A Cassandra Column Family is similar to a table in a relational database management system. However, unlike relational tables, Column Families only define metadata of the columns as described below when creating a Column Family. The actual columns in a row are defined typically by the client application. The actual columns of each row can vary from each other depending on the data stored in a row. For an example of adding data to Cassandra Column Families through a client application, refer to Cassandra Keysapce and Column Family Operations sample.
Note that as a user, you need to be assigned to a role with the relevant authority in order to create or edit column families. The Admin user is by default granted authority to perform this task. See more information about managing users and roles.
Follow the steps below to add column families to an existing keyspace. Also see, Creating Keyspaces.
- Click List under Cassandra Keyspaces and select a keyspace to add column families.
Click Add a New Column Family to open the New Column Family window where you can enter column family details to the keyspace.
The fields of the new column family window are described below:
Fields Description Name* Column Family (CF) Name is mandatory. Must not contain the character "-". Comment Description of the column family.
Used to attach additional human-readable information about the column family to its definition
- Standard Column Family
- Super Column Family
Key Validation Class Datatype of Row keys Comparator Datatype of Column keys Default Validation Class Default datatype of Column values
- Click Save after adding column family details. The Keyspace Information window opens with links to column family operations such as Set Permissions, Edit or Delete.
Click on the Column Family's name and then the Add New Index/Non-Index Column link to create an indexed or non-indexed column.
Field Description Required/Optional Name Name of the new column Required Index Name Index Name Required (only in case of an index column) Validation Class Datatype of column value Required
There are 2 ways of defining a column.
1) Create a (non-indexed) column with a Validation class: Do not specify any values for 'Index Name'.
2) Create an indexed column with a Validation class: Specify a name for the Index in 'Index Name'.