Class Transaction (1.14.0)

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)

Perform a batch of DML statements via an ExecuteBatchDml request.

Parameter

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'.

Returns
Type	Description
`Tuple(status, Sequence[int])`	Status code, plus counts of rows affected by each completed DML statement. Note that if the staus 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()

Commit mutations to the database.

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, partition=None, retry=<_MethodDefault._DEFAULT_VALUE: <object object>>, timeout=<_MethodDefault._DEFAULT_VALUE: <object object>>)

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 https://cloud.google.com/spanner/reference/rpc/google.spanner.v1#google.spanner.v1.ExecuteSqlRequest.QueryMode1
`partition`	`bytes` (Optional) one of the partition tokens returned from `partition_query`.

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)

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 https://cloud.google.com/spanner/reference/rpc/google.spanner.v1#google.spanner.v1.ExecuteSqlRequest.QueryMode1

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
)

Perform a ParitionQuery 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.

Exceptions
Type	Description
`ValueError`	for single-use snapshots, or if a transaction ID is already associtated 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
)

Perform a ParitionRead 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.

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

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

read

read(table, columns, keyset, index="", limit=0, partition=None)

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`.

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.