Class Transaction (3.51.0)

Transaction(session)

Implement read-write transaction semantics for a session.

Parameter
Name	Description
`session`	`Session` the session used to perform the commit

Methods

enter

__enter__()

Begin with block.

exit

__exit__(exc_type, exc_val, exc_tb)

End with block.

batch_update

batch_update(
    statements,
    request_options=None,
    *,
    retry=_MethodDefault._DEFAULT_VALUE,
    timeout=_MethodDefault._DEFAULT_VALUE
)

Perform a batch of DML statements via an ExecuteBatchDml request.

Parameters
Name	Description
`statements`	`Sequence[Union[ str, Tuple[str, Dict[str, Any], Dict[str, Union[dict, .types.Type]]]]]` List of DML statements, with optional params / param types. If passed, 'params' is a dict mapping names to the values for parameter replacement. Keys must match the names used in the corresponding DML statement. If 'params' is passed, 'param_types' must also be passed, as a dict mapping names to the type of value passed in 'params'.
`request_options`	`RequestOptions` (Optional) Common options for this request. If a dict is provided, it must be of the same form as the protobuf message RequestOptions.
`retry`	`google.api_core.retry.Retry` (Optional) The retry settings for this request.
`timeout`	`float` (Optional) The timeout for this request.

Returns
Type	Description
`Tuple(status, Sequence[int])`	Status code, plus counts of rows affected by each completed DML statement. Note that if the status code is not `OK`, the statement triggering the error will not have an entry in the list, nor will any statements following that one.

begin

begin()

Begin a transaction on the database.

Exceptions
Type	Description
`ValueError`	if the transaction is already begun, committed, or rolled back.

Returns
Type	Description
`bytes`	the ID for the newly-begun transaction.

commit

commit(return_commit_stats=False, request_options=None, max_commit_delay=None)

Commit mutations to the database.

Parameters
Name	Description
`return_commit_stats`	`bool` If true, the response will return commit stats which can be accessed though commit_stats.
`request_options`	`RequestOptions` (Optional) Common options for this request. If a dict is provided, it must be of the same form as the protobuf message RequestOptions.
`max_commit_delay`	`datetime.timedelta` (Optional) The amount of latency this request is willing to incur in order to improve throughput. MaxCommitDelay.

Exceptions
Type	Description
`ValueError`	if there are no mutations to commit.

Returns
Type	Description
`datetime`	timestamp of the committed changes.

delete

delete(table, keyset)

Delete one or more table rows.

Parameters
Name	Description
`table`	`str` Name of the table to be modified.
`keyset`	`Keyset` Keys/ranges identifying rows to delete.

execute_sql

execute_sql(
    sql,
    params=None,
    param_types=None,
    query_mode=None,
    query_options=None,
    request_options=None,
    partition=None,
    retry=_MethodDefault._DEFAULT_VALUE,
    timeout=_MethodDefault._DEFAULT_VALUE,
    data_boost_enabled=False,
    directed_read_options=None,
    column_info=None,
    lazy_decode=False,
)

Perform an ExecuteStreamingSql API request.

Parameters
Name	Description
`sql`	`str` SQL query statement
`params`	`dict, {str -> column value}` values for parameter replacement. Keys must match the names used in `sql`.
`param_types`	`dict[str -> Union[dict, .types.Type]]` (Optional) maps explicit types for one or more param values; required if parameters are passed.
`query_mode`	`QueryMode` Mode governing return of results / query plan. See: `QueryMode https://cloud.google.com/spanner/reference/rpc/google.spanner.v1#google.spanner.v1.ExecuteSqlRequest.QueryMode`_.
`query_options`	`QueryOptions or dict` (Optional) Query optimizer configuration to use for the given query. If a dict is provided, it must be of the same form as the protobuf message QueryOptions
`request_options`	`RequestOptions` (Optional) Common options for this request. If a dict is provided, it must be of the same form as the protobuf message RequestOptions.
`partition`	`bytes` (Optional) one of the partition tokens returned from `partition_query`.
`retry`	`google.api_core.retry.Retry` (Optional) The retry settings for this request.
`timeout`	`float` (Optional) The timeout for this request.
`directed_read_options`	`DirectedReadOptions or dict` (Optional) Request level option used to set the directed_read_options for all ReadRequests and ExecuteSqlRequests that indicates which replicas or regions should be used for non-transactional reads or queries.
`column_info`	`dict` (Optional) dict of mapping between column names and additional column information. An object where column names as keys and custom objects as corresponding values for deserialization. It's specifically useful for data types like protobuf where deserialization logic is on user-specific code. When provided, the custom object enables deserialization of backend-received column data. If not provided, data remains serialized as bytes for Proto Messages and integer for Proto Enums.
`lazy_decode`	`bool` (Optional) If this argument is set to `true`, the iterator returns the underlying protobuf values instead of decoded Python objects. This reduces the time that is needed to iterate through large result sets. The application is responsible for decoding the data that is needed. The returned row iterator contains two functions that can be used for this. `iterator.decode_row(row)` decodes all the columns in the given row to an array of Python objects. `iterator.decode_column(row, column_index)` decodes one specific column in the given row.

Exceptions
Type	Description
`ValueError`	for reuse of single-use snapshots, or if a transaction ID is already pending for multiple-use snapshots.

Returns
Type	Description
`StreamedResultSet`	a result set instance which can be used to consume rows.

execute_update

execute_update(
    dml,
    params=None,
    param_types=None,
    query_mode=None,
    query_options=None,
    request_options=None,
    *,
    retry=_MethodDefault._DEFAULT_VALUE,
    timeout=_MethodDefault._DEFAULT_VALUE
)

Perform an ExecuteSql API request with DML.

Parameters
Name	Description
`dml`	`str` SQL DML statement
`params`	`dict, {str -> column value}` values for parameter replacement. Keys must match the names used in `dml`.
`param_types`	`dict[str -> Union[dict, .types.Type]]` (Optional) maps explicit types for one or more param values; required if parameters are passed.
`query_mode`	`QueryMode` Mode governing return of results / query plan. See: `QueryMode https://cloud.google.com/spanner/reference/rpc/google.spanner.v1#google.spanner.v1.ExecuteSqlRequest.QueryMode`_.
`query_options`	`QueryOptions or dict` (Optional) Options that are provided for query plan stability.
`request_options`	`RequestOptions` (Optional) Common options for this request. If a dict is provided, it must be of the same form as the protobuf message RequestOptions.
`retry`	`google.api_core.retry.Retry` (Optional) The retry settings for this request.
`timeout`	`float` (Optional) The timeout for this request.

Returns
Type	Description
`int`	Count of rows affected by the DML statement.

insert

insert(table, columns, values)

Insert one or more new table rows.

Parameters
Name	Description
`table`	`str` Name of the table to be modified.
`columns`	`list of str` Name of the table columns to be modified.
`values`	`list of lists` Values to be modified.

insert_or_update

insert_or_update(table, columns, values)

Insert/update one or more table rows.

Parameters
Name	Description
`table`	`str` Name of the table to be modified.
`columns`	`list of str` Name of the table columns to be modified.
`values`	`list of lists` Values to be modified.

partition_query

partition_query(
    sql,
    params=None,
    param_types=None,
    partition_size_bytes=None,
    max_partitions=None,
    *,
    retry=_MethodDefault._DEFAULT_VALUE,
    timeout=_MethodDefault._DEFAULT_VALUE
)

Perform a PartitionQuery API request.

Parameters
Name	Description
`sql`	`str` SQL query statement
`params`	`dict, {str -> column value}` values for parameter replacement. Keys must match the names used in `sql`.
`param_types`	`dict[str -> Union[dict, .types.Type]]` (Optional) maps explicit types for one or more param values; required if parameters are passed.
`partition_size_bytes`	`int` (Optional) desired size for each partition generated. The service uses this as a hint, the actual partition size may differ.
`max_partitions`	`int` (Optional) desired maximum number of partitions generated. The service uses this as a hint, the actual number of partitions may differ.
`retry`	`google.api_core.retry.Retry` (Optional) The retry settings for this request.
`timeout`	`float` (Optional) The timeout for this request.

Exceptions
Type	Description
`ValueError`	for single-use snapshots, or if a transaction ID is already associated with the snapshot.

Returns
Type	Description
`iterable of bytes`	a sequence of partition tokens

partition_read

partition_read(
    table,
    columns,
    keyset,
    index="",
    partition_size_bytes=None,
    max_partitions=None,
    *,
    retry=_MethodDefault._DEFAULT_VALUE,
    timeout=_MethodDefault._DEFAULT_VALUE
)

Perform a PartitionRead API request for rows in a table.

Parameters
Name	Description
`table`	`str` name of the table from which to fetch data
`columns`	`list of str` names of columns to be retrieved
`keyset`	`KeySet` keys / ranges identifying rows to be retrieved
`index`	`str` (Optional) name of index to use, rather than the table's primary key
`partition_size_bytes`	`int` (Optional) desired size for each partition generated. The service uses this as a hint, the actual partition size may differ.
`max_partitions`	`int` (Optional) desired maximum number of partitions generated. The service uses this as a hint, the actual number of partitions may differ.
`retry`	`google.api_core.retry.Retry` (Optional) The retry settings for this request.
`timeout`	`float` (Optional) The timeout for this request.

Exceptions
Type	Description
`ValueError`	for single-use snapshots, or if a transaction ID is already associated with the snapshot.

Returns
Type	Description
`iterable of bytes`	a sequence of partition tokens

read

read(
    table,
    columns,
    keyset,
    index="",
    limit=0,
    partition=None,
    request_options=None,
    data_boost_enabled=False,
    directed_read_options=None,
    *,
    retry=_MethodDefault._DEFAULT_VALUE,
    timeout=_MethodDefault._DEFAULT_VALUE,
    column_info=None,
    lazy_decode=False
)

Perform a StreamingRead API request for rows in a table.

Parameters
Name	Description
`table`	`str` name of the table from which to fetch data
`columns`	`list of str` names of columns to be retrieved
`keyset`	`KeySet` keys / ranges identifying rows to be retrieved
`index`	`str` (Optional) name of index to use, rather than the table's primary key
`limit`	`int` (Optional) maximum number of rows to return. Incompatible with `partition`.
`partition`	`bytes` (Optional) one of the partition tokens returned from `partition_read`. Incompatible with `limit`.
`request_options`	`RequestOptions` (Optional) Common options for this request. If a dict is provided, it must be of the same form as the protobuf message RequestOptions. Please note, the `transactionTag` setting will be ignored for snapshot as it's not supported for read-only transactions.
`retry`	`google.api_core.retry.Retry` (Optional) The retry settings for this request.
`timeout`	`float` (Optional) The timeout for this request.
`directed_read_options`	`DirectedReadOptions or dict` (Optional) Request level option used to set the directed_read_options for all ReadRequests and ExecuteSqlRequests that indicates which replicas or regions should be used for non-transactional reads or queries.
`column_info`	`dict` (Optional) dict of mapping between column names and additional column information. An object where column names as keys and custom objects as corresponding values for deserialization. It's specifically useful for data types like protobuf where deserialization logic is on user-specific code. When provided, the custom object enables deserialization of backend-received column data. If not provided, data remains serialized as bytes for Proto Messages and integer for Proto Enums.
`lazy_decode`	`bool` (Optional) If this argument is set to `true`, the iterator returns the underlying protobuf values instead of decoded Python objects. This reduces the time that is needed to iterate through large result sets. The application is responsible for decoding the data that is needed. The returned row iterator contains two functions that can be used for this. `iterator.decode_row(row)` decodes all the columns in the given row to an array of Python objects. `iterator.decode_column(row, column_index)` decodes one specific column in the given row.

Exceptions
Type	Description
`ValueError`	for reuse of single-use snapshots, or if a transaction ID is already pending for multiple-use snapshots.

Returns
Type	Description
`StreamedResultSet`	a result set instance which can be used to consume rows.

replace

replace(table, columns, values)

Replace one or more table rows.

Parameters
Name	Description
`table`	`str` Name of the table to be modified.
`columns`	`list of str` Name of the table columns to be modified.
`values`	`list of lists` Values to be modified.

rollback

rollback()

Roll back a transaction on the database.

update

update(table, columns, values)

Update one or more existing table rows.

Parameters
Name	Description
`table`	`str` Name of the table to be modified.
`columns`	`list of str` Name of the table columns to be modified.
`values`	`list of lists` Values to be modified.