"),
+            Difficulty.song_id,
+            Difficulty.rating_class,
+            Difficulty.rating,
+            Difficulty.rating_plus,
+            func.coalesce(Difficulty.title, Song.title).label("title"),
+            func.coalesce(Difficulty.artist, Song.artist).label("artist"),
+            Song.pack_id,
+            func.coalesce(Difficulty.bpm, Song.bpm).label("bpm"),
+            func.coalesce(Difficulty.bpm_base, Song.bpm_base).label("bpm_base"),
+            Song.audio_preview,
+            Song.audio_preview_end,
+            Song.side,
+            func.coalesce(Difficulty.version, Song.version).label("version"),
+            func.coalesce(Difficulty.date, Song.date).label("date"),
+            func.coalesce(Difficulty.bg, Song.bg).label("bg"),
+            func.coalesce(Difficulty.bg_inverse, Song.bg_inverse).label("bg_inverse"),
+            Song.bg_day,
+            Song.bg_night,
+            Song.source,
+            Song.source_copyright,
+            Difficulty.chart_designer,
+            Difficulty.jacket_desginer,
+            Difficulty.audio_override,
+            Difficulty.jacket_override,
+            Difficulty.jacket_night,
+            ChartInfo.constant,
+            ChartInfo.notes,
+        )
+        .select_from(Difficulty)
+        .join(
+            ChartInfo,
+            (Difficulty.song_id == ChartInfo.song_id)
+            & (Difficulty.rating_class == ChartInfo.rating_class),
+        )
+        .join(Song, Difficulty.song_id == Song.id),
+        metadata=ModelsV5ViewBase.metadata,
+        cascade_on_drop=False,
+    )
diff --git a/src/arcaea_offline/database/models/v5/base.py b/src/arcaea_offline/database/models/v5/base.py
new file mode 100644
index 0000000..516d0b3
--- /dev/null
+++ b/src/arcaea_offline/database/models/v5/base.py
@@ -0,0 +1,62 @@
+from datetime import datetime
+
+from sqlalchemy.orm import DeclarativeBase
+from sqlalchemy.orm.exc import DetachedInstanceError
+
+from arcaea_offline.constants.enums import (
+    ArcaeaPlayResultClearType,
+    ArcaeaPlayResultModifier,
+    ArcaeaRatingClass,
+    ArcaeaSongSide,
+)
+
+from .._custom_types import DbIntEnum, TZDateTime
+
+TYPE_ANNOTATION_MAP = {
+    datetime: TZDateTime,
+    ArcaeaRatingClass: DbIntEnum(ArcaeaRatingClass),
+    ArcaeaSongSide: DbIntEnum(ArcaeaSongSide),
+    ArcaeaPlayResultClearType: DbIntEnum(ArcaeaPlayResultClearType),
+    ArcaeaPlayResultModifier: DbIntEnum(ArcaeaPlayResultModifier),
+}
+
+
+class ModelsV5Base(DeclarativeBase):
+    type_annotation_map = TYPE_ANNOTATION_MAP
+
+
+class ModelsV5ViewBase(DeclarativeBase):
+    type_annotation_map = TYPE_ANNOTATION_MAP
+
+
+class ReprHelper:
+    # pylint: disable=no-member
+
+    def _repr(self, **kwargs) -> str:
+        """
+        Helper for __repr__
+
+        https://stackoverflow.com/a/55749579/16484891
+
+        CC BY-SA 4.0
+        """
+        field_strings = []
+        at_least_one_attached_attribute = False
+        for key, field in kwargs.items():
+            try:
+                field_strings.append(f"{key}={field!r}")
+            except DetachedInstanceError:
+                field_strings.append(f"{key}=DetachedInstanceError")
+            else:
+                at_least_one_attached_attribute = True
+
+        if at_least_one_attached_attribute:
+            return f"<{self.__class__.__name__}({', '.join(field_strings)})>"
+        return f"<{self.__class__.__name__} {id(self)}>"
+
+    def __repr__(self):
+        if isinstance(self, DeclarativeBase):
+            return self._repr(
+                **{c.key: getattr(self, c.key) for c in self.__table__.columns}
+            )
+        return super().__repr__()
diff --git a/src/arcaea_offline/database/models/v5/config.py b/src/arcaea_offline/database/models/v5/config.py
new file mode 100644
index 0000000..ca5a339
--- /dev/null
+++ b/src/arcaea_offline/database/models/v5/config.py
@@ -0,0 +1,12 @@
+from sqlalchemy.orm import Mapped, mapped_column
+
+from .base import ModelsV5Base, ReprHelper
+
+__all__ = ["Property"]
+
+
+class Property(ModelsV5Base, ReprHelper):
+    __tablename__ = "properties"
+
+    key: Mapped[str] = mapped_column(primary_key=True)
+    value: Mapped[str] = mapped_column()
diff --git a/src/arcaea_offline/database/models/v5/play_results.py b/src/arcaea_offline/database/models/v5/play_results.py
new file mode 100644
index 0000000..51d610f
--- /dev/null
+++ b/src/arcaea_offline/database/models/v5/play_results.py
@@ -0,0 +1,197 @@
+from datetime import datetime, timezone
+from typing import Optional
+
+from sqlalchemy import ForeignKey, and_, case, func, inspect, select, text
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+from sqlalchemy_utils import create_view
+
+from arcaea_offline.constants.enums import (
+    ArcaeaPlayResultClearType,
+    ArcaeaPlayResultModifier,
+    ArcaeaRatingClass,
+)
+
+from .arcaea import ChartInfo, Difficulty
+from .base import ModelsV5Base, ModelsV5ViewBase, ReprHelper
+
+__all__ = [
+    "CalculatedPotential",
+    "PlayResult",
+    "PlayResultBest",
+    "PlayResultCalculated",
+]
+
+
+class PlayResult(ModelsV5Base, ReprHelper):
+    __tablename__ = "play_results"
+
+    id: Mapped[int] = mapped_column(autoincrement=True, primary_key=True)
+    song_id: Mapped[str] = mapped_column(
+        ForeignKey(Difficulty.song_id, onupdate="CASCADE", ondelete="NO ACTION"),
+        index=True,
+    )
+    rating_class: Mapped[ArcaeaRatingClass] = mapped_column(
+        ForeignKey(Difficulty.rating_class, onupdate="CASCADE", ondelete="NO ACTION"),
+        index=True,
+    )
+    score: Mapped[int]
+    pure: Mapped[Optional[int]]
+    far: Mapped[Optional[int]]
+    lost: Mapped[Optional[int]]
+    date: Mapped[Optional[datetime]] = mapped_column(
+        default=lambda: datetime.now(timezone.utc)
+    )
+    max_recall: Mapped[Optional[int]]
+    modifier: Mapped[Optional[ArcaeaPlayResultModifier]]
+    clear_type: Mapped[Optional[ArcaeaPlayResultClearType]]
+    comment: Mapped[Optional[str]]
+
+    difficulty: Mapped[Difficulty] = relationship(
+        primaryjoin=and_(
+            song_id == Difficulty.song_id,
+            rating_class == Difficulty.rating_class,
+        ),
+        viewonly=True,
+    )
+
+
+# How to create an SQL View with SQLAlchemy?
+# https://stackoverflow.com/a/53253105/16484891
+# CC BY-SA 4.0
+
+
+class PlayResultCalculated(ModelsV5ViewBase, ReprHelper):
+    __tablename__ = "play_results_calculated"
+
+    id: Mapped[int]
+    song_id: Mapped[str]
+    rating_class: Mapped[ArcaeaRatingClass]
+    score: Mapped[int]
+    pure: Mapped[Optional[int]]
+    shiny_pure: Mapped[Optional[int]]
+    far: Mapped[Optional[int]]
+    lost: Mapped[Optional[int]]
+    date: Mapped[Optional[datetime]]
+    max_recall: Mapped[Optional[int]]
+    modifier: Mapped[Optional[ArcaeaPlayResultModifier]]
+    clear_type: Mapped[Optional[ArcaeaPlayResultClearType]]
+    potential: Mapped[float]
+    comment: Mapped[Optional[str]]
+
+    __table__ = create_view(
+        name=__tablename__,
+        selectable=select(
+            PlayResult.id,
+            Difficulty.song_id,
+            Difficulty.rating_class,
+            PlayResult.score,
+            PlayResult.pure,
+            (
+                case(
+                    (
+                        (
+                            ChartInfo.notes.is_not(None)
+                            & PlayResult.pure.is_not(None)
+                            & PlayResult.far.is_not(None)
+                            & (ChartInfo.notes != 0)
+                        ),
+                        PlayResult.score
+                        - func.floor(
+                            (PlayResult.pure * 10000000.0 / ChartInfo.notes)
+                            + (PlayResult.far * 0.5 * 10000000.0 / ChartInfo.notes)
+                        ),
+                    ),
+                    else_=text("NULL"),
+                )
+            ).label("shiny_pure"),
+            PlayResult.far,
+            PlayResult.lost,
+            PlayResult.date,
+            PlayResult.max_recall,
+            PlayResult.modifier,
+            PlayResult.clear_type,
+            case(
+                (PlayResult.score >= 10000000, ChartInfo.constant / 10.0 + 2),  # noqa: PLR2004
+                (
+                    PlayResult.score >= 9800000,  # noqa: PLR2004
+                    ChartInfo.constant / 10.0
+                    + 1
+                    + (PlayResult.score - 9800000) / 200000.0,
+                ),
+                else_=func.max(
+                    (ChartInfo.constant / 10.0)
+                    + (PlayResult.score - 9500000) / 300000.0,
+                    0,
+                ),
+            ).label("potential"),
+            PlayResult.comment,
+        )
+        .select_from(Difficulty)
+        .join(
+            ChartInfo,
+            (Difficulty.song_id == ChartInfo.song_id)
+            & (Difficulty.rating_class == ChartInfo.rating_class),
+        )
+        .join(
+            PlayResult,
+            (Difficulty.song_id == PlayResult.song_id)
+            & (Difficulty.rating_class == PlayResult.rating_class),
+        ),
+        metadata=ModelsV5ViewBase.metadata,
+        cascade_on_drop=False,
+    )
+
+
+class PlayResultBest(ModelsV5ViewBase, ReprHelper):
+    __tablename__ = "play_results_best"
+
+    id: Mapped[int]
+    song_id: Mapped[str]
+    rating_class: Mapped[int]
+    score: Mapped[int]
+    pure: Mapped[Optional[int]]
+    shiny_pure: Mapped[Optional[int]]
+    far: Mapped[Optional[int]]
+    lost: Mapped[Optional[int]]
+    date: Mapped[Optional[datetime]]
+    max_recall: Mapped[Optional[int]]
+    modifier: Mapped[Optional[ArcaeaPlayResultModifier]]
+    clear_type: Mapped[Optional[ArcaeaPlayResultClearType]]
+    potential: Mapped[float]
+    comment: Mapped[Optional[str]]
+
+    __table__ = create_view(
+        name=__tablename__,
+        selectable=select(
+            *[
+                col
+                for col in inspect(PlayResultCalculated).columns
+                if col.name != "potential"
+            ],
+            func.max(PlayResultCalculated.potential).label("potential"),
+        )
+        .select_from(PlayResultCalculated)
+        .group_by(PlayResultCalculated.song_id, PlayResultCalculated.rating_class)
+        .order_by(PlayResultCalculated.potential.desc()),
+        metadata=ModelsV5ViewBase.metadata,
+        cascade_on_drop=False,
+    )
+
+
+class CalculatedPotential(ModelsV5ViewBase, ReprHelper):
+    __tablename__ = "calculated_potential"
+
+    b30: Mapped[float]
+
+    _select_bests_subquery = (
+        select(PlayResultBest.potential.label("b30_sum"))
+        .order_by(PlayResultBest.potential.desc())
+        .limit(30)
+        .subquery()
+    )
+    __table__ = create_view(
+        name=__tablename__,
+        selectable=select(func.avg(_select_bests_subquery.c.b30_sum).label("b30")),
+        metadata=ModelsV5ViewBase.metadata,
+        cascade_on_drop=False,
+    )
diff --git a/tests/db/models/v5/__init__.py b/tests/db/models/v5/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/db/models/v5/relationships/__init__.py b/tests/db/models/v5/relationships/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/db/models/v5/relationships/test_common.py b/tests/db/models/v5/relationships/test_common.py
new file mode 100644
index 0000000..604240d
--- /dev/null
+++ b/tests/db/models/v5/relationships/test_common.py
@@ -0,0 +1,143 @@
+"""
+Database model v5 common relationships
+
+┌──────┐   ┌──────┐   ┌────────────┐   ┌────────────┐
+│ Pack ◄───► Song ◄───► Difficulty ◄───┤ PlayResult │
+└──────┘   └──┬───┘   └─────▲──────┘   └────────────┘
+              │             │
+              │       ┌─────▼─────┐
+              └───────► ChartInfo │
+                      └───────────┘
+"""
+
+from arcaea_offline.constants.enums import ArcaeaRatingClass
+from arcaea_offline.database.models.v5 import (
+    ChartInfo,
+    Difficulty,
+    ModelsV5Base,
+    Pack,
+    PlayResult,
+    Song,
+)
+
+
+class TestSongRelationships:
+    @staticmethod
+    def init_db(session):
+        ModelsV5Base.metadata.create_all(session.bind)
+
+    def test_relationships(self, db_session):
+        self.init_db(db_session)
+
+        song_id = "test_song"
+        title_en = "Test Lorem Ipsum"
+        artist_en = "Test Artist"
+
+        pack = Pack(
+            id="test_pack",
+            name="Test Pack",
+            description="This is a test pack.",
+        )
+
+        song = Song(
+            idx=1,
+            id=song_id,
+            title=title_en,
+            artist=artist_en,
+            pack_id=pack.id,
+        )
+
+        difficulty_pst = Difficulty(
+            song_id=song.id,
+            rating_class=ArcaeaRatingClass.PAST,
+            rating=2,
+            rating_plus=False,
+        )
+        chart_info_pst = ChartInfo(
+            song_id=song.id,
+            rating_class=ArcaeaRatingClass.PAST,
+            constant=20,
+            notes=200,
+        )
+
+        difficulty_prs = Difficulty(
+            song_id=song.id,
+            rating_class=ArcaeaRatingClass.PRESENT,
+            rating=7,
+            rating_plus=True,
+        )
+        chart_info_prs = ChartInfo(
+            song_id=song.id,
+            rating_class=ArcaeaRatingClass.PRESENT,
+            constant=78,
+            notes=780,
+        )
+
+        difficulty_ftr = Difficulty(
+            song_id=song.id,
+            rating_class=ArcaeaRatingClass.FUTURE,
+            rating=10,
+            rating_plus=True,
+        )
+        chart_info_ftr = ChartInfo(
+            song_id=song.id,
+            rating_class=ArcaeaRatingClass.FUTURE,
+            constant=109,
+            notes=1090,
+        )
+
+        difficulty_etr = Difficulty(
+            song_id=song.id,
+            rating_class=ArcaeaRatingClass.ETERNAL,
+            rating=9,
+            rating_plus=True,
+        )
+
+        play_result_ftr = PlayResult(
+            song_id=song.id,
+            rating_class=ArcaeaRatingClass.FUTURE,
+            score=123456,
+        )
+
+        db_session.add_all(
+            [
+                pack,
+                song,
+                difficulty_pst,
+                chart_info_pst,
+                difficulty_prs,
+                chart_info_prs,
+                difficulty_ftr,
+                chart_info_ftr,
+                difficulty_etr,
+                play_result_ftr,
+            ]
+        )
+        db_session.commit()
+
+        assert pack.songs == [song]
+
+        assert song.pack == pack
+        assert song.difficulties == [
+            difficulty_pst,
+            difficulty_prs,
+            difficulty_ftr,
+            difficulty_etr,
+        ]
+        assert song.charts_info == [chart_info_pst, chart_info_prs, chart_info_ftr]
+
+        assert difficulty_pst.song == song
+        assert difficulty_prs.song == song
+        assert difficulty_ftr.song == song
+        assert difficulty_etr.song == song
+
+        assert difficulty_pst.chart_info == chart_info_pst
+        assert difficulty_prs.chart_info == chart_info_prs
+        assert difficulty_ftr.chart_info == chart_info_ftr
+        assert difficulty_etr.chart_info is None
+
+        assert chart_info_pst.difficulty == difficulty_pst
+        assert chart_info_prs.difficulty == difficulty_prs
+        assert chart_info_ftr.difficulty == difficulty_ftr
+
+        assert play_result_ftr.difficulty == difficulty_ftr
diff --git a/tests/db/models/v5/relationships/test_pack.py b/tests/db/models/v5/relationships/test_pack.py
new file mode 100644
index 0000000..d6912e6
--- /dev/null
+++ b/tests/db/models/v5/relationships/test_pack.py
@@ -0,0 +1,69 @@
+"""
+Database model v5 relationships
+
+Pack <> PackLocalized
+"""
+
+from arcaea_offline.constants.enums import ArcaeaLanguage
+from arcaea_offline.database.models.v5 import ModelsV5Base, Pack, PackLocalized
+
+
+class TestPackRelationships:
+    @staticmethod
+    def init_db(session):
+        ModelsV5Base.metadata.create_all(session.bind)
+
+    def test_localized_objects(self, db_session):
+        self.init_db(db_session)
+
+        pack_id = "test_pack"
+        name_en = "Test Pack"
+        description_en = "Travel through common database models\nfrom the unpopular framework 'Arcaea Offline'\ntogether with an ordinary partner '∅'."
+
+        pack = Pack(
+            id=pack_id,
+            name=name_en,
+            description=description_en,
+        )
+
+        pkid_ja = 1
+        description_ja = "普通のパートナー「∅」と一緒に、\n不人気フレームワーク「Arcaea Offline」より、\n一般的なデータベース・モデルを通過する。"
+        pack_localized_ja = PackLocalized(
+            pkid=pkid_ja,
+            id=pack_id,
+            lang=ArcaeaLanguage.JA.value,
+            name=None,
+            description=description_ja,
+        )
+
+        pkid_zh_hans = 2
+        description_zh_hans = "与平凡的「∅」一起，\n在没人用的「Arcaea Offline」框架里，\n一同探索随处可见的数据库模型。"
+        pack_localized_zh_hans = PackLocalized(
+            pkid=pkid_zh_hans,
+            id=pack_id,
+            lang=ArcaeaLanguage.ZH_HANS.value,
+            name=None,
+            description=description_zh_hans,
+        )
+
+        db_session.add_all([pack, pack_localized_ja])
+        db_session.commit()
+
+        assert len(pack.localized_objects) == len([pack_localized_ja])
+
+        assert pack_localized_ja.parent.description == pack.description
+
+        # relationships should be viewonly
+        new_pack = Pack(
+            id=f"{pack_id}_new",
+            name="NEW",
+            description="new new pack",
+        )
+        db_session.add(new_pack)
+
+        pack_localized_ja.parent = new_pack
+        pack.localized_objects.append(pack_localized_zh_hans)
+        db_session.commit()
+
+        assert pack_localized_ja.parent == pack
+        assert len(pack.localized_objects) == 1
diff --git a/tests/db/models/v5/test_chart.py b/tests/db/models/v5/test_chart.py
new file mode 100644
index 0000000..ce62fd6
--- /dev/null
+++ b/tests/db/models/v5/test_chart.py
@@ -0,0 +1,110 @@
+"""
+Database models v5
+
+Chart functionalities
+- basic data handling
+- Difficulty song info overriding
+"""
+
+from arcaea_offline.constants.enums.arcaea import ArcaeaRatingClass
+from arcaea_offline.database.models.v5 import (
+    Chart,
+    ChartInfo,
+    Difficulty,
+    ModelsV5Base,
+    ModelsV5ViewBase,
+    Pack,
+    Song,
+)
+
+
+class TestChart:
+    def init_db(self, session):
+        ModelsV5Base.metadata.create_all(session.bind)
+        ModelsV5ViewBase.metadata.create_all(session.bind)
+
+    def test_basic(self, db_session):
+        self.init_db(db_session)
+
+        pack_id = "test_pack"
+        song_id = "test_song"
+        rating_class = ArcaeaRatingClass.FUTURE
+
+        pack = Pack(id=pack_id, name="Test Pack")
+        song = Song(
+            idx=2,
+            id=song_id,
+            title="~TEST~",
+            artist="~test~",
+            pack_id=pack_id,
+        )
+        difficulty = Difficulty(
+            song_id=song_id,
+            rating_class=rating_class,
+            rating=9,
+            rating_plus=True,
+        )
+        chart_info = ChartInfo(
+            song_id=song_id,
+            rating_class=rating_class,
+            constant=98,
+            notes=980,
+        )
+        db_session.add_all([pack, song, difficulty, chart_info])
+
+        chart: Chart = (
+            db_session.query(Chart)
+            .where((Chart.song_id == song_id) & (Chart.rating_class == rating_class))
+            .one()
+        )
+
+        # `song_id` and `rating_class` are guarded by the WHERE clause above
+        assert chart.song_idx == song.idx
+        assert chart.title == song.title
+        assert chart.artist == song.artist
+        assert chart.pack_id == song.pack_id
+        assert chart.rating == difficulty.rating
+        assert chart.rating_plus == difficulty.rating_plus
+        assert chart.constant == chart_info.constant
+        assert chart.notes == chart_info.notes
+
+    def test_difficulty_override(self, db_session):
+        self.init_db(db_session)
+
+        pack_id = "test_pack"
+        song_id = "test_song"
+        rating_class = ArcaeaRatingClass.FUTURE
+
+        pack = Pack(id=pack_id, name="Test Pack")
+        song = Song(
+            idx=2,
+            id=song_id,
+            title="~TEST~",
+            artist="~test~",
+            pack_id=pack_id,
+        )
+        difficulty = Difficulty(
+            song_id=song_id,
+            rating_class=rating_class,
+            rating=9,
+            rating_plus=True,
+            title="~TEST DIFF~",
+            artist="~diff~",
+        )
+        chart_info = ChartInfo(
+            song_id=song_id,
+            rating_class=rating_class,
+            constant=98,
+            notes=980,
+        )
+        db_session.add_all([pack, song, difficulty, chart_info])
+
+        chart: Chart = (
+            db_session.query(Chart)
+            .where((Chart.song_id == song_id) & (Chart.rating_class == rating_class))
+            .one()
+        )
+
+        assert chart.song_idx == song.idx
+        assert chart.title == difficulty.title
+        assert chart.artist == difficulty.artist