USE keyspace¶

Using a keyspace allows to omit keyspace name in queries.

For example in cqlsh one could write:

cqlsh> SELECT * FROM my_keyspace.table;

 a     | b     |
-------+-------+
 12345 | 54321 |

(1 rows)
cqlsh> USE my_keyspace;
cqlsh:my_keyspace> SELECT * FROM table;

 a     | b     |
-------+-------+
 12345 | 54321 |

(1 rows)

Tables from other keyspaces can still easily be accessed by using their keyspace names.

cqlsh:my_keyspace> SELECT * FROM other_keyspace.other_table;

In the driver this can be achieved using Session::use_keyspace:

session
    .query("INSERT INTO my_keyspace.tab (a) VALUES ('test1')", &[])
    .await?;

session.use_keyspace("my_keyspace", false).await?;

// Now we can omit keyspace name in the query
session
    .query("INSERT INTO tab (a) VALUES ('test2')", &[])
    .await?;

The first argument is the keyspace name.
The second argument states whether this name is case sensitive.

It is also possible to send raw use keyspace query using Session::query instead of Session::use_keyspace such as:

session.query("USE my_keyspace", &[]).await?;

This method has a slightly worse latency than Session::use_keyspace - there are two roundtrips needed instead of one. Therefore, Session::use_keyspace is the preferred method for setting keyspaces.

// lowercase name without case sensitivity will use my_keyspace
session.use_keyspace("my_keyspace", false).await?;

// lowercase name with case sensitivity will use my_keyspace
session.use_keyspace("my_keyspace", true).await?;

// uppercase name without case sensitivity will use my_keyspace
session.use_keyspace("MY_KEYSPACE", false).await?;

// uppercase name with case sensitivity will use MY_KEYSPACE
session.use_keyspace("MY_KEYSPACE", true).await?;