Python Session.count方法代码示例

# 需要导入模块: from pyramid_sqlalchemy import Session [as 别名]
# 或者: from pyramid_sqlalchemy.Session import count [as 别名]
    def get_collection(cls, **params):
        """ Query collection and return results.

        Notes:
        *   Before validating that only model fields are present in params,
            reserved params, query params and all params starting with
            double underscore are dropped.
        *   Params which have value "_all" are dropped.
        *   When ``_count`` param is used, objects count is returned
            before applying offset and limit.

        :param bool __strict: If True ``params`` are validated to contain
            only fields defined on model, exception is raised if invalid
            fields are present. When False - invalid fields are dropped.
            Defaults to ``True``.
        :param bool _item_request: Indicates whether it is a single item
            request or not. When True and DataError happens on DB request,
            JHTTPNotFound is raised. JHTTPBadRequest is raised when False.
            Defaults to ``False``.
        :param list _sort: Field names to sort results by. If field name
            is prefixed with "-" it is used for "descending" sorting.
            Otherwise "ascending" sorting is performed by that field.
            Defaults to an empty list in which case sorting is not
            performed.
        :param list _fields: Names of fields which should be included
            or excluded from results. Fields to excluded should be
            prefixed with "-". Defaults to an empty list in which
            case all fields are returned.
        :param int _limit: Number of results per page. Defaults
            to None in which case all results are returned.
        :param int _page: Number of page. In conjunction with
            ``_limit`` is used to calculate results offset. Defaults to
            None in which case it is ignored. Params ``_page`` and
            ``_start` are mutually exclusive.
        :param int _start: Results offset. If provided ``_limit`` and
            ``_page`` params are ignored when calculating offset. Defaults
            to None. Params ``_page`` and ``_start`` are mutually
            exclusive. If not offset-related params are provided, offset
            equals to 0.
        :param Query query_set: Existing queryset. If provided, all queries
            are applied to it instead of creating new queryset. Defaults
            to None.
        :param _count: When provided, only results number is returned as
            integer.
        :param _explain: When provided, query performed(SQL) is returned
            as a string instead of query results.
        :param bool __raise_on_empty: When True JHTTPNotFound is raised
            if query returned no results. Defaults to False in which case
            error is just logged and empty query results are returned.

        :returns: Query results as ``sqlalchemy.orm.query.Query`` instance.
            May be sorted, offset, limited.
        :returns: Dict of {'field_name': fieldval}, when ``_fields`` param
            is provided.
        :returns: Number of query results as an int when ``_count`` param
            is provided.
        :returns: String representing query ran when ``_explain`` param
            is provided.

        :raises JHTTPNotFound: When ``__raise_on_empty=True`` and no
            results found.
        :raises JHTTPNotFound: When ``_item_request=True`` and
            ``sqlalchemy.exc.DataError`` exception is raised during DB
            query. Latter exception is raised when querying DB with
            an identifier of a wrong type. E.g. when querying Int field
            with a string.
        :raises JHTTPBadRequest: When ``_item_request=False`` and
            ``sqlalchemy.exc.DataError`` exception is raised during DB
            query.
        :raises JHTTPBadRequest: When ``sqlalchemy.exc.InvalidRequestError``
            or ``sqlalchemy.exc.IntegrityError`` errors happen during DB
            query.
        """
        log.debug('Get collection: {}, {}'.format(cls.__name__, params))
        params.pop('__confirmation', False)
        __strict = params.pop('__strict', True)
        _item_request = params.pop('_item_request', False)

        _sort = _split(params.pop('_sort', []))
        _fields = _split(params.pop('_fields', []))
        _limit = params.pop('_limit', None)
        _page = params.pop('_page', None)
        _start = params.pop('_start', None)
        query_set = params.pop('query_set', None)

        _count = '_count' in params
        params.pop('_count', None)
        _explain = '_explain' in params
        params.pop('_explain', None)
        __raise_on_empty = params.pop('__raise_on_empty', False)

        if query_set is None:
            query_set = Session().query(cls)

        # Remove any __ legacy instructions from this point on
        params = dictset({
            key: val for key, val in params.items()
            if not key.startswith('__')
        })

#.........这里部分代码省略.........