As of January 1, 2020 this library no longer supports Python 2 on the latest released version.
Library versions released prior to that date will continue to be available. For more information please
visit Python 2 support on Google Cloud.
Source code for google.cloud.spanner_v1.types.result_set
# -*- coding: utf-8 -*-
# Copyright 2020 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import proto # type: ignore
from google.cloud.spanner_v1.types import query_plan as gs_query_plan
from google.cloud.spanner_v1.types import transaction as gs_transaction
from google.cloud.spanner_v1.types import type as gs_type
from google.protobuf import struct_pb2 # type: ignore
__protobuf__ = proto.module(
package="google.spanner.v1",
manifest={"ResultSet", "PartialResultSet", "ResultSetMetadata", "ResultSetStats",},
)
[docs]class ResultSet(proto.Message):
r"""Results from [Read][google.spanner.v1.Spanner.Read] or
[ExecuteSql][google.spanner.v1.Spanner.ExecuteSql].
Attributes:
metadata (google.cloud.spanner_v1.types.ResultSetMetadata):
Metadata about the result set, such as row
type information.
rows (Sequence[google.protobuf.struct_pb2.ListValue]):
Each element in ``rows`` is a row whose format is defined by
[metadata.row_type][google.spanner.v1.ResultSetMetadata.row_type].
The ith element in each row matches the ith field in
[metadata.row_type][google.spanner.v1.ResultSetMetadata.row_type].
Elements are encoded based on type as described
[here][google.spanner.v1.TypeCode].
stats (google.cloud.spanner_v1.types.ResultSetStats):
Query plan and execution statistics for the SQL statement
that produced this result set. These can be requested by
setting
[ExecuteSqlRequest.query_mode][google.spanner.v1.ExecuteSqlRequest.query_mode].
DML statements always produce stats containing the number of
rows modified, unless executed using the
[ExecuteSqlRequest.QueryMode.PLAN][google.spanner.v1.ExecuteSqlRequest.QueryMode.PLAN]
[ExecuteSqlRequest.query_mode][google.spanner.v1.ExecuteSqlRequest.query_mode].
Other fields may or may not be populated, based on the
[ExecuteSqlRequest.query_mode][google.spanner.v1.ExecuteSqlRequest.query_mode].
"""
metadata = proto.Field(proto.MESSAGE, number=1, message="ResultSetMetadata",)
rows = proto.RepeatedField(proto.MESSAGE, number=2, message=struct_pb2.ListValue,)
stats = proto.Field(proto.MESSAGE, number=3, message="ResultSetStats",)
[docs]class PartialResultSet(proto.Message):
r"""Partial results from a streaming read or SQL query. Streaming
reads and SQL queries better tolerate large result sets, large
rows, and large values, but are a little trickier to consume.
Attributes:
metadata (google.cloud.spanner_v1.types.ResultSetMetadata):
Metadata about the result set, such as row
type information. Only present in the first
response.
values (Sequence[google.protobuf.struct_pb2.Value]):
A streamed result set consists of a stream of values, which
might be split into many ``PartialResultSet`` messages to
accommodate large rows and/or large values. Every N complete
values defines a row, where N is equal to the number of
entries in
[metadata.row_type.fields][google.spanner.v1.StructType.fields].
Most values are encoded based on type as described
[here][google.spanner.v1.TypeCode].
It is possible that the last value in values is "chunked",
meaning that the rest of the value is sent in subsequent
``PartialResultSet``\ (s). This is denoted by the
[chunked_value][google.spanner.v1.PartialResultSet.chunked_value]
field. Two or more chunked values can be merged to form a
complete value as follows:
- ``bool/number/null``: cannot be chunked
- ``string``: concatenate the strings
- ``list``: concatenate the lists. If the last element in a
list is a ``string``, ``list``, or ``object``, merge it
with the first element in the next list by applying these
rules recursively.
- ``object``: concatenate the (field name, field value)
pairs. If a field name is duplicated, then apply these
rules recursively to merge the field values.
Some examples of merging:
::
# Strings are concatenated.
"foo", "bar" => "foobar"
# Lists of non-strings are concatenated.
[2, 3], [4] => [2, 3, 4]
# Lists are concatenated, but the last and first elements are merged
# because they are strings.
["a", "b"], ["c", "d"] => ["a", "bc", "d"]
# Lists are concatenated, but the last and first elements are merged
# because they are lists. Recursively, the last and first elements
# of the inner lists are merged because they are strings.
["a", ["b", "c"]], [["d"], "e"] => ["a", ["b", "cd"], "e"]
# Non-overlapping object fields are combined.
{"a": "1"}, {"b": "2"} => {"a": "1", "b": 2"}
# Overlapping object fields are merged.
{"a": "1"}, {"a": "2"} => {"a": "12"}
# Examples of merging objects containing lists of strings.
{"a": ["1"]}, {"a": ["2"]} => {"a": ["12"]}
For a more complete example, suppose a streaming SQL query
is yielding a result set whose rows contain a single string
field. The following ``PartialResultSet``\ s might be
yielded:
::
{
"metadata": { ... }
"values": ["Hello", "W"]
"chunked_value": true
"resume_token": "Af65..."
}
{
"values": ["orl"]
"chunked_value": true
"resume_token": "Bqp2..."
}
{
"values": ["d"]
"resume_token": "Zx1B..."
}
This sequence of ``PartialResultSet``\ s encodes two rows,
one containing the field value ``"Hello"``, and a second
containing the field value ``"World" = "W" + "orl" + "d"``.
chunked_value (bool):
If true, then the final value in
[values][google.spanner.v1.PartialResultSet.values] is
chunked, and must be combined with more values from
subsequent ``PartialResultSet``\ s to obtain a complete
field value.
resume_token (bytes):
Streaming calls might be interrupted for a variety of
reasons, such as TCP connection loss. If this occurs, the
stream of results can be resumed by re-sending the original
request and including ``resume_token``. Note that executing
any other transaction in the same session invalidates the
token.
stats (google.cloud.spanner_v1.types.ResultSetStats):
Query plan and execution statistics for the statement that
produced this streaming result set. These can be requested
by setting
[ExecuteSqlRequest.query_mode][google.spanner.v1.ExecuteSqlRequest.query_mode]
and are sent only once with the last response in the stream.
This field will also be present in the last response for DML
statements.
"""
metadata = proto.Field(proto.MESSAGE, number=1, message="ResultSetMetadata",)
values = proto.RepeatedField(proto.MESSAGE, number=2, message=struct_pb2.Value,)
chunked_value = proto.Field(proto.BOOL, number=3,)
resume_token = proto.Field(proto.BYTES, number=4,)
stats = proto.Field(proto.MESSAGE, number=5, message="ResultSetStats",)
[docs]class ResultSetMetadata(proto.Message):
r"""Metadata about a [ResultSet][google.spanner.v1.ResultSet] or
[PartialResultSet][google.spanner.v1.PartialResultSet].
Attributes:
row_type (google.cloud.spanner_v1.types.StructType):
Indicates the field names and types for the rows in the
result set. For example, a SQL query like
``"SELECT UserId, UserName FROM Users"`` could return a
``row_type`` value like:
::
"fields": [
{ "name": "UserId", "type": { "code": "INT64" } },
{ "name": "UserName", "type": { "code": "STRING" } },
]
transaction (google.cloud.spanner_v1.types.Transaction):
If the read or SQL query began a transaction
as a side-effect, the information about the new
transaction is yielded here.
"""
row_type = proto.Field(proto.MESSAGE, number=1, message=gs_type.StructType,)
transaction = proto.Field(
proto.MESSAGE, number=2, message=gs_transaction.Transaction,
)
[docs]class ResultSetStats(proto.Message):
r"""Additional statistics about a
[ResultSet][google.spanner.v1.ResultSet] or
[PartialResultSet][google.spanner.v1.PartialResultSet].
This message has `oneof`_ fields (mutually exclusive fields).
For each oneof, at most one member field can be set at the same time.
Setting any member of the oneof automatically clears all other
members.
.. _oneof: https://proto-plus-python.readthedocs.io/en/stable/fields.html#oneofs-mutually-exclusive-fields
Attributes:
query_plan (google.cloud.spanner_v1.types.QueryPlan):
[QueryPlan][google.spanner.v1.QueryPlan] for the query
associated with this result.
query_stats (google.protobuf.struct_pb2.Struct):
Aggregated statistics from the execution of the query. Only
present when the query is profiled. For example, a query
could return the statistics as follows:
::
{
"rows_returned": "3",
"elapsed_time": "1.22 secs",
"cpu_time": "1.19 secs"
}
row_count_exact (int):
Standard DML returns an exact count of rows
that were modified.
This field is a member of `oneof`_ ``row_count``.
row_count_lower_bound (int):
Partitioned DML does not offer exactly-once
semantics, so it returns a lower bound of the
rows modified.
This field is a member of `oneof`_ ``row_count``.
"""
query_plan = proto.Field(proto.MESSAGE, number=1, message=gs_query_plan.QueryPlan,)
query_stats = proto.Field(proto.MESSAGE, number=2, message=struct_pb2.Struct,)
row_count_exact = proto.Field(proto.INT64, number=3, oneof="row_count",)
row_count_lower_bound = proto.Field(proto.INT64, number=4, oneof="row_count",)
__all__ = tuple(sorted(__protobuf__.manifest))