Delete graph data with DML

voidDeleteDataWithDml(google::cloud::spanner::Clientclient){
using::google::cloud::StatusOr;
namespacespanner=::google::cloud::spanner;
autocommit_result=client.Commit([&client](spanner::Transactiontxn)
->StatusOr<spanner::Mutations>{
autodeleted=client.ExecuteDml(
std::move(txn),
spanner::SqlStatement(
"DELETE FROM AccountTransferAccount WHERE id = 1 AND to_id = 2"));
if(!deleted)returnstd::move(deleted).status();
returnspanner::Mutations{};
});
if(!commit_result)throwstd::move(commit_result).status();
commit_result=client.Commit(
[&client](spanner::Transactiontxn)->StatusOr<spanner::Mutations>{
autodeleted=client.ExecuteDml(
std::move(txn),
spanner::SqlStatement("DELETE FROM Account WHERE id = 2"));
if(!deleted)returnstd::move(deleted).status();
returnspanner::Mutations{};
});
if(!commit_result)throwstd::move(commit_result).status();
std::cout << "Delete was successful [spanner_delete_graph_data_with_dml]\n";
}

import(
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
)
funcdeleteGraphDataWithDml(wio.Writer,dbstring)error{
ctx:=context.Background()
client,err:=spanner.NewClient(ctx,db)
iferr!=nil{
returnerr
}
deferclient.Close()
// Execute a ReadWriteTransaction to update the 'AccountTransferAccount'
// table underpinning 'AccountTransferAccount' edges in 'FinGraph'. The
// function run by ReadWriteTransaction executes an 'DELETE' SQL DML
// statement. This has the effect of deleting the 'AccountTransferAccount'
// edge where the source 'id' is 1 and the destination 'id' is 2 from the graph.
_,err1:=client.ReadWriteTransaction(ctx,func(ctxcontext.Context,txn*spanner.ReadWriteTransaction)error{
stmt:=spanner.Statement {SQL:`DELETE FROM AccountTransferAccount WHERE id = 1 AND to_id = 2`}
rowCount,err:=txn.Update(ctx,stmt)
iferr!=nil{
returnerr
}
fmt.Fprintf(w,"%d AccountTransferAccount record(s) deleted.\n",rowCount)
returnnil
})
iferr1!=nil{
returnerr1
}
// Execute a ReadWriteTransaction to update the 'Account' table underpinning
//'Account' nodes in 'FinGraph'. In 'FinGraph', nodes can only be deleted
// after any edges referencing the nodes have been deleted first. The function
// run by ReadWriteTransaction executes an 'DELETE' SQL DML statement. This has
// the effect of deleting the 'Account' node whose 'id' is 1 from the graph.
_,err2:=client.ReadWriteTransaction(ctx,func(ctxcontext.Context,txn*spanner.ReadWriteTransaction)error{
stmt:=spanner.Statement {SQL:`DELETE FROM Account WHERE id = 2`}
rowCount,err:=txn.Update(ctx,stmt)
iferr!=nil{
returnerr
}
fmt.Fprintf(w,"%d Account record(s) deleted.\n",rowCount)
returnnil
})
returnerr2
}

staticvoiddeleteUsingDml(DatabaseClientdbClient){
dbClient
.readWriteTransaction()
.run(
transaction->{
Stringsql="DELETE FROM AccountTransferAccount WHERE id = 1 AND to_id = 2";
longrowCount=transaction.executeUpdate(Statement.of(sql));
System.out.printf("%d AccountTransferAccount record(s) deleted.\n",rowCount);
returnnull;
});
dbClient
.readWriteTransaction()
.run(
transaction->{
Stringsql="DELETE FROM Account WHERE id = 2";
longrowCount=transaction.executeUpdate(Statement.of(sql));
System.out.printf("%d Account record(s) deleted.\n",rowCount);
returnnull;
});
}

defdelete_data_with_dml(instance_id, database_id):
"""Deletes sample data from the database using a DML statement."""
 spanner_client = spanner.Client()
 instance = spanner_client.instance(instance_id)
 database = instance.database(database_id)
 defdelete_transfers(transaction):
 row_ct = transaction.execute_update(
 "DELETE FROM AccountTransferAccount WHERE id = 1 AND to_id = 2"
 )
 print("{} AccountTransferAccount record(s) deleted.".format(row_ct))
 defdelete_accounts(transaction):
 row_ct = transaction.execute_update("DELETE FROM Account WHERE id = 2")
 print("{} Account record(s) deleted.".format(row_ct))
 database.run_in_transaction(delete_transfers)
 database.run_in_transaction(delete_accounts)