from sqlalchemy import (
  Column,
  Computed,
  MetaData,
  String,
  Table,
)

metadata = MetaData(bind=engine)

singers = Table(
    "Singers",
    metadata,
    Column("SingerId", String(36), primary_key=True, nullable=False),
    Column("FirstName", String(200)),
    Column("LastName", String(200), nullable=False),
    Column("FullName", String(400), Computed("COALESCE(FirstName || ' ', '') || LastName"), nullable=False),
)

metadata.create_all(engine)

    raise exceptions.from_grpc_error(exc) from exc
google.api_core.exceptions.InvalidArgument: 400 Error parsing Spanner DDL statement: CREATE TABLE `Singers` (\n\t`SingerId` STRING(36) NOT NULL, \n\t`FirstName` STRING(200), \n\t`LastName` STRING(200) NOT NULL, \n\t`FullName` STRING(400) AS (COALESCE(FirstName || \' \', \'\') || LastName) STORED NOT NULL\n) PRIMARY KEY (SingerId) : Syntax error on line 5, column 80: Expecting \')\' but found \'NOT\'