Transaction API

Spanner read-write transaction support.

class google.cloud.spanner_v1.transaction.Transaction(session)

Implement read-write transaction semantics for a session.

• Parameters

  session( Session ) – the session used to perform the commit

• Raises

  ValueError – if session has an existing transaction

_ enter_ ()

Begin with block.

_ exit_ (exc_type, exc_val, exc_tb)

End with block.

batch_update(statements)

Perform a batch of DML statements via an ExecuteBatchDml request.

• Parameters

  statements( Sequence [ Union [ *[ str ]( https://python.readthedocs.io/en/latest/library/stdtypes.html#str ) , Tuple[ [ str ]( https://python.readthedocs.io/en/latest/library/stdtypes.html#str ) , Dict[ [ str ]( https://python.readthedocs.io/en/latest/library/stdtypes.html#str ) , Any] , **Dict[ [ str ]( https://python.readthedocs.io/en/latest/library/stdtypes.html#str ) , Union[ [ dict ]( https://python.readthedocs.io/en/latest/library/stdtypes.html#dict ) , [ types.Type ](spanner_v1/types.md#google.cloud.spanner_v1.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’.

• Return type

  Tuple(status, Sequence[ int ])

• Returns

  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 a transaction on the database.

• Return type

  bytes

• Returns

  the ID for the newly-begun transaction.

• Raises

  ValueError – if the transaction is already begun, committed, or rolled back.

commit(return_commit_stats=False)

Commit mutations to the database.

• Parameters

  return_commit_stats( bool ) – If true, the response will return commit stats which can be accessed though commit_stats.

• Return type

  datetime

• Returns

  timestamp of the committed changes.

• Raises

  ValueError – if there are no mutations to commit.

committed( = Non )

Timestamp at which the transaction was successfully committed.

delete(table, keyset)

Delete one or more table rows.

• Parameters

  • table( str ) – Name of the table to be modified.

  • keyset( Keyset ) – Keys/ranges identifying rows to delete.

execute_sql(sql, params=None, param_types=None, query_mode=None, query_options=None, partition=None, retry=<_MethodDefault._DEFAULT_VALUE:

Perform an ExecuteStreamingSql API request.

• Parameters

  • 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 ](spanner_v1/types.md#google.cloud.spanner_v1.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 .

  • query_options– (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

  • partition( bytes ) – (Optional) one of the partition tokens returned from partition_query() .

• Return type

  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.

execute_update(dml, params=None, param_types=None, query_mode=None, query_options=None)

Perform an ExecuteSql API request with DML.

• Parameters

  • 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 ](spanner_v1/types.md#google.cloud.spanner_v1.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 .

  • query_options( QueryOptions or dict ) – (Optional) Options that are provided for query plan stability.

• Return type

  int

• Returns

  Count of rows affected by the DML statement.

insert(table, columns, values)

Insert one or more new table rows.

• Parameters

  • 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(table, columns, values)

Insert/update one or more table rows.

• Parameters

  • 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(sql, params=None, param_types=None, partition_size_bytes=None, max_partitions=None)

Perform a ParitionQuery API request.

• Parameters

  • 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 ](spanner_v1/types.md#google.cloud.spanner_v1.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.

• Return type

  iterable of bytes

• Returns

  a sequence of partition tokens

• Raises

  ValueError – for single-use snapshots, or if a transaction ID is already associtated with the snapshot.

partition_read(table, columns, keyset, index='', partition_size_bytes=None, max_partitions=None)

Perform a ParitionRead API request for rows in a table.

• Parameters

  • 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.

• Return type

  iterable of bytes

• Returns

  a sequence of partition tokens

• Raises

  ValueError – for single-use snapshots, or if a transaction ID is already associtated with the snapshot.

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

Perform a StreamingRead API request for rows in a table.

• Parameters

  • 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 .

• Return type

  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.

replace(table, columns, values)

Replace one or more table rows.

• Parameters

  • 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()

Roll back a transaction on the database.

update(table, columns, values)

Update one or more existing table rows.

• Parameters

  • 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.