def execute_sql(self, sql, params=None, param_types=None, query_mode=None,
resume_token=b''):
"""Perform an ``ExecuteStreamingSql`` API request for rows in a table.
:type sql: str
:param sql: SQL query statement
:type params: dict, {str -> column value}
:param params: values for parameter replacement. Keys must match
the names used in ``sql``.
:type param_types: dict
:param param_types:
(Optional) maps explicit types for one or more param values;
required if parameters are passed.
:type query_mode:
:class:`google.cloud.proto.spanner.v1.ExecuteSqlRequest.QueryMode`
:param query_mode: Mode governing return of results / query plan. See
https://cloud.google.com/spanner/reference/rpc/google.spanner.v1#google.spanner.v1.ExecuteSqlRequest.QueryMode1
:type resume_token: bytes
:param resume_token: token for resuming previously-interrupted query
:rtype: :class:`~google.cloud.spanner.streamed.StreamedResultSet`
:returns: a result set instance which can be used to consume rows.
:raises ValueError:
for reuse of single-use snapshots, or if a transaction ID is
already pending for multiple-use snapshots.
"""
if self._read_request_count > 0:
if not self._multi_use:
raise ValueError("Cannot re-use single-use snapshot.")
if self._transaction_id is None:
raise ValueError("Transaction ID pending.")
if params is not None:
if param_types is None:
raise ValueError(
"Specify 'param_types' when passing 'params'.")
params_pb = Struct(fields={
key: _make_value_pb(value) for key, value in params.items()})
else:
params_pb = None
database = self._session._database
options = _options_with_prefix(database.name)
transaction = self._make_txn_selector()
api = database.spanner_api
iterator = api.execute_streaming_sql(
self._session.name, sql,
transaction=transaction, params=params_pb, param_types=param_types,
query_mode=query_mode, resume_token=resume_token, options=options)
self._read_request_count += 1
if self._multi_use:
return StreamedResultSet(iterator, source=self)
else:
return StreamedResultSet(iterator)
def read(self, table, columns, keyset, index='', limit=0):
"""Perform a ``StreamingRead`` API request for rows in a table.
:type table: str
:param table: name of the table from which to fetch data
:type columns: list of str
:param columns: names of columns to be retrieved
:type keyset: :class:`~google.cloud.spanner.keyset.KeySet`
:param keyset: keys / ranges identifying rows to be retrieved
:type index: str
:param index: (Optional) name of index to use, rather than the
table's primary key
:type limit: int
:param limit: (Optional) maxiumn number of rows to return
:rtype: :class:`~google.cloud.spanner.streamed.StreamedResultSet`
:returns: a result set instance which can be used to consume rows.
:raises ValueError:
for reuse of single-use snapshots, or if a transaction ID is
already pending for multiple-use snapshots.
"""
if self._read_request_count > 0:
if not self._multi_use:
raise ValueError("Cannot re-use single-use snapshot.")
if self._transaction_id is None:
raise ValueError("Transaction ID pending.")
database = self._session._database
api = database.spanner_api
options = _options_with_prefix(database.name)
transaction = self._make_txn_selector()
restart = functools.partial(api.streaming_read,
self._session.name,
table,
columns,
keyset.to_pb(),
transaction=transaction,
index=index,
limit=limit,
options=options)
iterator = _restart_on_unavailable(restart)
self._read_request_count += 1
if self._multi_use:
return StreamedResultSet(iterator, source=self)
else:
return StreamedResultSet(iterator)
def read(self,
table,
columns,
keyset,
index='',
limit=0,
resume_token=b''):
"""Perform a ``StreamingRead`` API request for rows in a table.
:type table: str
:param table: name of the table from which to fetch data
:type columns: list of str
:param columns: names of columns to be retrieved
:type keyset: :class:`~google.cloud.spanner.keyset.KeySet`
:param keyset: keys / ranges identifying rows to be retrieved
:type index: str
:param index: (Optional) name of index to use, rather than the
table's primary key
:type limit: int
:param limit: (Optional) maxiumn number of rows to return
:type resume_token: bytes
:param resume_token: token for resuming previously-interrupted read
:rtype: :class:`~google.cloud.spanner.streamed.StreamedResultSet`
:returns: a result set instance which can be used to consume rows.
"""
database = self._session._database
api = database.spanner_api
options = _options_with_prefix(database.name)
transaction = self._make_txn_selector()
iterator = api.streaming_read(self._session.name,
table,
columns,
keyset.to_pb(),
transaction=transaction,
index=index,
limit=limit,
resume_token=resume_token,
options=options)
return StreamedResultSet(iterator)