testcase stage2

db/dals.py

@@ -0,0 +1,47 @@
+from datetime import datetime
+
+from sqlalchemy import and_, desc, func, select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from db.models import Metrics, MetricsQuery, Query, Url
+
+###########################################################
+# BLOCK FOR INTERACTION WITH DATABASE IN BUSINESS CONTEXT #
+###########################################################
+
+
+class UrlDAL:
+    """Data Access Layer for operating user info"""
+
+    def __init__(self, db_session: AsyncSession):
+        self.db_session = db_session
+
+    async def add_new_urls(self, add_values: list[Url]):
+        for new_url in add_values:
+            query = select(Url).where(Url.url == new_url.url)
+            res = await self.db_session.execute(query)
+            if res.scalar_one_or_none() is None:
+                self.db_session.add(new_url)
+            else:
+                # If nessessary we can update data here
+                pass
+
+        await self.db_session.flush()
+        return
+
+
+class MetricDAL:
+    """Data Access Layer for operating user info"""
+
+    def __init__(self, db_session: AsyncSession):
+        self.db_session = db_session
+
+    async def get_last_metrics_date(self) -> datetime | None:
+        query = (
+            select(Metrics.date).group_by(Metrics.date).order_by(Metrics.date.desc())
+        )
+        result = await self.db_session.execute(query)
+        if result is None:
+            return None
+        last_date = result.scalars().first()
+        return last_date