fix curriculum membership (#813)

### Description

Please explain the changes you made here.

### Checklist

- [ ] Created tests which fail without the change (if possible)
- [ ] All tests passing
- [ ] Extended the documentation, if necessary

Author: Malem38

app/modules/cdr/cruds_cdr.py

@@ -174,9 +174,11 @@ async def get_product_by_id(
     product_id: UUID,
 ) -> models_cdr.CdrProduct | None:
     result = await db.execute(
-        select(models_cdr.CdrProduct).where(
+        select(models_cdr.CdrProduct)
+        .where(
             models_cdr.CdrProduct.id == product_id,
-        ),
+        )
+        .options(selectinload(models_cdr.CdrProduct.product_constraints)),
     )
     return result.unique().scalars().first()
 

app/modules/cdr/models_cdr.py

@@ -135,7 +135,6 @@ class CurriculumMembership(Base):
     )
     curriculum_id: Mapped[uuid.UUID] = mapped_column(
         ForeignKey("cdr_curriculum.id"),
-        primary_key=True,
     )
 
 

migrations/versions/39_remove_curriculum_memberships_duplicate.py

@@ -0,0 +1,71 @@
+"""remove curriculum memberships duplicate
+
+Create Date: 2025-09-01 11:47:32.727885
+"""
+
+from collections.abc import Sequence
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from pytest_alembic import MigrationContext
+
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = "2880c583d7f1"
+down_revision: str | None = "06c94803745b"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade():
+    op.drop_constraint(
+        "cdr_curriculum_membership_pkey",
+        table_name="cdr_curriculum_membership",
+        type_="primary",
+    )
+
+    op.execute("""
+        DELETE FROM cdr_curriculum_membership AS c
+        WHERE EXISTS (
+            SELECT 1
+            FROM cdr_curriculum_membership AS sub
+            WHERE sub.user_id = c.user_id
+            AND sub.curriculum_id < c.curriculum_id
+    );
+    """)
+
+    op.create_primary_key(
+        "cdr_curriculum_membership_pkey",
+        "cdr_curriculum_membership",
+        ["user_id"],
+    )
+
+
+def downgrade():
+    op.drop_constraint(
+        "cdr_curriculum_membership_pkey",
+        table_name="cdr_curriculum_membership",
+        type_="primary",
+    )
+
+    op.create_primary_key(
+        "cdr_curriculum_membership_pkey",
+        "cdr_curriculum_membership",
+        ["user_id", "curriculum_id"],
+    )
+
+
+def pre_test_upgrade(
+    alembic_runner: "MigrationContext",
+    alembic_connection: sa.Connection,
+) -> None:
+    pass
+
+
+def test_upgrade(
+    alembic_runner: "MigrationContext",
+    alembic_connection: sa.Connection,
+) -> None:
+    pass