In Cassandra a table contains the timestamp to represent date and time that a write operation was performed on a column or cell. The WRITETIME() function returns the timestamp of when a column was last written to (in milliseconds since the Unix epoch). However, the proxy does not maintain column-level timestamps; instead, it tracks timestamps at the row level using the last_commit_ts column. Consequently, if any column in a row is updated, the WRITETIME() function will return the updated timestamp for all columns in the row, regardless of whether they were modified or not.
For instance, the query select WRITETIME(userid) from test.users would return the last time the row was updated. If the firstname column is subsequently updated, and the previous query is executed again, the returned timestamp would be the updated time, which may not be the expected behavior in Cassandra.
The proxy supports IF NOT EXISTS in the INSERT statements. Similar to Cassandra, Without IF NOT EXISTS, the command/query proceeds with no standard output. If IF NOT EXISTS returns true (if there is no row with this primary key), standard output displays a table like the following:
[applied]
-----------------------
True
If, however, the row does already exist, the command/query fails, and standard out displays a table with the value false in the [applied] column, (however, unlike Cassandra, proxy will not show the values that were not inserted), as in the following example:
[applied]
-----------------------
False