Implemented alembic migrations, added cursors closing task.

data/schemas.py

@@ -124,8 +124,8 @@ class SelectQueryBase(BaseModel):
     columns: Union[Literal["*"], List[str]] = "*"
     filters: Optional[List[FilterClause]] = None
     sort_by: Optional[List[SortClause]] = None
-    limit: Annotated[int, Field(strict=True, gt=0)] = None
-    offset: Annotated[int, Field(strict=True, ge=0)] = None
+    limit: Optional[Annotated[int, Field(strict=True, gt=0)]] = None
+    offset: Optional[Annotated[int, Field(strict=True, ge=0)]] = None
 
     @field_validator("table_name")
     @classmethod
@@ -179,16 +179,20 @@ class SelectQueryInResult(BaseModel):
         from_attributes = True
 
 
-class SelectQueryMetaData(BaseModel):
-    cursor: Optional[UUID4] = Field(
-        None,
-        description="A UUID4 cursor for pagination. Can be None if no more data is available.",
-    )
-    total_number: int
-    has_more: bool = False
+class CachedCursorOut(BaseModel):
+    id: UUID4 | None
+    connection_id: int
+    query: SelectQueryInResult
+    row_count: int
+    fetched_rows: int
+    is_closed: bool
+    has_more: bool
+    close_at: int
+    ttl: int
+    class Config:
+        from_attributes = True
 
 
 class SelectResult(BaseModel):
-    meta: SelectQueryMetaData
-    query: SelectQueryInResult
+    cursor: CachedCursorOut
     results: SelectResultData | None