Python client library  |  Google Cloud (original) (raw)

Database API

User friendly container for Cloud Spanner Database.

class google.cloud.spanner_v1.database.BatchCheckout(database, request_options=None)

Bases: object

Context manager for using a batch from a database.

Inside the context manager, checks out a session from the database, creates a batch from it, making the batch available.

Caller must not use the batch to perform API requests outside the scope of the context manager.

• Parameters
  • database (Database) – database to use
  • request_options (google.cloud.spanner_v1.types.RequestOptions) – (Optional) Common options for the commit request. If a dict is provided, it must be of the same form as the protobuf message RequestOptions.

_ enter_()

Begin with block.

_ exit_(exc_type, exc_val, exc_tb)

End with block.

class google.cloud.spanner_v1.database.BatchSnapshot(database, read_timestamp=None, exact_staleness=None)

Bases: object

Wrapper for generating and processing read / query batches.

• Parameters
  • database (Database) – database to use
  • read_timestamp (datetime.datetime) – Execute all reads at the given timestamp.
  • exact_staleness (datetime.timedelta) – Execute all reads at a timestamp that isexact_staleness old.

close()

Clean up underlying session.

NOTE: If the transaction has been shared across multiple machines, calling this on any machine would invalidate the transaction everywhere. Ideally this would be called when data has been read from all the partitions.

execute_sql(*args, **kw)

Convenience method: perform query operation via snapshot.

See execute_sql().

classmethod from_dict(database, mapping)

Reconstruct an instance from a mapping.

• Parameters
  • database (Database) – database to use
  • mapping (mapping) – serialized state of the instance
• Return type
  BatchSnapshot

generate_query_batches(sql, params=None, param_types=None, partition_size_bytes=None, max_partitions=None, query_options=None, data_boost_enabled=False, *, retry=<_MethodDefault._DEFAULT_VALUE:

Start a partitioned query operation.

Uses the PartitionQuery API request to start a partitioned query operation. Returns a list of batch information needed to perform the actual queries.

• 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.
  • partition_size_bytes – (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.
  • query_options (QueryOptionsor 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
  • data_boost_enabled – (Optional) If this is for a partitioned query and this field is set true, the request will be executed via offline access.
  • retry (Retry) – (Optional) The retry settings for this request.
  • timeout (float) – (Optional) The timeout for this request.
• Return type
  iterable of dict
• Returns
  mappings of information used perform actual partitioned reads viaprocess_read_batch().

generate_read_batches(table, columns, keyset, index='', partition_size_bytes=None, max_partitions=None, data_boost_enabled=False, *, retry=<_MethodDefault._DEFAULT_VALUE:

Start a partitioned batch read operation.

Uses the PartitionRead API request to initiate the partitioned read. Returns a list of batch information needed to perform the actual reads.

• 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.
  • data_boost_enabled – (Optional) If this is for a partitioned read and this field is set true, the request will be executed via offline access.
  • retry (Retry) – (Optional) The retry settings for this request.
  • timeout (float) – (Optional) The timeout for this request.
• Return type
  iterable of dict
• Returns
  mappings of information used perform actual partitioned reads viaprocess_read_batch().

process(batch)

Process a single, partitioned query or read.

• Parameters
  batch (mapping) – one of the mappings returned from an earlier call togenerate_query_batches().
• Return type
  StreamedResultSet
• Returns
  a result set instance which can be used to consume rows.
• Raises
  ValueError – if batch does not contain either ‘read’ or ‘query’

process_query_batch(batch, *, retry=<_MethodDefault._DEFAULT_VALUE:

Process a single, partitioned query.

• Parameters
  • batch (mapping) – one of the mappings returned from an earlier call togenerate_query_batches().
  • retry (Retry) – (Optional) The retry settings for this request.
  • timeout (float) – (Optional) The timeout for this request.
• Return type
  StreamedResultSet
• Returns
  a result set instance which can be used to consume rows.

process_read_batch(batch, *, retry=<_MethodDefault._DEFAULT_VALUE:

Process a single, partitioned read.

• Parameters
  • batch (mapping) – one of the mappings returned from an earlier call togenerate_read_batches().
  • retry (Retry) – (Optional) The retry settings for this request.
  • timeout (float) – (Optional) The timeout for this request.
• Return type
  StreamedResultSet
• Returns
  a result set instance which can be used to consume rows.

read(*args, **kw)

Convenience method: perform read operation via snapshot.

See read().

to_dict()

Return state as a dictionary.

Result can be used to serialize the instance and reconstitute it later using from_dict().

• Return type
  dict

class google.cloud.spanner_v1.database.Database(database_id, instance, ddl_statements=(), pool=None, logger=None, encryption_config=None, database_dialect=<DatabaseDialect.DATABASE_DIALECT_UNSPECIFIED: 0>, database_role=None, enable_drop_protection=False)

Bases: object

Representation of a Cloud Spanner Database.

We can use a Database to:

• create() the database
• reload() the database
• update() the database
• drop() the database
• Parameters
  • database_id (str) – The ID of the database.
  • instance (Instance) – The instance that owns the database.
  • ddl_statements (list of string) – (Optional) DDL statements, excluding the CREATE DATABASE statement.
  • pool (concrete subclass ofAbstractSessionPool.) – (Optional) session pool to be used by database. If not passed, the database will construct an instance ofBurstyPool.
  • logger (logging.Logger) – (Optional) a custom logger that is used if log_commit_stats is True to log commit statistics. If not passed, a logger will be created when needed that will log the commit statistics to stdout.
  • encryption_config (EncryptionConfigor RestoreDatabaseEncryptionConfigor dict) – (Optional) Encryption configuration for the database. If a dict is provided, it must be of the same form as either of the protobuf messages EncryptionConfigor RestoreDatabaseEncryptionConfig
  • database_dialect (DatabaseDialect) – (Optional) database dialect for the database
  • database_role (str* or _[_None*](https://python.readthedocs.io/en/latest/library/constants.html#None)) – (Optional) user-assigned database_role for the session.
  • enable_drop_protection (boolean) – (Optional) Represents whether the database has drop protection enabled or not.

batch(request_options=None)

Return an object which wraps a batch.

The wrapper must be used as a context manager, with the batch as the value returned by the wrapper.

• Parameters
  request_options (google.cloud.spanner_v1.types.RequestOptions) – (Optional) Common options for the commit request. If a dict is provided, it must be of the same form as the protobuf message RequestOptions.
• Return type
  BatchCheckout
• Returns
  new wrapper

batch_snapshot(read_timestamp=None, exact_staleness=None)

Return an object which wraps a batch read / query.

• Parameters
  • read_timestamp (datetime.datetime) – Execute all reads at the given timestamp.
  • exact_staleness (datetime.timedelta) – Execute all reads at a timestamp that isexact_staleness old.
• Return type
  BatchSnapshot
• Returns
  new wrapper

create()

Create this database within its instance

Includes any configured schema assigned to ddl_statements.

Seehttps://cloud.google.com/spanner/reference/rpc/google.spanner.admin.database.v1#google.spanner.admin.database.v1.DatabaseAdmin.CreateDatabase

• Return type
  Operation
• Returns
  a future used to poll the status of the create request
• Raises
  • Conflict – if the database already exists
  • NotFound – if the instance owning the database does not exist

property create_time()

Create time of this database.

• Return type
  datetime.datetime
• Returns
  a datetime object representing the create time of this database

property database_dialect()

DDL Statements used to define database schema.

See cloud.google.com/spanner/docs/data-definition-language

• Return type
  google.cloud.spanner_admin_database_v1.types.DatabaseDialect
• Returns
  the dialect of the database

property database_role()

User-assigned database_role for sessions created by the pool. :rtype: str :returns: a str with the name of the database role.

property ddl_statements()

DDL Statements used to define database schema.

See cloud.google.com/spanner/docs/data-definition-language

• Return type
  sequence of string
• Returns
  the statements

property default_leader()

The read-write region which contains the database’s leader replicas.

• Return type
  str
• Returns
  a string representing the read-write region

drop()

Drop this database.

Seehttps://cloud.google.com/spanner/reference/rpc/google.spanner.admin.database.v1#google.spanner.admin.database.v1.DatabaseAdmin.DropDatabase

property earliest_version_time()

The earliest time at which older versions of the data can be read.

• Return type
  datetime.datetime
• Returns
  a datetime object representing the earliest version time

property enable_drop_protection()

Whether the database has drop protection enabled.

• Return type
  boolean
• Returns
  a boolean representing whether the database has drop protection enabled

property encryption_config()

Encryption config for this database. :rtype: EncryptionConfig:returns: an object representing the encryption config for this database

property encryption_info()

Encryption info for this database. :rtype: a list of EncryptionInfo:returns: a list of objects representing encryption info for this database

execute_partitioned_dml(dml, params=None, param_types=None, query_options=None, request_options=None)

Execute a partitionable DML statement.

• Parameters
  • dml (str) – 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_options (QueryOptionsor 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 (google.cloud.spanner_v1.types.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 as it is not supported for partitioned DML.
• Return type
  int
• Returns
  Count of rows affected by the DML statement.

exists()

Test whether this database exists.

Seehttps://cloud.google.com/spanner/reference/rpc/google.spanner.admin.database.v1#google.spanner.admin.database.v1.DatabaseAdmin.GetDatabaseDDL

• Return type
  bool
• Returns
  True if the database exists, else false.

classmethod from_pb(database_pb, instance, pool=None)

Creates an instance of this class from a protobuf.

• Parameters
  • database_pb (Instance) – A instance protobuf object.
  • instance (Instance) – The instance that owns the database.
  • pool (concrete subclass ofAbstractSessionPool.) – (Optional) session pool to be used by database.
• Return type
  Database
• Returns
  The database parsed from the protobuf response.
• Raises
  ValueError – if the instance name does not match the expected format or if the parsed project ID does not match the project ID on the instance’s client, or if the parsed instance ID does not match the instance’s ID.

get_iam_policy(policy_version=None)

Gets the access control policy for a database resource.

• Parameters
  policy_version (int) – (Optional) the maximum policy version that will be used to format the policy. Valid values are 0, 1 ,3.
• Return type
  Policy
• Returns
  returns an Identity and Access Management (IAM) policy. It is used to specify access control policies for Cloud Platform resources.

is_optimized()

Test whether this database has finished optimizing.

• Return type
  bool
• Returns
  True if the database state is READY, else False.

is_ready()

Test whether this database is ready for use.

• Return type
  bool
• Returns
  True if the database state is READY_OPTIMIZING or READY, else False.

list_database_operations(filter_='', page_size=None)

List database operations for the database.

• Parameters
  • filter (str) – Optional. A string specifying a filter for which database operations to list.
  • page_size (int) – Optional. The maximum number of operations in each page of results from this request. Non-positive values are ignored. Defaults to a sensible value set by the API.
• Type
  Iterator
• Returns
  Iterator of Operation resources within the current instance.

list_database_roles(page_size=None)

Lists Cloud Spanner database roles.

• Parameters
  page_size (int) – Optional. The maximum number of database roles in each page of results from this request. Non-positive values are ignored. Defaults to a sensible value set by the API.
• Type
  Iterable
• Returns
  Iterable of DatabaseRole resources within the current database.

list_tables()

List tables within the database.

• Type
  Iterable
• Returns
  Iterable of Table resources within the current database.

property logger()

Logger used by the database.

The default logger will log commit stats at the log level INFO using sys.stderr.

• Return type
  logging.Logger or None
• Returns
  the logger

property name()

Database name used in requests.

NOTE: This property will not change if database_id does not, but the return value is not cached.

The database name is of the form

"projects/../instances/../databases/{database_id}"

• Return type
  str
• Returns
  The database name.

property reconciling()

Whether the database is currently reconciling.

• Return type
  boolean
• Returns
  a boolean representing whether the database is reconciling

reload()

Reload this database.

Refresh any configured schema into ddl_statements.

Seehttps://cloud.google.com/spanner/reference/rpc/google.spanner.admin.database.v1#google.spanner.admin.database.v1.DatabaseAdmin.GetDatabaseDDL

• Raises
  NotFound – if the database does not exist

restore(source)

Restore from a backup to this database.

• Parameters
  source (Backup) – the path of the source being restored from.
• Return type
  Operation
• Returns
  a future used to poll the status of the create request
• Raises
  • Conflict – if the database already exists
  • NotFound – if the instance owning the database does not exist, or if the backup being restored from does not exist
  • ValueError – if backup is not set

property restore_info()

Restore info for this database.

• Return type
  RestoreInfo
• Returns
  an object representing the restore info for this database

run_in_transaction(func, *args, **kw)

Perform a unit of work in a transaction, retrying on abort.

• Parameters
  • func (callable) – takes a required positional argument, the transaction, and additional positional / keyword arguments as supplied by the caller.
  • args (tuple) – additional positional arguments to be passed to func.
  • kw (dict) – (Optional) keyword arguments to be passed to func. If passed, “timeout_secs” will be removed and used to override the default retry timeout which defines maximum timestamp to continue retrying the transaction.
• Return type
  Any
• Returns
  The return value of func.
• Raises
  Exception – reraises any non-ABORT exceptions raised by func.

session(labels=None, database_role=None)

Factory to create a session for this database.

• Parameters
  • labels (dict* (str -> str) or _[_None*](https://python.readthedocs.io/en/latest/library/constants.html#None)) – (Optional) user-assigned labels for the session.
  • database_role (str) – (Optional) user-assigned database_role for the session.
• Return type
  Session
• Returns
  a session bound to this database.

set_iam_policy(policy)

Sets the access control policy on a database resource. Replaces any existing policy.

• Parameters
  policy_version – the complete policy to be applied to the resource.
• Return type
  Policy
• Returns
  returns the new Identity and Access Management (IAM) policy.

snapshot(**kw)

Return an object which wraps a snapshot.

The wrapper must be used as a context manager, with the snapshot as the value returned by the wrapper.

Seehttps://cloud.google.com/spanner/reference/rpc/google.spanner.v1#google.spanner.v1.TransactionOptions.ReadOnly

• Parameters
  kw (dict) – Passed through toSnapshot constructor.
• Return type
  SnapshotCheckout
• Returns
  new wrapper

property spanner_api()

Helper for session-related API calls.

property state()

State of this database.

• Return type
  State
• Returns
  an enum describing the state of the database

table(table_id)

Factory to create a table object within this database.

Note: This method does not create a table in Cloud Spanner, but it can be used to check if a table exists.

my_table = database.table("my_table")
if my_table.exists():
    print("Table with ID 'my_table' exists.")
else:
    print("Table with ID 'my_table' does not exist.")

• Parameters
  table_id (str) – The ID of the table.
• Return type
  Table
• Returns
  a table owned by this database.

update(fields)

Update this database.

Seehttps://cloud.google.com/spanner/reference/rpc/google.spanner.admin.database.v1#google.spanner.admin.database.v1.DatabaseAdmin.UpdateDatabase

NOTE: > Updates the specified fields of a Cloud Spanner database. Currently,

only the enable_drop_protection field supports updates. To change this value before updating, set it via

database.enable_drop_protection = True

before calling update().

• Parameters
  fields (Sequence _[_str]) – a list of fields to update
• Return type
  google.api_core.operation.Operation
• Returns
  an operation instance
• Raises
  NotFound – if the database does not exist

update_ddl(ddl_statements, operation_id='')

Update DDL for this database.

Apply any configured schema from ddl_statements.

Seehttps://cloud.google.com/spanner/reference/rpc/google.spanner.admin.database.v1#google.spanner.admin.database.v1.DatabaseAdmin.UpdateDatabaseDdl

• Parameters
  • ddl_statements (Sequence _[_str]) – a list of DDL statements to use on this database
  • operation_id (str) – (optional) a string ID for the long-running operation
• Return type
  google.api_core.operation.Operation
• Returns
  an operation instance
• Raises
  NotFound – if the database does not exist

property version_retention_period()

The period in which Cloud Spanner retains all versions of data for the database.

• Return type
  str
• Returns
  a string representing the duration of the version retention period

class google.cloud.spanner_v1.database.SnapshotCheckout(database, **kw)

Bases: object

Context manager for using a snapshot from a database.

Inside the context manager, checks out a session from the database, creates a snapshot from it, making the snapshot available.

Caller must not use the snapshot to perform API requests outside the scope of the context manager.

• Parameters
  • database (Database) – database to use
  • kw (dict) – Passed through toSnapshot constructor.

_ enter_()

Begin with block.

_ exit_(exc_type, exc_val, exc_tb)

End with block.