presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/Database.java/Database/setOwnerType
class Database:        public Builder setOwnerType(PrincipalType ownerType)
        {
            requireNonNull(ownerType, "ownerType is null");
            this.ownerType = ownerType;
            return this;
        }