@google-cloud/spanner 1.5.0 » Class: TransactionRequest

TransactionRequest

class   abstract

Constructor

TransactionRequest

new TransactionRequest(options)

Handle logic for Table/Transaction API operations.

Abstract class extended by Transaction and Table.

Parameter
options	Optional object Timestamp options.

Methods

createReadStream

createReadStream(table, query) returns ReadableStream

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

Wrapper around v1.SpannerClient#streamingRead.

Parameter
table	string The table to read from.
query	ReadStreamRequestOptions Configuration object. See ReadRequest.

See also

v1.SpannerClient#streamingRead

StreamingRead API Documentation

ReadRequest API Documentation

Returns

ReadableStream 

A readable stream that emits rows.

Example

const Spanner = require('@google-cloud/spanner');
const spanner = new Spanner();

const instance = spanner.instance('my-instance');
const database = instance.database('my-database');

database.runTransaction(function(err, transaction) {
  if (err) {
    // Error handling omitted.
  }

  transaction.createReadStream('Singers', {
      keys: ['1'],
      columns: ['SingerId', 'name']
    })
    .on('error', function(err) {})
    .on('data', function(row) {
      // row = [
      //   {
      //     name: 'SingerId',
      //     value: '1'
      //   },
      //   {
      //     name: 'Name',
      //     value: 'Eddie Wilson'
      //   }
      // ]
    })
    .on('end', function() {
      // All results retrieved.
    });
});

//-
// Provide an array for `query.keys` to read with a composite key.
//-
const query = {
  keys: [
    [
      'Id1',
      'Name1'
    ],
    [
      'Id2',
      'Name2'
    ]
  ],
  // ...
};

//-
// Rows are returned as an array of object arrays. Each object has a `name`
// and `value` property. To get a serialized object, call `toJSON()`.
//-
database.runTransaction(function(err, transaction) {
  if (err) {
    // Error handling omitted.
  }

  transaction.createReadStream('Singers', {
      keys: ['1'],
      columns: ['SingerId', 'name']
    })
    .on('error', function(err) {})
    .on('data', function(row) {
      // row.toJSON() = {
      //   SingerId: '1',
      //   Name: 'Eddie Wilson'
      // }
    })
    .on('end', function() {
      // All results retrieved.
    });
});

//-
// Alternatively, set `query.json` to `true`, and this step will be performed
// automaticaly.
//-
database.runTransaction(function(err, transaction) {
  if (err) {
    // Error handling omitted.
  }

  transaction.createReadStream('Singers', {
      keys: ['1'],
      columns: ['SingerId', 'name'],
      json: true,
    })
    .on('error', function(err) {})
    .on('data', function(row) {
      // row = {
      //   SingerId: '1',
      //   Name: 'Eddie Wilson'
      // }
    })
    .on('end', function() {
      // All results retrieved.
    });
});

//-
// If you anticipate many results, you can end a stream early to prevent
// unnecessary processing and API requests.
//-
database.runTransaction(function(err, transaction) {
  if (err) {
    // Error handling omitted.
  }

  transaction.createReadStream('Singers', {
      keys: ['1'],
      columns: ['SingerId', 'name']
    })
    .on('data', function(row) {
      this.end();
    });
});

deleteRows

deleteRows(table, keys)

Delete rows from a table.

Parameter
table	string The name of the table.
keys	array The keys for the rows to delete. If using a composite key, provide an array within this array. See the example below.

See also

Commit API Documentation

Example

const Spanner = require('@google-cloud/spanner');
const spanner = new Spanner();

const instance = spanner.instance('my-instance');
const database = instance.database('my-database');

const keys = ['Id1', 'Id2', 'Id3'];

database.runTransaction(function(err, transaction) {
  if (err) {
    // Error handling omitted.
  }

  // Queue this mutation until later calling `commit`.
  // Note that a callback is not passed to `deleteRows`.
  transaction.deleteRows('Singers', keys);

  // Commit the transaction.
  transaction.commit(function(err) {
    if (!err) {
      // The rows were deleted successfully.
    }
  });
});

//-
// Provide an array for `keys` to delete rows with a composite key.
//-
const keys = [
  [
    'Id1',
    'Name1'
  ],
  [
    'Id2',
    'Name2'
  ]
];

insert

insert(table, keyVals)

Insert rows of data into this table.

Parameter
table	string The name of the table.
keyVals	(object or Array of object) A map of names to values of data to insert into this table.

See also

Commit API Documentation

Example

const Spanner = require('@google-cloud/spanner');
const spanner = new Spanner();

const instance = spanner.instance('my-instance');
const database = instance.database('my-database');

const row = {
  SingerId: 'Id3',
  Name: 'Eddie Wilson'
};

database.runTransaction(function(err, transaction) {
  if (err) {
    // Error handling omitted.
  }

  // Queue this mutation until later calling `commit`.
  // Note that a callback is not passed to `insert`.
  transaction.insert('Singers', row);

  // Commit the transaction.
  transaction.commit(function(err) {
    if (!err) {
      // The row was inserted successfully.
    }
  });
});

//-
// Multiple rows can be inserted at once.
//-
const row2 = {
  SingerId: 'Id3b',
  Name: 'Joe West'
};

database.runTransaction(function(err, transaction) {
  if (err) {
    // Error handling omitted.
  }

  // Queue multiple mutations until later calling `commit`.
  // Note that a callback is not passed to `insert`.
  transaction.insert('Singers', [
    row,
    row2
  ]);

  // Commit the transaction.
  transaction.commit(function(err) {
    if (!err) {
      // The rows were inserted successfully.
    }
  });
});

read

read(table, query, callback) returns Promise containing TransactionRequestReadResponse

Performs a read request against the specified Table.

Wrapper around v1.SpannerClient#read.

Parameter
table	string The table to read from.
query	ReadRequestOptions Configuration object, describing what to read from the table.
callback	Optional TransactionRequestReadCallback Callback function.

See also

v1.SpannerClient#read

Returns

Promise containing TransactionRequestReadResponse 

Example

const Spanner = require('@google-cloud/spanner');
const spanner = new Spanner();

const instance = spanner.instance('my-instance');
const database = instance.database('my-database');

const query = {
  keys: ['1'],
  columns: ['SingerId', 'name']
};

database.runTransaction(function(err, transaction) {
  if (err) {
    // Error handling omitted.
  }

  transaction.read('Singers', query, function(err, rows) {
    if (err) {
      // Error handling omitted.
    }

    const firstRow = rows[0];

    // firstRow = [
    //   {
    //     name: 'SingerId',
    //     value: '1'
    //   },
    //   {
    //     name: 'Name',
    //     value: 'Eddie Wilson'
    //   }
    // ]

    // End the transaction. Note that no callback is provided.
    transaction.end();
  });
});

//-
// Provide an array for `query.keys` to read with a composite key.
//-
const query = {
  keys: [
    [
      'Id1',
      'Name1'
    ],
    [
      'Id2',
      'Name2'
    ]
  ],
  // ...
};

//-
// Rows are returned as an array of object arrays. Each object has a `name`
// and `value` property. To get a serialized object, call `toJSON()`.
//-
database.runTransaction(function(err, transaction) {
  if (err) {
    // Error handling omitted.
  }

  transaction.read('Singers', query, function(err, rows) {
    if (err) {
      // Error handling omitted.
    }

    const firstRow = rows[0];

    // firstRow.toJSON() = {
    //   SingerId: '1',
    //   Name: 'Eddie Wilson'
    // }

    // End the transaction. Note that no callback is provided.
    transaction.end();
  });
});

//-
// Alternatively, set `query.json` to `true`, and this step will be performed
// automaticaly.
//-
database.runTransaction(function(err, transaction) {
  if (err) {
    // Error handling omitted.
  }

  query.json = true;

  transaction.read('Singers', query, function(err, rows) {
    if (err) {
      // Error handling omitted.
    }

    const firstRow = rows[0];

    // firstRow = {
    //   SingerId: '1',
    //   Name: 'Eddie Wilson'
    // }

    // End the transaction. Note that no callback is provided.
    transaction.end();
  });
});

replace

replace(table, keyVals)

Replace rows of data within a table.

Parameter
table	string The table to read from.
keyVals	(object or Array of object) A map of names to values of data to insert into this table.

See also

Commit API Documentation

Example

const Spanner = require('@google-cloud/spanner');
const spanner = new Spanner();

const instance = spanner.instance('my-instance');
const database = instance.database('my-database');

const row = {
  SingerId: 'Id3',
  Name: 'Joe West'
};

database.runTransaction(function(err, transaction) {
  if (err) {
    // Error handling omitted.
  }

  // Queue this mutation until later calling `commit`.
  // Note that a callback is not passed to `replace`.
  transaction.replace('Singers', row);

  // Commit the transaction.
  transaction.commit(function(err) {
    if (!err) {
      // The row was replaced successfully.
    }
  });
});

update

update(table, keyVals)

Update rows of data within a table.

Parameter
table	string The table to read from.
keyVals	(object or Array of object) A map of names to values of data to insert into this table.

See also

Commit API Documentation

Example

const Spanner = require('@google-cloud/spanner');
const spanner = new Spanner();

const instance = spanner.instance('my-instance');
const database = instance.database('my-database');

const row = {
  SingerId: 'Id3',
  Name: 'Joe West'
};

database.runTransaction(function(err, transaction) {
  if (err) {
    // Error handling omitted.
  }

  // Queue this mutation until later calling `commit`.
  // Note that a callback is not passed to `update`.
  transaction.update('Singers', row);

  // Commit the transaction.
  transaction.commit(function(err) {
    if (!err) {
      // The row was updated successfully.
    }
  });
});

upsert

upsert(table, keyVals)

Insert or update rows of data within a table.

Parameter
table	string The table to read from.
keyVals	(object or Array of object) A map of names to values of data to insert into this table.

See also

Commit API Documentation

Example

const Spanner = require('@google-cloud/spanner');
const spanner = new Spanner();

const instance = spanner.instance('my-instance');
const database = instance.database('my-database');

const row = {
  SingerId: 'Id3',
  Name: 'Joe West'
};

database.runTransaction(function(err, transaction) {
  if (err) {
    // Error handling omitted.
  }

  // Queue this mutation until later calling `commit`.
  // Note that a callback is not passed to `upsert`.
  transaction.upsert('Singers', row);

  // Commit the transaction.
  transaction.commit(function(err) {
    if (!err) {
      // The row was updated or inserted successfully.
    }
  });
});