Build a Query object.
**Queries are built with {module:datastore#createQuery} and .**
Package
@google-cloud/datastoreExample
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
(constructor)(scope, namespace, kinds)
constructor
(
scope
?:
Datastore
|
Transaction
,
namespace
?:
string
|
null
,
kinds
?:
string
[]);
Constructs a new instance of the Query
class
Properties
endVal
endVal
:
string
|
Buffer
|
null
;
entityFilters
entityFilters
:
EntityFilter
[];
filters
filters
:
Filter
[];
groupByVal
groupByVal
:
Array
< {}>;
kinds
kinds
:
string
[];
limitVal
limitVal
:
number
;
namespace
namespace
?:
string
|
null
;
offsetVal
offsetVal
:
number
;
orders
orders
:
Order
[];
scope
scope
?:
Datastore
|
Transaction
;
selectVal
selectVal
:
Array
< {}>;
startVal
startVal
:
string
|
Buffer
|
null
;
Methods
end(end)
end
(
end
:
string
|
Buffer
)
:
this
;
Set an ending cursor to a query.
Parameter
Name
Description
end
string | "\"buffer\"".__global.Buffer
Returns
Type
Description
this
{Query}
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(filter)
filter
(
filter
:
EntityFilter
)
:
Query
;
Datastore allows querying on properties. Supported comparison operators are =
, <
, >
, <=
, >=
, !=
, HAS_ANCESTOR
, IN
and NOT_IN
.
*To filter by ancestors, see {module:datastore/query#hasAncestor}.*
Parameter
Name
Description
filter
EntityFilter
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, value)
filter<T
extends
string
> (
property
:
T
,
value
:
AllowedFilterValueType<T>
)
:
Query
;
Parameters
Name
Description
property
T
value
AllowedFilterValueType
<T>
Type Parameter
Name
Description
T
filter(property, operator, value)
filter<T
extends
string
> (
property
:
T
,
operator
:
Operator
,
value
:
AllowedFilterValueType<T>
)
:
Query
;
Parameters
Name
Description
property
T
operator
Operator
value
AllowedFilterValueType
<T>
Type Parameter
Name
Description
T
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}
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}
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}
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}
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}
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
>
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"). "\"stream\"".internal.Transform
{stream}
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}
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 | "\"buffer\"".__global.Buffer
Returns
Type
Description
this
{Query}
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
);
