ALTER TYPE

Modify an existing user-defined type (UDT). Cassandra 2.1 and later.

Restriction: Modifying UDTs used in primary keys or index columns is not supported.

Synopsis

ALTER TYPE field_name 
[ALTER field_name TYPE new_cql_datatype
| ADD (field_name cql_datatype[,...])
| RENAME field_name TO new_field_name[AND ...]]

Table 1. Legend
Syntax conventions	Description
UPPERCASE	Literal keyword.
Lowercase	Not literal.
`Italics`	Variable value. Replace with a user-defined value.
`[]`	Optional. Square brackets ( `[]` ) surround optional command arguments. Do not type the square brackets.
`( )`	Group. Parentheses ( `( )` ) identify a group to choose from. Do not type the parentheses.
`\|`	Or. A vertical bar ( `\|` ) separates alternative elements. Type any one of the elements. Do not type the vertical bar.
`...`	Repeatable. An ellipsis ( `...` ) indicates that you can repeat the syntax element as often as required.
`'Literal string'`	Single quotation ( `'` ) marks must surround literal strings in CQL statements. Use single quotation marks to preserve upper case.
`{ key : value }`	Map collection. Braces ( `{ }` ) enclose map collections or key value pairs. A colon separates the key and the value.
`<datatype1,datatype2>`	Set, list, map, or tuple. Angle brackets ( `< >` ) enclose data types in a set, list, map, or tuple. Separate the data types with a comma.
`cql_statement;`	End CQL statement. A semicolon ( `;` ) terminates all CQL statements.
`[--]`	Separate the command line options from the command arguments with two hyphens ( `--` ). This syntax is useful when arguments might be mistaken for command line options.
`' <schema> ... </schema> '`	Search CQL only: Single quotation marks ( `'` ) surround an entire XML schema declaration.
`@xml_entity='xml_entity_type'`	Search CQL only: Identify the entity and literal value to overwrite the XML element in the schema and solrConfig files.

To make multiple changes to the UDT, use AND between the clauses.

ALTER field_name TYPE new_cql_datatype: Change the data type of a field. Specify the field name and the new cql datatype.
ADD (field_name cql_datatype[,...]): Add fields by entering a field name followed by the data type in a comma separated list; the values for existing rows is set to null.
RENAME field_name TO new_field_name: Enter the old name and new name of the field.

Examples

Changing the data type

To change the type of a field, the field must already exist and be compatible with the new typeCQL type compatibility.

Tip: Carefully choose the data type for each column at the time of table creation.

Change the birthday timestamp to a blob.

ALTER TABLE cycling.cyclist_alt_stats 
ALTER birthday TYPE  blob;

Adding a field

To add a new field to a user defined type, use ALTER TYPE and the ADD keyword. For existing UDTs, the field value is null.

ALTER TYPE fullname ADD middlename text ;

Changing a field name

To change the name of a field in a user-defined type, use the RENAME old_name TO new_name syntax. Rename multiple fields by separating the directives with AND.

Remove name from all the field names the cycling.fullname UDT.

ALTER TYPE cycling.fullname 
RENAME middlename TO middle 
AND lastname to last 
AND firstname to first;

Verify the changes using describe:

desc type cycling.fullname

The new field names appear in the description.

CREATE TYPE cycling.fullname (
    first text,
    last text,
    middle text
);