Delete data in a graph

Delete data in a Spanner Graph.

Code sample

C++

To learn how to install and use the client library for Spanner, see Spanner client libraries.

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

void DeleteData(google::cloud::spanner::Client client) {
  namespace spanner = ::google::cloud::spanner;

  // Delete the 'Owns' relationships with key (1,7) and (2,20).
  auto delete_ownerships =
      spanner::DeleteMutationBuilder("PersonOwnAccount",
                                     spanner::KeySet()
                                         .AddKey(spanner::MakeKey(1, 7))
                                         .AddKey(spanner::MakeKey(2, 20)))
          .Build();

  // Delete transfers using the keys in the range [1, 8]
  auto delete_transfer_range =
      spanner::DeleteMutationBuilder(
          "AccountTransferAccount",
          spanner::KeySet().AddRange(spanner::MakeKeyBoundClosed(1),
                                     spanner::MakeKeyBoundOpen(8)))
          .Build();

  // Deletes rows from the Account table and the AccountTransferAccount
  // table, because the AccountTransferAccount table is defined with
  // ON DELETE CASCADE.
  auto delete_accounts_all =
      spanner::MakeDeleteMutation("Account", spanner::KeySet::All());

  // Deletes rows from the Person table and the PersonOwnAccount table,
  // because the PersonOwnAccount table is defined with ON DELETE CASCADE.
  auto delete_persons_all =
      spanner::MakeDeleteMutation("Person", spanner::KeySet::All());

  auto commit_result = client.Commit(
      spanner::Mutations{delete_ownerships, delete_transfer_range,
                         delete_accounts_all, delete_persons_all});
  if (!commit_result) throw std::move(commit_result).status();
  std::cout << "Delete was successful [spanner_delete_graph_data]\n";
}

Go

To learn how to install and use the client library for Spanner, see Spanner client libraries.

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

import (
	"context"
	"io"

	"cloud.google.com/go/spanner"
)

func deleteGraphData(w io.Writer, db string) error {
	ctx := context.Background()
	client, err := spanner.NewClient(ctx, db)
	if err != nil {
		return err
	}
	defer client.Close()

	// Apply a series of mutations to tables underpinning edges and nodes in the
	// example graph. If there are referential integrity constraints defined
	// between edges and the nodes they connect, the edge must be deleted
	// before the nodes that the edge connects are deleted.
	m := []*spanner.Mutation{
		// spanner.Key can be used to delete a specific set of rows.
		// Delete the PersonOwnAccount rows with the key values (1,7) and (2,20).
		spanner.Delete("PersonOwnAccount", spanner.Key{1, 7}),
		spanner.Delete("PersonOwnAccount", spanner.Key{2, 20}),

		// spanner.KeyRange can be used to delete rows with a key in a specific range.
		// Delete a range of rows where the key prefix is >=1 and <8
		spanner.Delete("AccountTransferAccount",
			spanner.KeyRange{Start: spanner.Key{1}, End: spanner.Key{8}, Kind: spanner.ClosedOpen}),

		// spanner.AllKeys can be used to delete all the rows in a table.
		// Delete all Account rows, which will also delete the remaining
		// AccountTransferAccount rows since it was defined with ON DELETE CASCADE.
		spanner.Delete("Account", spanner.AllKeys()),

		// Delete remaining Person rows, which will also delete the remaining
		// PersonOwnAccount rows since it was defined with ON DELETE CASCADE.
		spanner.Delete("Person", spanner.AllKeys()),
	}
	_, err = client.Apply(ctx, m)
	return err
}

Java

To learn how to install and use the client library for Spanner, see Spanner client libraries.

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

static void deleteData(DatabaseClient dbClient) {
  List<Mutation> mutations = new ArrayList<>();

  // KeySet.Builder can be used to delete a specific set of rows.
  // Delete the PersonOwnAccount rows with the key values (1,7) and (2,20).
  mutations.add(
      Mutation.delete(
          "PersonOwnAccount",
          KeySet.newBuilder().addKey(Key.of(1, 7)).addKey(Key.of(2, 20)).build()));

  // KeyRange can be used to delete rows with a key in a specific range.
  // Delete a range of rows where the key prefix is >=1 and <8
  mutations.add(
      Mutation.delete(
          "AccountTransferAccount", KeySet.range(KeyRange.closedOpen(Key.of(1), Key.of(8)))));

  // KeySet.all() can be used to delete all the rows in a table.
  // Delete all Account rows, which will also delete the remaining
  // AccountTransferAccount rows since it was defined with ON DELETE CASCADE.
  mutations.add(Mutation.delete("Account", KeySet.all()));

  // KeySet.all() can be used to delete all the rows in a table.
  // Delete all Person rows, which will also delete the remaining
  // PersonOwnAccount rows since it was defined with ON DELETE CASCADE.
  mutations.add(Mutation.delete("Person", KeySet.all()));

  dbClient.write(mutations);
  System.out.printf("Records deleted.\n");
}

Python

To learn how to install and use the client library for Spanner, see Spanner client libraries.

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

def delete_data(instance_id, database_id):
    """Deletes sample data from the given database.

    The database, table, and data must already exist and can be created using
    `create_database` and `insert_data`.
    """
    spanner_client = spanner.Client()
    instance = spanner_client.instance(instance_id)
    database = instance.database(database_id)

    # Delete individual rows
    ownerships_to_delete = spanner.KeySet(keys=[[1, 7], [2, 20]])

    # Delete a range of rows where the column key is >=1 and <8
    transfers_range = spanner.KeyRange(start_closed=[1], end_open=[8])
    transfers_to_delete = spanner.KeySet(ranges=[transfers_range])

    # Delete Account/Person rows, which will also delete the remaining
    # AccountTransferAccount and PersonOwnAccount rows because
    # AccountTransferAccount and PersonOwnAccount are defined with
    # ON DELETE CASCADE
    remaining_nodes = spanner.KeySet(all_=True)

    with database.batch() as batch:
        batch.delete("PersonOwnAccount", ownerships_to_delete)
        batch.delete("AccountTransferAccount", transfers_to_delete)
        batch.delete("Account", remaining_nodes)
        batch.delete("Person", remaining_nodes)

    print("Deleted data.")

What's next

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