UUID and timeuuid functions
About using Timeuuid functions.
Cassandra 2.0.7 and later includes the uuid()
function. This function
takes no parameters and generates a random Type 4 UUID suitable for use in
INSERT
or SET
statements.
Several timeuuid()
functions are designed for use with the
timeuuid()
type:
dateOf()
Used in a
SELECT
clause, this function extracts the timestamp of atimeuuid
column in a result set. This function returns the extracted timestamp as a date. UseunixTimestampOf()
to get a raw timestamp.now()
In the coordinator node, generates a new unique
timeuuid
in milliseconds when the statement is executed. The timestamp portion of thetimeuuid
conforms to the UTC (Universal Time) standard. This method is useful for inserting values. The value returned bynow()
is guaranteed to be unique.minTimeuuid()
andmaxTimeuuid()
Returns aUUID
-like result given a conditional time component as an argument. For example:SELECT * FROM myTable WHERE t > maxTimeuuid('2013-01-01 00:05+0000') AND t < minTimeuuid('2013-02-02 10:00+0000')
The min/maxTimeuuid example selects all rows where the
timeuuid
column,t
, is strictly later than 2013-01-01 00:05+0000 but strictly earlier than 2013-02-02 10:00+0000. The t >= maxTimeuuid('2013-01-01 00:05+0000') does not select atimeuuid
generated exactly at 2013-01-01 00:05+0000 and is essentially equivalent to t > maxTimeuuid('2013-01-01 00:05+0000').The values returned by
minTimeuuid
andmaxTimeuuid
functions are not trueUUID
s in that the values do not conform to the Time-BasedUUID
generation process specified by the RFC 4122. The results of these functions are deterministic, unlike thenow()
function.unixTimestampOf()
Used in a
SELECT
clause, this functions extracts the timestamp in milliseconds of atimeuuid
column in a result set. Returns the value as a raw, 64-bit integer timestamp.
timeuuid
and timestamp
functions to manipulate dates. The functions can be used in INSERT
,
UPDATE
, and SELECT
statements.toDate(timeuuid)
Converts
timeuuid
todate
in YYYY-MM-DD format.toTimestamp(timeuuid)
Converts
timeuuid
totimestamp
format.toUnixTimestamp(timeuuid)
Converts
timeuuid
toUNIX timestamp
format.toDate(timestamp)
Converts
timestamp
todate
in YYYY-MM-DD format.toUnixTimestamp(timestamp)
Converts timestamp to UNIX timestamp format.
toTimestamp(date)
Converts
date
totimestamp
format.toUnixTimestamp(date)
Converts
date
toUNIX timestamp
format.
CREATE TABLE sample_times (a int, b timestamp, c timeuuid, d bigint, PRIMARY KEY (a,b,c,d));
INSERT INTO sample_times (a,b,c,d) VALUES (1, toUnixTimestamp(now()), 50554d6e-29bb-11e5-b345-feff819cdc9f, toTimestamp(now()));
![](../images/screenshots/timeuuid_functions1.png)
SELECT toDate(c) FROM sample_times;
![](../images/screenshots/timeuuid_functions2.png)