Update graph data with a graph query

  void 
  
 UpdateDataWithGraphQueryInDml 
 ( 
 google 
 :: 
 cloud 
 :: 
 spanner 
 :: 
 Client 
  
 client 
 ) 
  
 { 
  
 using 
  
 :: 
 google 
 :: 
 cloud 
 :: 
 StatusOr 
 ; 
  
 namespace 
  
 spanner 
  
 = 
  
 :: 
 google 
 :: 
 cloud 
 :: 
 spanner 
 ; 
  
 auto 
  
 commit_result 
  
 = 
  
 client 
 . 
 Commit 
 ( 
  
 [ 
& client 
 ]( 
 spanner 
 :: 
 Transaction 
  
 txn 
 ) 
  
 - 
>  
 StatusOr<spanner 
 :: 
 Mutations 
>  
 { 
  
 auto 
  
 update 
  
 = 
  
 client 
 . 
 ExecuteDml 
 ( 
 std 
 :: 
 move 
 ( 
 txn 
 ), 
  
 spanner 
 :: 
 SqlStatement 
 ( 
 R 
 " 
 ""( 
 UPDATE Account SET is_blocked = true 
 WHERE id IN { 
 GRAPH FinGraph 
 MATCH (a:Account WHERE a.id = 1)-[:TRANSFERS]->{1,2}(b:Account) 
 RETURN b.id} 
 )"" 
 " 
 )); 
  
 if 
  
 ( 
 ! 
 update 
 ) 
  
 return 
  
 std 
 :: 
 move 
 ( 
 update 
 ). 
 status 
 (); 
  
 return 
  
 spanner 
 :: 
 Mutations 
 {}; 
  
 }); 
  
 if 
  
 ( 
 ! 
 commit_result 
 ) 
  
 throw 
  
 std 
 :: 
 move 
 ( 
 commit_result 
 ). 
 status 
 (); 
  
 std 
 :: 
 cout 
 << 
 "Update was successful " 
 << 
 "[spanner_update_graph_data_with_graph_query_in_dml] 
 \n 
 " 
 ; 
 } 
 

  import 
  
 ( 
  
 "context" 
  
 "fmt" 
  
 "io" 
  
 "cloud.google.com/go/spanner" 
 ) 
 func 
  
 updateGraphDataWithGraphQueryInDml 
 ( 
 w 
  
 io 
 . 
 Writer 
 , 
  
 db 
  
 string 
 ) 
  
 error 
  
 { 
  
 ctx 
  
 := 
  
 context 
 . 
 Background 
 () 
  
 client 
 , 
  
 err 
  
 := 
  
 spanner 
 . 
 NewClient 
 ( 
 ctx 
 , 
  
 db 
 ) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 return 
  
 err 
  
 } 
  
 defer 
  
 client 
 . 
 Close 
 () 
  
 // Execute a ReadWriteTransaction to update the 'Account' table underpinning 
  
 // 'Account' nodes in 'FinGraph'. The function run by ReadWriteTransaction 
  
 // executes an 'UPDATE' SQL DML statement. Graph queries run after this 
  
 // transaction is committed will observe the effects of the updates to 'Account's 
  
 // 
  
 // The update is performed for all 'Account's whose 'id' is returned by 
  
 // the graph query in the 'IN' subquery, i.e., all 'Account's that have 
  
 // received transfers directly or via one intermediary from an 'Account' 
  
 // whose 'id' is 1. 
  
 _ 
 , 
  
 err 
  
 = 
  
 client 
 . 
 ReadWriteTransaction 
 ( 
 ctx 
 , 
  
 func 
 ( 
 ctx 
  
 context 
 . 
 Context 
 , 
  
 txn 
  
 * 
 spanner 
 . 
 ReadWriteTransaction 
 ) 
  
 error 
  
 { 
  
 stmt 
  
 := 
  
 spanner 
 . 
  Statement 
 
 { 
  
 SQL 
 : 
  
 `UPDATE Account SET is_blocked = true 
 WHERE id IN { 
 GRAPH FinGraph 
 MATCH (a:Account WHERE a.id = 1)-[:TRANSFERS]->{1,2}(b:Account) 
 RETURN b.id}` 
 , 
  
 } 
  
 rowCount 
 , 
  
 err 
  
 := 
  
 txn 
 . 
 Update 
 ( 
 ctx 
 , 
  
 stmt 
 ) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 return 
  
 err 
  
 } 
  
 fmt 
 . 
 Fprintf 
 ( 
 w 
 , 
  
 "%d Account record(s) updated.\n" 
 , 
  
 rowCount 
 ) 
  
 return 
  
 err 
  
 }) 
  
 return 
  
 err 
 } 
 

  static 
  
 void 
  
 updateUsingGraphQueryInDml 
 ( 
 DatabaseClient 
  
 dbClient 
 ) 
  
 { 
  
 dbClient 
  
 . 
 readWriteTransaction 
 () 
  
 . 
 run 
 ( 
  
 transaction 
  
 - 
>  
 { 
  
 String 
  
 sql 
  
 = 
  
 "UPDATE Account SET is_blocked = true " 
  
 + 
  
 "WHERE id IN {" 
  
 + 
  
 "  GRAPH FinGraph" 
  
 + 
  
 "  MATCH (a:Account WHERE a.id = 1)-[:TRANSFERS]->{1,2}(b:Account)" 
  
 + 
  
 "  RETURN b.id}" 
 ; 
  
 long 
  
 rowCount 
  
 = 
  
 transaction 
 . 
 executeUpdate 
 ( 
 Statement 
 . 
 of 
 ( 
 sql 
 )); 
  
 System 
 . 
 out 
 . 
 printf 
 ( 
 "%d Account record(s) updated.\n" 
 , 
  
 rowCount 
 ); 
  
 return 
  
 null 
 ; 
  
 }); 
 } 
 

  def 
  
 update_data_with_graph_query_in_dml 
 ( 
 instance_id 
 , 
 database_id 
 ): 
  
 """Updates sample data from the database using a DML statement.""" 
 spanner_client 
 = 
 spanner 
 . 
 Client 
 () 
 instance 
 = 
 spanner_client 
 . 
 instance 
 ( 
 instance_id 
 ) 
 database 
 = 
 instance 
 . 
 database 
 ( 
 database_id 
 ) 
 def 
  
 update_accounts 
 ( 
 transaction 
 ): 
 row_ct 
 = 
 transaction 
 . 
 execute_update 
 ( 
 "UPDATE Account SET is_blocked = true " 
 "WHERE id IN {" 
 "  GRAPH FinGraph" 
 "  MATCH (a:Account WHERE a.id = 1)-[:TRANSFERS]->{1,2}(b:Account)" 
 "  RETURN b.id}" 
 ) 
 print 
 ( 
 " 
 {} 
 Account record(s) updated." 
 . 
 format 
 ( 
 row_ct 
 )) 
 database 
 . 
 run_in_transaction 
 ( 
 update_accounts 
 )