Method: projects.beginTransaction

HTTP request
Path parameters
Request body
- JSON representation
Response body
- JSON representation
Authorization scopes
TransactionOptions
- JSON representation
ReadWrite
- JSON representation
ReadOnly
- JSON representation
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Begins a new transaction.

HTTP request

POST https://datastore.googleapis.com/v1beta3/projects/{projectId}:beginTransaction

The URL uses gRPC Transcoding syntax.

Path parameters

Parameters

Parameters
`projectId`	`string` Required. The ID of the project against which to make the request.

projectId

string

Required. The ID of the project against which to make the request.

Request body

The request body contains data with the following structure:

JSON representation
{ "transactionOptions" : { object ( `TransactionOptions` ) } }

Fields

Fields
`transactionOptions`	`object ( TransactionOptions )` Options for a new transaction.

transactionOptions

object ( TransactionOptions )

Options for a new transaction.

Response body

The response for Datastore.BeginTransaction .

If successful, the response body contains data with the following structure:

JSON representation
{ "transaction" : string }

Fields

Fields
`transaction`	`string ( bytes format)` The transaction identifier (always present). A base64-encoded string.

transaction

string ( bytes format)

The transaction identifier (always present).

A base64-encoded string.

Authorization scopes

Requires one of the following OAuth scopes:

https://www.googleapis.com/auth/datastore
https://www.googleapis.com/auth/cloud-platform

For more information, see the Authentication Overview .

TransactionOptions

Options for beginning a new transaction.

Transactions can be created explicitly with calls to Datastore.BeginTransaction or implicitly by setting ReadOptions.new_transaction in read requests.

JSON representation
{ // Union field `mode` can be only one of the following: "readWrite" : { object ( `ReadWrite` ) } , "readOnly" : { object ( `ReadOnly` ) } // End of list of possible types for union field `mode` . }

Fields

Union field mode . The mode of the transaction, indicating whether write operations are supported. mode can be only one of the following:

readWrite

object ( ReadWrite )

The transaction should allow both reads and writes.

readOnly

object ( ReadOnly )

The transaction should only allow reads.

ReadWrite

Options specific to read / write transactions.

JSON representation
{ "previousTransaction" : string }

Fields

Fields
`previousTransaction`	`string ( bytes format)` The transaction identifier of the transaction being retried. A base64-encoded string.

previousTransaction

string ( bytes format)

The transaction identifier of the transaction being retried.

A base64-encoded string.

ReadOnly

Options specific to read-only transactions.

JSON representation
{ "readTime" : string }

Fields

Fields
`readTime`	`string ( Timestamp format)` Reads entities at the given time. This must be a microsecond precision timestamp within the past one hour, or if Point-in-Time Recovery is enabled, can additionally be a whole minute timestamp within the past 7 days. Uses RFC 3339, where generated output will always be Z-normalized and use 0, 3, 6 or 9 fractional digits. Offsets other than "Z" are also accepted. Examples: `"2014-10-02T15:01:23Z"` , `"2014-10-02T15:01:23.045123456Z"` or `"2014-10-02T15:01:23+05:30"` .

readTime

string ( Timestamp format)

Reads entities at the given time.

This must be a microsecond precision timestamp within the past one hour, or if Point-in-Time Recovery is enabled, can additionally be a whole minute timestamp within the past 7 days.

Uses RFC 3339, where generated output will always be Z-normalized and use 0, 3, 6 or 9 fractional digits. Offsets other than "Z" are also accepted. Examples: "2014-10-02T15:01:23Z" , "2014-10-02T15:01:23.045123456Z" or "2014-10-02T15:01:23+05:30" .