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    Property by kind query

    Query property by kind.

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    For detailed documentation that includes this code sample, see the following:

    Code sample

    C#

    To learn how to install and use the client library for Datastore mode, see Datastore mode client libraries . For more information, see the Datastore mode C# API reference documentation .

    To authenticate to Datastore mode, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      Key 
  
 key 
  
 = 
  
 _db 
 . 
 CreateKeyFactory 
 ( 
 "__kind__" 
 ). 
 CreateKey 
 ( 
 "Task" 
 ); 
 Query 
  
 query 
  
 = 
  
 new 
  
 Query 
 ( 
 "__property__" 
 ) 
 { 
  
 Filter 
  
 = 
  
 Filter 
 . 
 HasAncestor 
 ( 
 key 
 ) 
 }; 
 var 
  
 properties 
  
 = 
  
 new 
  
 List<string> 
 (); 
 foreach 
  
 ( 
 Entity 
  
 entity 
  
 in 
  
 _db 
 . 
 RunQuery 
 ( 
 query 
 ). 
 Entities 
 ) 
 { 
  
 string 
  
 kind 
  
 = 
  
 entity 
 . 
 Key 
 . 
 Path 
 [ 
 0 
 ]. 
 Name 
 ; 
  
 string 
  
 property 
  
 = 
  
 entity 
 . 
 Key 
 . 
 Path 
 [ 
 1 
 ]. 
 Name 
 ; 
  
 var 
  
 representations 
  
 = 
  
 entity 
 [ 
 "property_representation" 
 ] 
  
 . 
 ArrayValue 
 . 
 Values 
 . 
 Select 
 ( 
 x 
  
 = 
>  
 x 
 . 
 StringValue 
 ) 
  
 . 
 OrderBy 
 ( 
 x 
  
 = 
>  
 x 
 ); 
  
 properties 
 . 
 Add 
 ( 
 $"{property}:" 
  
 + 
  
 string 
 . 
 Join 
 ( 
 "," 
 , 
  
 representations 
 )); 
 };

    Go

    To learn how to install and use the client library for Datastore mode, see Datastore mode client libraries . For more information, see the Datastore mode Go API reference documentation .

    To authenticate to Datastore mode, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      kindKey 
  
 := 
  
 datastore 
 . 
 NameKey 
 ( 
 "__kind__" 
 , 
  
 "Task" 
 , 
  
 nil 
 ) 
 query 
  
 := 
  
 datastore 
 . 
 NewQuery 
 ( 
 "__property__" 
 ). 
 Ancestor 
 ( 
 kindKey 
 ) 
 type 
  
 Prop 
  
 struct 
  
 { 
  
 Repr 
  
 [] 
 string 
  
 `datastore:"property_representation"` 
 } 
 var 
  
 props 
  
 [] 
 Prop 
 keys 
 , 
  
 err 
  
 := 
  
 client 
 . 
 GetAll 
 ( 
 ctx 
 , 
  
 query 
 , 
  
& props 
 )

    Java

    To learn how to install and use the client library for Datastore mode, see Datastore mode client libraries . For more information, see the Datastore mode Java API reference documentation .

    To authenticate to Datastore mode, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      Key 
  
 key 
  
 = 
  
 datastore 
 . 
 newKeyFactory 
 (). 
 setKind 
 ( 
 "__kind__" 
 ). 
 newKey 
 ( 
 "Task" 
 ); 
 Query<Entity> 
  
 query 
  
 = 
  
 Query 
 . 
 newEntityQueryBuilder 
 () 
  
 . 
 setKind 
 ( 
 "__property__" 
 ) 
  
 . 
 setFilter 
 ( 
 PropertyFilter 
 . 
 hasAncestor 
 ( 
 key 
 )) 
  
 . 
 build 
 (); 
 QueryResults<Entity> 
  
 results 
  
 = 
  
 datastore 
 . 
 run 
 ( 
 query 
 ); 
 Map<String 
 , 
  
 Collection<String> 
>  
 representationsByProperty 
  
 = 
  
 new 
  
 HashMap 
<> (); 
 while 
  
 ( 
 results 
 . 
 hasNext 
 ()) 
  
 { 
  
 Entity 
  
 result 
  
 = 
  
 results 
 . 
 next 
 (); 
  
 String 
  
 propertyName 
  
 = 
  
 result 
 . 
 getKey 
 (). 
 getName 
 (); 
  
 List<StringValue> 
  
 representations 
  
 = 
  
 result 
 . 
 getList 
 ( 
 "property_representation" 
 ); 
  
 Collection<String> 
  
 currentRepresentations 
  
 = 
  
 representationsByProperty 
 . 
 get 
 ( 
 propertyName 
 ); 
  
 if 
  
 ( 
 currentRepresentations 
  
 == 
  
 null 
 ) 
  
 { 
  
 currentRepresentations 
  
 = 
  
 new 
  
 HashSet 
<> (); 
  
 representationsByProperty 
 . 
 put 
 ( 
 propertyName 
 , 
  
 currentRepresentations 
 ); 
  
 } 
  
 for 
  
 ( 
 StringValue 
  
 value 
  
 : 
  
 representations 
 ) 
  
 { 
  
 currentRepresentations 
 . 
 add 
 ( 
 value 
 . 
 get 
 ()); 
  
 } 
 }

    Node.js

    To learn how to install and use the client library for Datastore mode, see Datastore mode client libraries . For more information, see the Datastore mode Node.js API reference documentation .

    To authenticate to Datastore mode, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      async 
  
 function 
  
 runPropertyByKindQuery 
 () 
  
 { 
  
 const 
  
 ancestorKey 
  
 = 
  
 datastore 
 . 
 key 
 ([ 
 '__kind__' 
 , 
  
 'Account' 
 ]); 
  
 const 
  
 query 
  
 = 
  
 datastore 
  
 . 
 createQuery 
 ( 
 '__property__' 
 ) 
  
 . 
 hasAncestor 
 ( 
 ancestorKey 
 ); 
  
 const 
  
 [ 
 entities 
 ] 
  
 = 
  
 await 
  
 datastore 
 . 
 runQuery 
 ( 
 query 
 ); 
  
 const 
  
 representationsByProperty 
  
 = 
  
 {}; 
  
 entities 
 . 
 forEach 
 ( 
 entity 
  
 = 
>  
 { 
  
 const 
  
 key 
  
 = 
  
 entity 
 [ 
 datastore 
 . 
 KEY 
 ]; 
  
 const 
  
 propertyName 
  
 = 
  
 key 
 . 
 name 
 ; 
  
 const 
  
 propertyType 
  
 = 
  
 entity 
 . 
 property_representation 
 ; 
  
 representationsByProperty 
 [ 
 propertyName 
 ] 
  
 = 
  
 propertyType 
 ; 
  
 }); 
  
 console 
 . 
 log 
 ( 
 'Task property representations:' 
 ); 
  
 for 
  
 ( 
 const 
  
 key 
  
 in 
  
 representationsByProperty 
 ) 
  
 { 
  
 console 
 . 
 log 
 ( 
 key 
 , 
  
 representationsByProperty 
 [ 
 key 
 ]); 
  
 } 
  
 return 
  
 representationsByProperty 
 ; 
 }

    PHP

    To learn how to install and use the client library for Datastore mode, see Datastore mode client libraries . For more information, see the Datastore mode PHP API reference documentation .

    To authenticate to Datastore mode, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      $ancestorKey = $datastore->key('__kind__', 'Task'); 
 $query = $datastore->query() 
 ->kind('__property__') 
 ->hasAncestor($ancestorKey); 
 $result = $datastore->runQuery($query); 
 /* @var array<string,string> $properties */ 
 $properties = []; 
 /* @var Entity $entity */ 
 foreach ($result as $entity) { 
 $propertyName = $entity->key()->path()[1]['name']; 
 $propertyType = $entity['property_representation']; 
 $properties[$propertyName] = $propertyType; 
 } 
 // Example values of $properties: ['description' => ['STRING']]

    Python

    To learn how to install and use the client library for Datastore mode, see Datastore mode client libraries . For more information, see the Datastore mode Python API reference documentation .

    To authenticate to Datastore mode, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      from 
  
 google.cloud 
  
 import 
  datastore 
 
 # For help authenticating your client, visit 
 # https://cloud.google.com/docs/authentication/getting-started 
 client 
 = 
  datastore 
 
 . 
  Client 
 
 () 
 ancestor 
 = 
 client 
 . 
  key 
 
 ( 
 "__kind__" 
 , 
 "Task" 
 ) 
 query 
 = 
 client 
 . 
  query 
 
 ( 
 kind 
 = 
 "__property__" 
 , 
 ancestor 
 = 
 ancestor 
 ) 
 representations_by_property 
 = 
 {} 
 for 
 entity 
 in 
 query 
 . 
 fetch 
 (): 
 property_name 
 = 
 entity 
 . 
 key 
 . 
  name 
 
 property_types 
 = 
 entity 
 [ 
 "property_representation" 
 ] 
 representations_by_property 
 [ 
 property_name 
 ] 
 = 
 property_types

    Ruby

    To learn how to install and use the client library for Datastore mode, see Datastore mode client libraries . For more information, see the Datastore mode Ruby API reference documentation .

    To authenticate to Datastore mode, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      ancestor_key 
  
 = 
  
 datastore 
 . 
 key 
  
 "__kind__" 
 , 
  
 "Task" 
 query 
  
 = 
  
 datastore 
 . 
 query 
 ( 
 "__property__" 
 ) 
  
 . 
 ancestor 
 ( 
 ancestor_key 
 ) 
 entities 
  
 = 
  
 datastore 
 . 
 run 
  
 query 
 representations 
  
 = 
  
 entities 
 . 
 each_with_object 
 ({}) 
  
 do 
  
 | 
 entity 
 , 
  
 memo 
 | 
  
 property_name 
  
 = 
  
 entity 
 . 
 key 
 . 
 name 
  
 property_types 
  
 = 
  
 entity 
 [ 
 "property_representation" 
 ] 
  
 memo 
 [ 
 property_name 
 ] 
  
 = 
  
 property_types 
 end

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