diff --git a/app/database.py b/app/database.py
index 0127fb0..0eec57d 100644
--- a/app/database.py
+++ b/app/database.py
@@ -19,7 +19,7 @@ from collections.abc import AsyncGenerator
 from pathlib import PurePath
 from typing import Final
 
-from sqlalchemy import BigInteger, ForeignKey, String, Text
+from sqlalchemy import BigInteger, ForeignKey, MetaData, String, Text, UniqueConstraint
 from sqlalchemy.ext.asyncio import (
     AsyncAttrs,
     AsyncEngine,
@@ -27,7 +27,12 @@ from sqlalchemy.ext.asyncio import (
     async_sessionmaker,
     create_async_engine,
 )
-from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, relationship
+from sqlalchemy.orm import (
+    Mapped,
+    declarative_base,
+    mapped_column,
+    relationship,
+)
 
 DB_PATH: Final[PurePath] = PurePath(__file__).parent.parent / "db.sqlite3"
 
@@ -39,6 +44,16 @@ async_session_maker: Final[async_sessionmaker[AsyncSession]] = async_sessionmake
     engine, expire_on_commit=False, autoflush=False, autocommit=False
 )
 
+metadata = MetaData(
+    naming_convention={
+        "ix": "ix_%(table_name)s_%(column_0_N_name)s ",
+        "uq": "uq_%(table_name)s_%(column_0_N_name)s ",
+        "ck": "ck_%(table_name)s_%(constraint_name)s ",
+        "fk": "fk_%(table_name)s_%(column_0_N_name)s_%(referred_table_name)s",
+        "pk": "pk_%(table_name)s",
+    }
+)
+
 
 async def get_async_session() -> AsyncGenerator[AsyncSession, None]:
     """Get an async session."""
@@ -46,10 +61,7 @@ async def get_async_session() -> AsyncGenerator[AsyncSession, None]:
         yield session
 
 
-class Base(AsyncAttrs, DeclarativeBase):
-    """Declarative base for database models."""
-
-    pass
+Base = declarative_base(metadata=metadata, cls=AsyncAttrs)
 
 
 class Repo(Base):
@@ -66,6 +78,7 @@ class Repo(Base):
     dependencies: Mapped[list["Dependency"]] = relationship(
         "Dependency", secondary="repo_dependency", back_populates="repos"
     )
+    __table_args__ = (UniqueConstraint("url", "source_graph_repo_id"),)
 
 
 class Dependency(Base):
diff --git a/app/source_graph/mapper.py b/app/source_graph/mapper.py
index b69f36e..857fe11 100644
--- a/app/source_graph/mapper.py
+++ b/app/source_graph/mapper.py
@@ -21,7 +21,7 @@ async def create_or_update_repos_from_source_graph_repos_data(
     """
     insert_statement = sqlalchemy.dialects.sqlite.insert(database.Repo)
     update_statement = insert_statement.on_conflict_do_update(
-        index_elements=[database.Repo.url],
+        index_elements=[database.Repo.url, database.Repo.source_graph_repo_id],
         set_={
             "url": insert_statement.excluded.url,
             "description": insert_statement.excluded.description,
diff --git a/db.sqlite3 b/db.sqlite3
index 9034064..cfe675e 100644
Binary files a/db.sqlite3 and b/db.sqlite3 differ
diff --git a/migrations/versions/0232d84a5aea_create_repo_dependency_and_.py b/migrations/versions/90eb9d1f9267_set_up_the_database.py
similarity index 52%
rename from migrations/versions/0232d84a5aea_create_repo_dependency_and_.py
rename to migrations/versions/90eb9d1f9267_set_up_the_database.py
index 8e8a4c1..03efee8 100644
--- a/migrations/versions/0232d84a5aea_create_repo_dependency_and_.py
+++ b/migrations/versions/90eb9d1f9267_set_up_the_database.py
@@ -1,15 +1,15 @@
-"""Create Repo, Dependency and RepoDependency tables
+"""Set up the database
 
-Revision ID: 0232d84a5aea
+Revision ID: 90eb9d1f9267
 Revises:
-Create Date: 2023-08-02 22:14:12.910175
+Create Date: 2023-08-15 14:13:30.562069
 
 """
 import sqlalchemy as sa
 from alembic import op
 
 # revision identifiers, used by Alembic.
-revision = "0232d84a5aea"
+revision = "90eb9d1f9267"
 down_revision = None
 branch_labels = None
 depends_on = None
@@ -21,8 +21,8 @@ def upgrade() -> None:
         "dependency",
         sa.Column("id", sa.Integer(), nullable=False),
         sa.Column("name", sa.String(length=255), nullable=False),
-        sa.PrimaryKeyConstraint("id"),
-        sa.UniqueConstraint("name"),
+        sa.PrimaryKeyConstraint("id", name=op.f("pk_dependency")),
+        sa.UniqueConstraint("name", name=op.f("uq_dependency_name ")),
     )
     op.create_table(
         "repo",
@@ -31,19 +31,36 @@ def upgrade() -> None:
         sa.Column("description", sa.Text(), nullable=False),
         sa.Column("stars", sa.BigInteger(), nullable=False),
         sa.Column("source_graph_repo_id", sa.BigInteger(), nullable=True),
-        sa.PrimaryKeyConstraint("id"),
-        sa.UniqueConstraint("source_graph_repo_id"),
-        sa.UniqueConstraint("url"),
+        sa.PrimaryKeyConstraint("id", name=op.f("pk_repo")),
+        sa.UniqueConstraint(
+            "source_graph_repo_id", name=op.f("uq_repo_source_graph_repo_id ")
+        ),
+        sa.UniqueConstraint(
+            "url",
+            "source_graph_repo_id",
+            name=op.f("uq_repo_url_source_graph_repo_id "),
+        ),
+        sa.UniqueConstraint("url", name=op.f("uq_repo_url ")),
     )
     op.create_table(
         "repo_dependency",
         sa.Column("repo_id", sa.Integer(), nullable=False),
         sa.Column("dependency_id", sa.Integer(), nullable=False),
         sa.ForeignKeyConstraint(
-            ["dependency_id"], ["dependency.id"], ondelete="CASCADE"
+            ["dependency_id"],
+            ["dependency.id"],
+            name=op.f("fk_repo_dependency_dependency_id_dependency"),
+            ondelete="CASCADE",
+        ),
+        sa.ForeignKeyConstraint(
+            ["repo_id"],
+            ["repo.id"],
+            name=op.f("fk_repo_dependency_repo_id_repo"),
+            ondelete="CASCADE",
+        ),
+        sa.PrimaryKeyConstraint(
+            "repo_id", "dependency_id", name=op.f("pk_repo_dependency")
         ),
-        sa.ForeignKeyConstraint(["repo_id"], ["repo.id"], ondelete="CASCADE"),
-        sa.PrimaryKeyConstraint("repo_id", "dependency_id"),
     )
     # ### end Alembic commands ###
 
diff --git a/pyproject.toml b/pyproject.toml
index 267295d..cc65b0d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,7 +16,7 @@ dependencies = [
     "alembic",
     "fastapi[all]",
     "httpx-sse",
-    "sqlalchemy[asyncio]",
+    "sqlalchemy[asyncio,mypy]",
     "stamina",
     "third-party-imports",
     "typer[all]",
@@ -114,7 +114,8 @@ convention = "numpy"
 
 [tool.mypy]
 plugins = [
-  "pydantic.mypy"
+  "pydantic.mypy",
+    "sqlalchemy.ext.mypy.plugin",
 ]
 strict = true
 exclude = [
diff --git a/requirements/base.txt b/requirements/base.txt
index 7487eb5..d4d113b 100644
--- a/requirements/base.txt
+++ b/requirements/base.txt
@@ -66,6 +66,10 @@ markupsafe==2.1.3
     #   mako
 mdurl==0.1.2
     # via markdown-it-py
+mypy==1.4.1
+    # via sqlalchemy
+mypy-extensions==1.0.0
+    # via mypy
 orjson==3.9.2
     # via fastapi
 pydantic==2.1.1
@@ -100,7 +104,7 @@ sniffio==1.3.0
     #   anyio
     #   httpcore
     #   httpx
-sqlalchemy[asyncio]==2.0.19
+sqlalchemy[asyncio,mypy]==2.0.19
     # via
     #   alembic
     #   awesome-fastapi-projects (pyproject.toml)
@@ -118,6 +122,7 @@ typing-extensions==4.7.1
     # via
     #   alembic
     #   fastapi
+    #   mypy
     #   pydantic
     #   pydantic-core
     #   sqlalchemy
diff --git a/requirements/dev.txt b/requirements/dev.txt
index d94e65a..67febb3 100644
--- a/requirements/dev.txt
+++ b/requirements/dev.txt
@@ -95,7 +95,9 @@ matplotlib-inline==0.1.6
 mdurl==0.1.2
     # via markdown-it-py
 mypy==1.4.1
-    # via awesome-fastapi-projects (pyproject.toml)
+    # via
+    #   awesome-fastapi-projects (pyproject.toml)
+    #   sqlalchemy
 mypy-extensions==1.0.0
     # via
     #   black
@@ -176,7 +178,7 @@ sniffio==1.3.0
     #   anyio
     #   httpcore
     #   httpx
-sqlalchemy[asyncio]==2.0.19
+sqlalchemy[asyncio,mypy]==2.0.19
     # via
     #   alembic
     #   awesome-fastapi-projects (pyproject.toml)
diff --git a/requirements/test.txt b/requirements/test.txt
index 4d1ce82..39dbb0f 100644
--- a/requirements/test.txt
+++ b/requirements/test.txt
@@ -75,6 +75,10 @@ markupsafe==2.1.3
     #   mako
 mdurl==0.1.2
     # via markdown-it-py
+mypy==1.4.1
+    # via sqlalchemy
+mypy-extensions==1.0.0
+    # via mypy
 orjson==3.9.2
     # via fastapi
 packaging==23.1
@@ -133,7 +137,7 @@ sniffio==1.3.0
     #   anyio
     #   httpcore
     #   httpx
-sqlalchemy[asyncio]==2.0.19
+sqlalchemy[asyncio,mypy]==2.0.19
     # via
     #   alembic
     #   awesome-fastapi-projects (pyproject.toml)
@@ -151,6 +155,7 @@ typing-extensions==4.7.1
     # via
     #   alembic
     #   fastapi
+    #   mypy
     #   polyfactory
     #   pydantic
     #   pydantic-core