CQL - Practical Cassandra - page 38

CREATE/ALTER KEYSPACE
CREATE KEYSPACE ( Listing 4.2 ) and ALTER KEYSPACE are used to add
or modify top-level strategy options for a collection of tables. When creating a
keyspace, the keyspace name must be alphanumeric with a length of 32 or less.
There are two supported properties for the CREATE / ALTER KEYSPACE com-
mands, replication and durable_writes . When specifying replic-
ation , you may choose one of two options, SimpleStrategy and NetworkTo-
pologyStrategy. SimpleStrategy will create a replication factor that is consistent
across the entire cluster, and the only option available is the replica-
tion_factor , which must be defined. NetworkTopologyStrategy allows you
to decide the replication factor for each individual data center. The dur-
able_writes option specifies whether or not to use the CommitLog when writ-
ing data. This is on by default and should not be turned off as data loss could result
in the event of an outage.
Listing 4.2 Example Usage of CREATE KEYSPACE
Click here to view code image
CREATE KEYSPACE Analytics
WITH replication = {'class': 'SimpleStrategy',
'replication_factor' : 3};
CREATE KEYSPACE Analytics
WITH replication = {'class': 'NetworkTopo-
logyStrategy', 'west' : 1, 'east' : 3}
AND durable_writes = false;
USE
The USE statement ( Listing 4.3 ) switches the keyspace from the one you are work-
ing in. This works exactly like the USE statement in SQL.
Listing 4.3 Example Usage of USE
USE Analytics;