Add Column to Existing Table in Cassandra by using CQL
It is very easy to add new column/s to existing table in Cassandra.
Syntax:
You can see that I am already in TechBrothersTutorials keyspace. You can "Use Keyspace" to change to keyspace where your table is before running Alter table statement or you can use Full qualified name.
CQLSH:techbrotherstutorials>ALTER Table tablename ADD columnname datatype;
Example:
Let's create Employee table with below definition and then we will use Alter statment to add "PhoneNumber" column.
CQLSH:techbrotherstutorials>CREATE TABLE employee
(
employeeid UUID PRIMARY KEY,
fname TEXT,
lname TEXT,
address TEXT,
age TINYINT
);
(
employeeid UUID PRIMARY KEY,
fname TEXT,
lname TEXT,
address TEXT,
age TINYINT
);
Add PhoneNumber column to Employee table.
CQLSH:techbrotherstutorials>ALTER TABLE employee ADD phonenumber VARCHAR;
Note that the newly added column will have Null values for exiting records. You can verify the definition of table has change correctly by using Describe Table statement.
CQLSH:techbrotherstutorials>describe TABLE employee;