Class Snapshot

This transaction type provides guaranteed consistency across several reads, but does not allow writes. Snapshot read-only transactions can be configured to read at timestamps in the past.

When finished with the Snapshot, call to release the underlying Session. Failure to do so can result in a Session leak.

**This object is created and returned from .**

[Timestamp Bounds API Documentation](https://cloud.google.com/spanner/docs/timestamp-bounds)

Inheritance

EventEmitter > Snapshot

Package

@google-cloud/spanner!

Constructors

(constructor)(session, options, queryOptions)

constructor(session: Session, options?: TimestampBounds, queryOptions?: IQueryOptions);

Constructs a new instance of the Snapshot class

Parameters

Type	Name	Description
Session	session	The parent Session object.
TimestampBounds	options	Snapshot timestamp bounds.
spannerClient.spanner.v1.ExecuteSqlRequest.IQueryOptions	queryOptions	Default query options to use when none are specified for a query.

Properties

_options

protected _options: spannerClient.spanner.v1.ITransactionOptions;

Property Value

Type	Description
spannerClient.spanner.v1.ITransactionOptions

_seqno

protected _seqno: number;

Property Value

Type	Description
number

ended

ended: boolean;

Property Value

Type	Description
boolean

id

id?: Uint8Array | string;

Property Value

Type	Description
Uint8Array \| string

metadata

metadata?: spannerClient.spanner.v1.ITransaction;

Property Value

Type	Description
spannerClient.spanner.v1.ITransaction

queryOptions

queryOptions?: IQueryOptions;

Property Value

Type	Description
spannerClient.spanner.v1.ExecuteSqlRequest.IQueryOptions

readTimestamp

readTimestamp?: PreciseDate;

Property Value

Type	Description
PreciseDate

readTimestampProto

readTimestampProto?: spannerClient.protobuf.ITimestamp;

Property Value

Type	Description
spannerClient.protobuf.ITimestamp

request

request: (config: {}, callback: Function) => void;

Property Value

Type	Description
(config: {}, callback: Function) => void

requestOptions

requestOptions?: Pick<IRequestOptions, 'transactionTag'>;

Property Value

Type	Description
Pick<google.spanner.v1.IRequestOptions, 'transactionTag'>

requestStream

requestStream: (config: {}) => Readable;

Property Value

Type	Description
(config: {}) => internal.Readable

resourceHeader_

resourceHeader_: {
        [k: string]: string;
    };

Property Value

Type	Description
{ [k: string]: string; }

session

session: Session;

Property Value

Type	Description
Session

Methods

begin(gaxOptions)

begin(gaxOptions?: CallOptions): Promise<BeginResponse>;

Parameter

Type	Name	Description
CallOptions	gaxOptions

Returns

Type	Description
Promise<BeginResponse>

begin(callback)

begin(callback: BeginTransactionCallback): void;

Parameter

Type	Name	Description
BeginTransactionCallback	callback

Returns

Type	Description
void

begin(gaxOptions, callback)

begin(gaxOptions: CallOptions, callback: BeginTransactionCallback): void;

Parameters

Type	Name	Description
CallOptions	gaxOptions
BeginTransactionCallback	callback

Returns

Type	Description
void

configureTagOptions(singleUse, transactionTag, requestOptions)

configureTagOptions(singleUse?: boolean, transactionTag?: string, requestOptions?: {}): IRequestOptions | null;

Parameters

Type	Name	Description
boolean	singleUse
string	transactionTag
{}	requestOptions

Returns

Type	Description
google.spanner.v1.IRequestOptions \| null

createReadStream(table, request)

createReadStream(table: string, request?: ReadRequest): PartialResultStream;

Create a readable object stream to receive rows from the database using key lookups and scans.

Wrapper around .

[StreamingRead API Documentation](https://cloud.google.com/spanner/docs/reference/rpc/google.spanner.v1#google.spanner.v1.Spanner.StreamingRead) [ReadRequest API Documentation](https://cloud.google.com/spanner/docs/reference/rpc/google.spanner.v1#google.spanner.v1.ReadRequest)

PartialResultStream#response PartialResultStream#stats

Parameters

Type	Name	Description
string	table	The table to read from.
ReadRequest	request

Returns

Type	Description
PartialResultStream	{ReadableStream} A readable stream that emits rows.

encodeKeySet(request)

static encodeKeySet(request: ReadRequest): spannerClient.spanner.v1.IKeySet;

Transforms convenience options keys and ranges into a KeySet object.

Parameter

Type	Name	Description
ReadRequest	request	The read request.

Returns

Type	Description
spannerClient.spanner.v1.IKeySet	{object}

encodeParams(request)

static encodeParams(request: ExecuteSqlRequest): {
        params: p.IStruct;
        paramTypes: {
            [field: string]: spannerClient.spanner.v1.Type;
        };
    };

Encodes convenience options param and types into the proto formatted.

Parameter

Type	Name	Description
ExecuteSqlRequest	request	The SQL request.

Returns

Type	Description
{ params: common.IStruct; paramTypes: { [field: string]: google.spanner.v1.Type; }; }	{object}

encodeTimestampBounds(options)

static encodeTimestampBounds(options: TimestampBounds): spannerClient.spanner.v1.TransactionOptions.IReadOnly;

Formats timestamp options into proto format.

Parameter

Type	Name	Description
TimestampBounds	options	The user supplied options.

Returns

Type	Description
spannerClient.spanner.v1.TransactionOptions.IReadOnly	{object}

end()

end(): void;

Let the client know you're done with a particular transaction. This should mainly be called for Snapshot objects, however in certain cases you may want to call them for Transaction objects as well.

Returns

Type	Description
void

read(table, request)

read(table: string, request: ReadRequest): Promise<ReadResponse>;

Parameters

Type	Name	Description
string	table
ReadRequest	request

Returns

Type	Description
Promise<ReadResponse>

read(table, callback)

read(table: string, callback: ReadCallback): void;

Parameters

Type	Name	Description
string	table
ReadCallback	callback

Returns

Type	Description
void

read(table, request, callback)

read(table: string, request: ReadRequest, callback: ReadCallback): void;

Parameters

Type	Name	Description
string	table
ReadRequest	request
ReadCallback	callback

Returns

Type	Description
void

run(query)

run(query: string | ExecuteSqlRequest): Promise<RunResponse>;

Parameter

Type	Name	Description
string \| ExecuteSqlRequest	query

Returns

Type	Description
Promise<RunResponse>

run(query, callback)

run(query: string | ExecuteSqlRequest, callback: RunCallback): void;

Parameters

Type	Name	Description
string \| ExecuteSqlRequest	query
RunCallback	callback

Returns

Type	Description
void

runStream(query)

runStream(query: string | ExecuteSqlRequest): PartialResultStream;

Create a readable object stream to receive resulting rows from a SQL statement.

Wrapper around .

[ExecuteStreamingSql API Documentation](https://cloud.google.com/spanner/docs/reference/rpc/google.spanner.v1#google.spanner.v1.Spanner.ExecuteStreamingSql) [ExecuteSqlRequest API Documentation](https://cloud.google.com/spanner/docs/reference/rpc/google.spanner.v1#google.spanner.v1.ExecuteSqlRequest)

PartialResultStream#response PartialResultStream#stats

Parameter

Type	Name	Description
string \| ExecuteSqlRequest	query	A SQL query or object.

Returns

Type	Description
PartialResultStream	{ReadableStream}