Create a keyspace

In Cassandra and DataStax Enterprise, the first schema to create is a keyspace using CQL.

Prerequisites

Determine the number of datacenters and replication strategy.
Determine the required replication factor.

Keyspace and table name conventions:

The name of a keyspace or a table is a string of alphanumeric characters and underscores, but it must begin with a letter. If case must be maintained, the name must be encased in double quotes, such as "MyTable".

Since tables are defined within a keyspace, you can either use the keyspace as part of the table creation command, or create a table in the current keyspace. To specify the keyspace as part of a table name, use the keyspace name, a period (.), and table name, such as cycling.cyclist-stats.

Simple keyspace

Start cqlsh and create a keyspace.

CREATE KEYSPACE IF NOT EXISTS cycling
WITH REPLICATION = {
  'class' : 'SimpleStrategy',
  'replication_factor' : 1
};

The keyspace name, replication class, and replication factor must all be specified.

NTS keyspace

Start cqlsh and create a keyspace.
```
CREATE KEYSPACE cycling 
WITH REPLICATION = { 
  'class' : 'NetworkTopologyStrategy', 
  'dc1' : 1
};
```
The keyspace name, replication class, and replication factor must all be specified.

Keyspace with datacenters

Verify the datacenter name or names using nodetool status.
```
nodetool status
```

Datacenter: datacenter1
================
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
--  Address         Load       Tokens       Owns    Host ID                               Rack
UN  10.200.181.134  4.97 MiB   1            ?       c9027497-011c-4390-ae59-e4ed1ac794cc  rack1
UN  10.200.181.135  5.16 MiB   1            ?       af2af8ec-5fa2-4a04-ac9c-c75669d8d3a0  rack1

+ Ensure that the datacenter name matches exactly in the next step, as the name is case-sensitive.

Start cqlsh and create a keyspace.
```
  CREATE KEYSPACE IF NOT EXISTS cycling
  WITH REPLICATION = {
    'class' : 'NetworkTopologyStrategy',
    'datacenter1': '3', 
    'datacenter2': '3'
  };
```
The keyspace name, replication class, and replication factor must all be specified. The replication factor is set for each datacenter.

Use created keyspace

Switch to the keyspace:

  USE cycling;