Console
    Contact Us Start free

    Class Query (6.6.2)

    Build a Query object.

    **Queries are built with {module:datastore#createQuery} and .**

    Package

    @google-cloud/datastore

    Example

     const {Datastore} = require(' @google-cloud/datastore 
');
const datastore = new Datastore 
();
const query = datastore.createQuery('AnimalNamespace', 'Lion');

    Constructors

    (constructor)(scope, kinds)

      constructor 
 ( 
 scope 
 ?: 
  
 Datastore 
  
 | 
  
 Transaction 
 , 
  
 kinds 
 ?: 
  
 string 
 [] 
  
 | 
  
 null 
 );

    Constructs a new instance of the Query class

    Parameters
    Name
    Description
    scope
    Datastore | Transaction
    kinds
    string[] | null

    (constructor)(scope, namespace, kinds)

      constructor 
 ( 
 scope 
 ?: 
  
 Datastore 
  
 | 
  
 Transaction 
 , 
  
 namespace 
 ?: 
  
 string 
  
 | 
  
 null 
 , 
  
 kinds 
 ?: 
  
 string 
 []);

    Constructs a new instance of the Query class

    Parameters
    Name
    Description
    scope
    Datastore | Transaction
    namespace
    string | null
    kinds
    string[]

    Properties

    endVal

      endVal 
 : 
  
 string 
  
 | 
  
 Buffer 
  
 | 
  
 null 
 ;
    Property Value
    Type
    Description
    string | __global.Buffer | null

    filters

      filters 
 : 
  
 Filter 
 [];
    Property Value
    Type
    Description
    Filter []

    groupByVal

      groupByVal 
 : 
  
 Array 
< {}>;
    Property Value
    Type
    Description
    Array <{}>

    kinds

      kinds 
 : 
  
 string 
 [];
    Property Value
    Type
    Description
    string[]

    limitVal

      limitVal 
 : 
  
 number 
 ;
    Property Value
    Type
    Description
    number

    namespace

      namespace 
 ?: 
  
 string 
  
 | 
  
 null 
 ;
    Property Value
    Type
    Description
    string | null

    offsetVal

      offsetVal 
 : 
  
 number 
 ;
    Property Value
    Type
    Description
    number

    orders

      orders 
 : 
  
 Order 
 [];
    Property Value
    Type
    Description
    Order []

    scope

      scope 
 ?: 
  
 Datastore 
  
 | 
  
 Transaction 
 ;
    Property Value
    Type
    Description
    Datastore | Transaction

    selectVal

      selectVal 
 : 
  
 Array 
< {}>;
    Property Value
    Type
    Description
    Array <{}>

    startVal

      startVal 
 : 
  
 string 
  
 | 
  
 Buffer 
  
 | 
  
 null 
 ;
    Property Value
    Type
    Description
    string | __global.Buffer | null

    Methods

    end(end)

      end 
 ( 
 end 
 : 
  
 string 
  
 | 
  
 Buffer 
 ) 
 : 
  
 this 
 ;

    Set an ending cursor to a query.

    Parameter
    Name
    Description
    end
    string | __global.Buffer
    Returns
    Type
    Description
    this

    {Query}

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

const cursorToken = 'X';

// Retrieve results limited to the extent of cursorToken.
const endQuery = companyQuery. end 
(cursorToken);

    filter(property, value)

      filter 
 ( 
 property 
 : 
  
 string 
 , 
  
 value 
 : 
  
 {}) 
 : 
  
 Query 
 ;

    Datastore allows querying on properties. Supported comparison operators are = , < , > , <= , and >= . "Not equal" and IN operators are currently not supported.

    *To filter by ancestors, see {module:datastore/query#hasAncestor}.*

    Parameters
    Name
    Description
    property
    string

    The field name.

    value
    {}

    Value to compare property to.

    Returns
    Type
    Description
    Query

    {Query}

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

//-
// List all companies that are located in California.
//-
const caliQuery = query. filter 
(' state 
', 'CA');

//-
// List all companies named Google that have less than 400 employees.
//-
const companyQuery = query
  . filter 
('name', 'Google')
  . filter 
('size', '<', 400);

//-
// To filter by key, use `__key__` for the property name. Filter on keys
// stored as properties is not currently supported.
//-
const key = datastore. key 
(['Company', 'Google']);
const keyQuery = query. filter 
('__key__', key);

    filter(property, operator, value)

      filter 
 ( 
 property 
 : 
  
 string 
 , 
  
 operator 
 : 
  
 Operator 
 , 
  
 value 
 : 
  
 {}) 
 : 
  
 Query 
 ;
    Parameters
    Name
    Description
    property
    string
    operator
    Operator
    value
    {}
    Returns
    Type
    Description
    Query

    groupBy(fieldNames)

      groupBy 
 ( 
 fieldNames 
 : 
  
 string 
  
 | 
  
 string 
 []) 
 : 
  
 this 
 ;

    Group query results by a list of properties.

    Parameter
    Name
    Description
    fieldNames
    string | string[]
    Returns
    Type
    Description
    this

    {Query}

    Example 
     const {Datastore} = require(' @google-cloud/datastore 
');
const datastore = new Datastore 
();
const companyQuery = datastore.createQuery('Company');
const groupedQuery = companyQuery. groupBy 
(['name', 'size']);

    hasAncestor(key)

      hasAncestor 
 ( 
 key 
 : 
  
 Key 
 ) 
 : 
  
 this 
 ;

    Filter a query by ancestors.

    Parameter
    Name
    Description
    key
    Key

    Key object to filter by.

    Returns
    Type
    Description
    this

    {Query}

    Example 
     const {Datastore} = require(' @google-cloud/datastore 
');
const datastore = new Datastore 
();
const query = datastore.createQuery('MyKind');
const ancestoryQuery = query. hasAncestor 
(datastore. key 
(['Parent', 123]));

    limit(n)

      limit 
 ( 
 n 
 : 
  
 number 
 ) 
 : 
  
 this 
 ;

    Set a limit on a query.

    Parameter
    Name
    Description
    n
    number

    The number of results to limit the query to.

    Returns
    Type
    Description
    this

    {Query}

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

// Limit the results to 10 entities.
const limitQuery = companyQuery. limit 
(10);

    offset(n)

      offset 
 ( 
 n 
 : 
  
 number 
 ) 
 : 
  
 this 
 ;

    Set an offset on a query.

    Parameter
    Name
    Description
    n
    number

    The offset to start from after the start cursor.

    Returns
    Type
    Description
    this

    {Query}

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

// Start from the 101st result.
const offsetQuery = companyQuery. offset 
(100);

    order(property, options)

      order 
 ( 
 property 
 : 
  
 string 
 , 
  
 options 
 ?: 
  
 OrderOptions 
 ) 
 : 
  
 this 
 ;

    Sort the results by a property name in ascending or descending order. By default, an ascending sort order will be used.

    Parameters
    Name
    Description
    property
    string

    The property to order by.

    options
    OrderOptions

    Options object.

    Returns
    Type
    Description
    this

    {Query}

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

// Sort by size ascendingly.
const companiesAscending = companyQuery. order 
('size');

// Sort by size descendingly.
const companiesDescending = companyQuery. order 
('size', {
  descending: true
});

    run(options)

      run 
 ( 
 options 
 ?: 
  
 RunQueryOptions 
 ) 
 : 
  
 Promise<RunQueryResponse> 
 ;

    Run the query.

    Parameter
    Name
    Description
    options
    RunQueryOptions

    Optional configuration.

    Returns
    Type
    Description
    Promise < RunQueryResponse >
    Example 
     const {Datastore} = require(' @google-cloud/datastore 
');
const datastore = new Datastore 
();
const query = datastore.createQuery('Company');

query.run((err, entities, info) => {
  // entities = An array of records.

  // Access the Key object for an entity.
  const firstEntityKey = entities[0][datastore.KEY];
});

//-
// A keys-only query returns just the keys of the result entities instead
of
// the entities themselves, at lower latency and cost.
//-
query. select 
('__key__');

query.run((err, entities) => {
  const keys = entities.map((entity) => {
    return entity[datastore.KEY];
  });
});

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

    run(options, callback)

      run 
 ( 
 options 
 : 
  
 RunQueryOptions 
 , 
  
 callback 
 : 
  
 RunQueryCallback 
 ) 
 : 
  
 void 
 ;
    Parameters
    Name
    Description
    options
    RunQueryOptions
    callback
    RunQueryCallback
    Returns
    Type
    Description
    void

    run(callback)

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

    runStream(options)

      runStream 
 ( 
 options 
 ?: 
  
 RunQueryStreamOptions 
 ) 
 : 
  
 import 
 ( 
 "stream" 
 ). 
 Transform 
 ;

    Run the query as a readable object stream.

    Query#runStream

    Parameter
    Name
    Description
    options
    RunQueryStreamOptions

    Optional configuration. See for a complete list of options.

    Returns
    Type
    Description
    import("stream"). internal.Transform

    {stream}

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

query. runStream 
()
  .on('error', console.error)
  .on('data', function (entity) {
    // Access the Key object for this entity.
    const key = entity[datastore. KEY 
];
  })
  .on('info', (info) => {})
  .on(' end 
', () => {
    // All entities retrieved.
  });

//-
// If you anticipate many results, you can end a stream early to prevent
// unnecessary processing and API requests.
//-
query. runStream 
()
  .on('data', function (entity) {
    this. end 
();
  });

    select(fieldNames)

      select 
 ( 
 fieldNames 
 : 
  
 string 
  
 | 
  
 string 
 []) 
 : 
  
 this 
 ;

    Retrieve only select properties from the matched entities.

    Queries that select a subset of properties are called Projection Queries.

    Parameter
    Name
    Description
    fieldNames
    string | string[]

    Properties to return from the matched entities.

    Returns
    Type
    Description
    this

    {Query}

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

// Only retrieve the name property.
const selectQuery = companyQuery. select 
('name');

// Only retrieve the name and size properties.
const selectQuery = companyQuery. select 
(['name', 'size']);

    start(start)

      start 
 ( 
 start 
 : 
  
 string 
  
 | 
  
 Buffer 
 ) 
 : 
  
 this 
 ;

    Set a starting cursor to a query.

    Parameter
    Name
    Description
    start
    string | __global.Buffer
    Returns
    Type
    Description
    this

    {Query}

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

const cursorToken = 'X';

// Retrieve results starting from cursorToken.
const startQuery = companyQuery. start 
(cursorToken);
    Create a Mobile Website
    View Site in Mobile | Classic
    Share by: