Creating a user-defined type (UDT)

User-Defined Types (UDTs) can be used to attach multiple data fields to a column.

User-defined types (UDTs) can attach multiple data fields, each named and typed, to a single column. The fields used to create a UDT may be any valid data type, including collections and other existing UDTs. After a UDT is created, it can be used to define a table column.

Procedure

Create a user-defined type named basic_info.

CREATE TYPE IF NOT EXISTS cycling.basic_info ( 
  birthday timestamp, 
  nationality text, 
  height text,
  weight text
);

Create a table for storing cyclist data in columns of type basic_info. Use the frozen keyword in the definition of the user-defined type column.

The frozen keyword is not required for UDTs that contain only non-collection fields.

When using the frozen keyword, you cannot update parts of a user-defined type value. The entire value must be overwritten. The database treats the value of a frozen, user-defined type like a blob.
```
CREATE TABLE IF NOT EXISTS cycling.cyclist_stats ( 
  id UUID PRIMARY KEY,
  lastname text,
  basics basic_info
);
```

A user-defined type can be nested in another column type. The example below nests a UDT in a frozen list named races.

CREATE TYPE IF NOT EXISTS cycling.race (
  race_title text,
  race_date timestamp,
  race_time text
);

CREATE TABLE IF NOT EXISTS cycling.cyclist_races (
  id UUID PRIMARY KEY,
  lastname text,
  firstname text,
  races list<FROZEN <race>>
);