Alter a table column

Use the ALTER TABLE command to add new columns, drop non-primary key columns, or rename a primary key column.

To change the table settings, see Altering table properties.

Add a column

Add an age column of type int to the table cycling.cyclist_alt_stats.

ALTER TABLE cycling.cyclist_alt_stats ADD cyclist_age int;

The ALTER TABLE command creates the column metadata, adds the column to the table schema, and sets the value to null for all rows.

Verify that a column is added

Verify that the column was added with null values.

SELECT id, cyclist_age AS age FROM cycling.cyclist_alt_stats LIMIT 3;
WARNING: cqlsh was built against 5.0-beta1, but this server is 5.0.  All features may not work!

 id                                   | age
 e0953617-07eb-4c82-8f91-3b2757981625 | null
 1ba0417d-62da-4103-b710-de6fb222db6f |   34
 4ceb495c-55ab-4f71-83b9-81117252bf13 |   34

(3 rows)

The result set shows the first three rows.

Rename a column

Rename the id primary key column to cyclist_id.

ALTER TABLE cycling.cyclist_alt_stats RENAME id TO cyclist_id;

Restriction: Only primary key columns can be renamed.

Add a collection column

Alter the table cycling.upcoming_calendar to add a map named description to store a name and description for each race.

ALTER TABLE cycling.upcoming_calendar 
  ADD description map<text,text>;

Verify the collection column

Verify the results:

SELECT * FROM cycling.upcoming_calendar WHERE year = 2015 AND month = 6;

Map type columns display in a JSON format.

WARNING: cqlsh was built against 5.0-beta1, but this server is 5.0.  All features may not work!

 year | month | description                                                                  | events
 2015 |     6 | {'Criterium du Dauphine': 'Easy race', 'Tour du Suisse': 'Hard uphill race'} | ['Tour de France', 'Criterium du Dauphine', 'Vuelta Ciclista a Venezuela']

(1 rows)

See also:

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