async def first(self, **kwargs: Any) -> "Model":
"""
Gets the first row from the db ordered by primary key column ascending.
:raises NoMatch: if no rows are returned
:raises MultipleMatches: if more than 1 row is returned.
:param kwargs: fields names and proper value types
:type kwargs: Any
:return: returned model
:rtype: Model
"""
if kwargs:
return await self.filter(**kwargs).first()
expr = self.build_select_expression(
limit=1,
order_bys=[
OrderAction(
order_str=f"{self.model.Meta.pkname}",
model_cls=self.model_cls, # type: ignore
)
] + self.order_bys,
)
rows = await self.database.fetch_all(expr)
processed_rows = self._process_query_result_rows(rows)
if self._prefetch_related and processed_rows:
processed_rows = await self._prefetch_related_models(
processed_rows, rows)
self.check_single_result_rows_count(processed_rows)
return processed_rows[0] # type: ignore
def order_by(self, columns: Union[List, str,
OrderAction]) -> "QuerySet[T]":
"""
With `order_by()` you can order the results from database based on your
choice of fields.
You can provide a string with field name or list of strings with fields names.
Ordering in sql will be applied in order of names you provide in order_by.
By default if you do not provide ordering `ormar` explicitly orders by
all primary keys
If you are sorting by nested models that causes that the result rows are
unsorted by the main model `ormar` will combine those children rows into
one main model.
The main model will never duplicate in the result
To order by main model field just provide a field name
To sort on nested models separate field names with dunder '__'.
You can sort this way across all relation types -> `ForeignKey`,
reverse virtual FK and `ManyToMany` fields.
To sort in descending order provide a hyphen in front of the field name
:param columns: columns by which models should be sorted
:type columns: Union[List, str]
:return: QuerySet
:rtype: QuerySet
"""
if not isinstance(columns, list):
columns = [columns]
orders_by = [
OrderAction(order_str=x, model_cls=self.model_cls) # type: ignore
if not isinstance(x, OrderAction) else x for x in columns
]
order_bys = self.order_bys + [
x for x in orders_by if x not in self.order_bys
]
return self.rebuild_self(order_bys=order_bys, )
async def get(self, *args: Any, **kwargs: Any) -> "T":
"""
Get's the first row from the db meeting the criteria set by kwargs.
If no criteria set it will return the last row in db sorted by pk.
Passing a criteria is actually calling filter(*args, **kwargs) method described
below.
:raises NoMatch: if no rows are returned
:raises MultipleMatches: if more than 1 row is returned.
:param kwargs: fields names and proper value types
:type kwargs: Any
:return: returned model
:rtype: Model
"""
if kwargs or args:
return await self.filter(*args, **kwargs).get()
if not self.filter_clauses:
expr = self.build_select_expression(
limit=1,
order_bys=[
OrderAction(
order_str=f"-{self.model.Meta.pkname}",
model_cls=self.model_cls, # type: ignore
)
] + self.order_bys,
)
else:
expr = self.build_select_expression()
rows = await self.database.fetch_all(expr)
processed_rows = self._process_query_result_rows(rows)
if self._prefetch_related and processed_rows:
processed_rows = await self._prefetch_related_models(
processed_rows, rows)
self.check_single_result_rows_count(processed_rows)
return processed_rows[0] # type: ignore