Database Reference
In-Depth Information
Choosing between tuples and user-defined
types
As we saw, tuples and user-defined types have a lot in common. In both structures, a
column contains a fixed, predefined set of fields, each of which can have its own type.
Both structures are stored as
frozen
, meaning that Cassandra cannot perform discrete op-
erations on their internal components. Both can be indexed and used in the
WHERE
clause
of a query. So how do we decide which to use?
In most cases, a user-defined type is a better option. User-defined types give names to their
fields, making it easier for application developers to reason about their usage. Also, user-
defined types can be partially selected in queries; tuples cannot.
The only reason to use a tuple is convenience: a tuple does not need to be defined separ-
ately from its use in a column definition. So, for quick prototyping of schema structures, a
tuple can be a better option. However, for a schema that's going into production, a user-
defined type is nearly always going to be the right choice.
