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    Class Transaction (6.6.2)

    A transaction is a set of Datastore operations on one or more entities. Each transaction is guaranteed to be atomic, which means that transactions are never partially applied. Either all of the operations in the transaction are applied, or none of them are applied.

    Inheritance

    DatastoreRequest > Transaction

    Package

    @google-cloud/datastore

    Example

     const {Datastore} = require(' @google-cloud/datastore 
');
const datastore = new Datastore 
();
const transaction = datastore. transaction 
();

    Constructors

    (constructor)(datastore, options)

      constructor 
 ( 
 datastore 
 : 
  
 Datastore 
 , 
  
 options 
 ?: 
  
 TransactionOptions 
 );

    Constructs a new instance of the Transaction class

    Parameters
    Name
    Description
    datastore
    Datastore
    options
    TransactionOptions

    Properties

    modifiedEntities_

      modifiedEntities_ 
 : 
  
 ModifiedEntities 
 ;
    Property Value
    Type
    Description
    ModifiedEntities

    namespace

      namespace 
 ?: 
  
 string 
 ;
    Property Value
    Type
    Description
    string

    readOnly

      readOnly 
 : 
  
 boolean 
 ;
    Property Value
    Type
    Description
    boolean

    request

      request 
 : 
  
 Function 
 ;
    Property Value
    Type
    Description
    Function

    skipCommit

      skipCommit 
 ?: 
  
 boolean 
 ;
    Property Value
    Type
    Description
    boolean

    Methods

    commit(gaxOptions)

      commit 
 ( 
 gaxOptions 
 ?: 
  
 CallOptions 
 ) 
 : 
  
 Promise<CommitResponse> 
 ;

    Commit the remote transaction and finalize the current transaction instance.

    If the commit request fails, we will automatically rollback the transaction.

    Parameter
    Name
    Description
    gaxOptions
    CallOptions

    Request configuration options, outlined here: https://googleapis.github.io/gax-nodejs/global.html#CallOptions.

    Returns
    Type
    Description
    Promise < CommitResponse >
    Example 
     const {Datastore} = require(' @google-cloud/datastore 
');
const datastore = new Datastore 
();
const transaction = datastore. transaction 
(); transaction 
.commit((err, apiResponse) => {
  if (err) {
    // Transaction could not be committed.
  }
});

//-
// If the callback is omitted, we'll return a Promise.
//- transaction 
.commit().then((data) => {
  const apiResponse = data[0];
});

    commit(callback)

      commit 
 ( 
 callback 
 : 
  
 CommitCallback 
 ) 
 : 
  
 void 
 ;
    Parameter
    Name
    Description
    callback
    CommitCallback
    Returns
    Type
    Description
    void

    commit(gaxOptions, callback)

      commit 
 ( 
 gaxOptions 
 : 
  
 CallOptions 
 , 
  
 callback 
 : 
  
 CommitCallback 
 ) 
 : 
  
 void 
 ;
    Parameters
    Name
    Description
    gaxOptions
    CallOptions
    callback
    CommitCallback
    Returns
    Type
    Description
    void

    createQuery(kind)

      createQuery 
 ( 
 kind 
 ?: 
  
 string 
 ) 
 : 
  
 Query 
 ;

    Create a query for the specified kind. See {module:datastore/query} for all of the available methods.

    Parameter
    Name
    Description
    kind
    string

    The kind to query.

    Returns
    Type
    Description
    Query

    {Query}

    Example 
     const {Datastore} = require('@google-cloud/datastore');
const datastore = new Datastore();
const transaction = datastore.transaction();

// Run the query inside the transaction.
transaction.run((err) => {
  if (err) {
    // Error handling omitted.
  }
  const ancestorKey = datastore.key(['ParentCompany', 'Alphabet']);

  const query = transaction.createQuery('Company')
      .hasAncestor(ancestorKey);

  query.run((err, entities) => {
    if (err) {
      // Error handling omitted.
    }

    transaction.commit((err) => {
      if (!err) {
        // Transaction committed successfully.
      }
    });
  });
});

// Run the query inside the transaction.with namespace
transaction.run((err) => {
  if (err) {
    // Error handling omitted.
  }
  const ancestorKey = datastore.key(['ParentCompany', 'Alphabet']);

  const query = transaction.createQuery('CompanyNamespace', 'Company')
      .hasAncestor(ancestorKey);

  query.run((err, entities) => {
    if (err) {
      // Error handling omitted.
    }

    transaction.commit((err) => {
      if (!err) {
        // Transaction committed successfully.
      }
    });
  });
});

    createQuery(kind)

      createQuery 
 ( 
 kind 
 ?: 
  
 string 
 []) 
 : 
  
 Query 
 ;
    Parameter
    Name
    Description
    kind
    string[]
    Returns
    Type
    Description
    Query

    createQuery(namespace, kind)

      createQuery 
 ( 
 namespace 
 : 
  
 string 
 , 
  
 kind 
 : 
  
 string 
 ) 
 : 
  
 Query 
 ;
    Parameters
    Name
    Description
    namespace
    string
    kind
    string
    Returns
    Type
    Description
    Query

    createQuery(namespace, kind)

      createQuery 
 ( 
 namespace 
 : 
  
 string 
 , 
  
 kind 
 : 
  
 string 
 []) 
 : 
  
 Query 
 ;
    Parameters
    Name
    Description
    namespace
    string
    kind
    string[]
    Returns
    Type
    Description
    Query

    delete(entities)

      delete 
 ( 
 entities 
 ?: 
  
 Entities 
 ) 
 : 
  
 any 
 ;

    Delete all entities identified with the specified key(s) in the current transaction.

    Parameter
    Name
    Description
    entities
    Entities
    Returns
    Type
    Description
    any
    Example 
     const {Datastore} = require(' @google-cloud/datastore 
');
const datastore = new Datastore 
();
const transaction = datastore. transaction 
(); transaction 
.run((err) => {
  if (err) {
    // Error handling omitted.
  }

  // Delete a single entity.
  transaction.delete(datastore. key 
(['Company', 123]));

  // Delete multiple entities at once. transaction 
.delete([
    datastore. key 
(['Company', 123]),
    datastore. key 
(['Product', 'Computer'])
  ]); transaction 
.commit((err) => {
    if (!err) {
      // Transaction committed successfully.
    }
  });
});

    insert(entities)

      insert 
 ( 
 entities 
 : 
  
 Entities 
 ) 
 : 
  
 void 
 ;

    Maps to , forcing the method to be insert .

    Parameter
    Name
    Description
    entities
    Entities

    Datastore key object(s).

    Returns
    Type
    Description
    void

    rollback(callback)

      rollback 
 ( 
 callback 
 : 
  
 RollbackCallback 
 ) 
 : 
  
 void 
 ;

    Reverse a transaction remotely and finalize the current transaction instance.

    Parameter
    Name
    Description
    callback
    RollbackCallback

    The callback function.

    Returns
    Type
    Description
    void
    Example 
     const {Datastore} = require(' @google-cloud/datastore 
');
const datastore = new Datastore 
();
const transaction = datastore. transaction 
();

transaction.run((err) => {
  if (err) {
    // Error handling omitted.
  }

  transaction.rollback((err) => {
    if (!err) {
      // Transaction rolled back successfully.
    }
  });
});

//-
// If the callback is omitted, we'll return a Promise.
//-
transaction.rollback().then((data) => {
  const apiResponse = data[0];
});

    rollback(gaxOptions)

      rollback 
 ( 
 gaxOptions 
 ?: 
  
 CallOptions 
 ) 
 : 
  
 Promise<RollbackResponse> 
 ;
    Parameter
    Name
    Description
    gaxOptions
    CallOptions
    Returns
    Type
    Description
    Promise < RollbackResponse >

    rollback(gaxOptions, callback)

      rollback 
 ( 
 gaxOptions 
 : 
  
 CallOptions 
 , 
  
 callback 
 : 
  
 RollbackCallback 
 ) 
 : 
  
 void 
 ;
    Parameters
    Name
    Description
    gaxOptions
    CallOptions
    callback
    RollbackCallback
    Returns
    Type
    Description
    void

    run(options)

      run 
 ( 
 options 
 ?: 
  
 RunOptions 
 ) 
 : 
  
 Promise<RunResponse> 
 ;

    Begin a remote transaction. In the callback provided, run your transactional commands.

    Parameter
    Name
    Description
    options
    RunOptions

    Configuration object.

    Returns
    Type
    Description
    Promise < RunResponse >
    Example 
     const {Datastore} = require(' @google-cloud/datastore 
');
const datastore = new Datastore 
();
const transaction = datastore. transaction 
(); transaction 
.run((err, transaction) => {
  // Perform Datastore transactional operations.
  const key = datastore.key(['Company', 123]);

  transaction.get(key, (err, entity) => {
    entity.name = 'Google';

    transaction.save({
      key: key,
      data: entity
    });

    transaction.commit((err) => {
      if (!err) {
        // Data saved successfully.
      }
    });
  });
});

//-
// If the callback is omitted, we'll return a Promise.
//- transaction 
.run().then((data) => {
  const transaction = data[0];
  const apiResponse = data[1];
});

    run(callback)

      run 
 ( 
 callback 
 : 
  
 RunCallback 
 ) 
 : 
  
 void 
 ;
    Parameter
    Name
    Description
    callback
    RunCallback
    Returns
    Type
    Description
    void

    run(options, callback)

      run 
 ( 
 options 
 : 
  
 RunOptions 
 , 
  
 callback 
 : 
  
 RunCallback 
 ) 
 : 
  
 void 
 ;
    Parameters
    Name
    Description
    options
    RunOptions
    callback
    RunCallback
    Returns
    Type
    Description
    void

    save(entities)

      save 
 ( 
 entities 
 : 
  
 Entities 
 ) 
 : 
  
 void 
 ;

    Insert or update the specified object(s) in the current transaction. If a key is incomplete, its associated object is inserted and the original Key object is updated to contain the generated ID.

    This method will determine the correct Datastore method to execute ( upsert , insert , or update ) by using the key(s) provided. For example, if you provide an incomplete key (one without an ID), the request will create a new entity and have its ID automatically assigned. If you provide a complete key, the entity will be updated with the data specified.

    By default, all properties are indexed. To prevent a property from being included in *all* indexes, you must supply an excludeFromIndexes array. See below for an example.

    Parameter
    Name
    Description
    entities
    Entities

    Datastore key object(s).

    Returns
    Type
    Description
    void
    Examples 
     <caption>Save a single entity.</caption>
const {Datastore} = require(' @google-cloud/datastore 
');
const datastore = new Datastore 
();
const transaction = datastore. transaction 
();

// Notice that we are providing an incomplete key. After the transaction is
// committed, the Key object held by the `key` variable will be populated
// with a path containing its generated ID.
//-
const key = datastore. key 
('Company'); transaction 
.run((err) => {
  if (err) {
    // Error handling omitted.
  }

  transaction.save({
    key: key,
    data: {
      rating: '10'
    }
  });

  transaction.commit((err) => {
    if (!err) {
      // Data saved successfully.
    }
  });
}); 

     const {Datastore} = require(' @google-cloud/datastore 
');
const datastore = new Datastore 
();
const transaction = datastore. transaction 
();

// Use an array, `excludeFromIndexes`, to exclude properties from indexing.
// This will allow storing string values larger than 1500 bytes. transaction 
.run((err) => {
  if (err) {
    // Error handling omitted.
  }

  transaction.save({
    key: key,
    excludeFromIndexes: [
      'description',
      'embeddedEntity.description',
      'arrayValue[].description'
    ],
    data: {
      description: 'Long string (...)',
      embeddedEntity: {
        description: 'Long string (...)'
      },
      arrayValue: [
        {
          description: 'Long string (...)'
        }
      ]
    }
  });

  transaction.commit((err) => {
    if (!err) {
      // Data saved successfully.
    }
  });
}); 

     <caption>Save multiple entities at once.</caption>
const {Datastore} = require(' @google-cloud/datastore 
');
const datastore = new Datastore 
();
const transaction = datastore. transaction 
();
const companyKey = datastore. key 
(['Company', 123]);
const productKey = datastore. key 
(['Product', 'Computer']); transaction 
.run((err) => {
  if (err) {
    // Error handling omitted.
  }

  transaction.save([
    {
      key: companyKey,
      data: {
        HQ: 'Dallas, TX'
      }
    },
    {
      key: productKey,
      data: {
        vendor: 'Dell'
      }
    }
  ]);

  transaction.commit((err) => {
    if (!err) {
      // Data saved successfully.
    }
  });
});

    update(entities)

      update 
 ( 
 entities 
 : 
  
 Entities 
 ) 
 : 
  
 void 
 ;

    Maps to , forcing the method to be update .

    Parameter
    Name
    Description
    entities
    Entities

    Datastore key object(s).

    Returns
    Type
    Description
    void

    upsert(entities)

      upsert 
 ( 
 entities 
 : 
  
 Entities 
 ) 
 : 
  
 void 
 ;

    Maps to , forcing the method to be upsert .

    Parameter
    Name
    Description
    entities
    Entities

    Datastore key object(s).

    Returns
    Type
    Description
    void
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