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.
google.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
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
ITransaction

queryOptions

queryOptions?: IQueryOptions;
Property Value
Type Description
google.spanner.v1.ExecuteSqlRequest.IQueryOptions

readTimestamp

readTimestamp?: PreciseDate;
Property Value
Type Description
PreciseDate

readTimestampProto

readTimestampProto?: spannerClient.protobuf.ITimestamp;
Property Value
Type Description
ITimestamp

request

request: (config: {}, callback: Function) => void;
Property Value
Type Description
(config: {}, callback: Function) => void

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

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
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
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}