CQL for DataStax Enterprise 6.0 Earlier DSE version Latest 6.0 patch: 6.0.x

Modifying a user-defined type (UDT)

Add or rename fields to a user-defined type (UDT) with the ALTER TYPE command.

Use the ALTER TYPE command to add fields to a user-defined type (UDT) or to rename an existing field in a UDT.

Restriction: Modifying UDTs used in primary keys or index columns is not supported. Changing the field type is not supported.

Tip: Use OpsCenter to view the CQL for a defined UDT in a keyspace.

Procedure

Add a middlename field of type text to the user-defined type cycling.fullname.
```
ALTER TYPE cycling.fullname ADD middlename text;
```
The ALTER TYPE command creates the field metadata and adds the field to the type schema.
To verify the changes, use the DESC TYPE command.
```
DESC TYPE cycling.fullname ;
```
The middlename column appears in the type definition.
```
CREATE TYPE cycling.fullname (
    firstname text,
    lastname text,
    middlename text
);
```
To change the name of an existing field, use the RENAME command.
```
ALTER TYPE cycling.fullname 
RENAME middlename TO middleinitial;
```
Verify the change.
```
DESC TYPE cycling.fullname ;
```
The changed field name middleinitial appears in the type definition.
```
CREATE TYPE cycling.fullname (
    firstname text,
    lastname text,
    middleinitial text
);
```