Data Types：
cql_type ：：=native_type | collection_type | user_defined_type | tuple_type | custom_type
Native Types：
Counters：
counter type is used to define counter columns. 存储64-bit signed integer 并且支持两种操作 incrementing(增值) and decrementing(减值).
注意计数器的值不能被设置：当counter does not exist until first incremented / decremented，第一次increment / decrement 之前的值是0.
Counters 有几点重要限制：
PRIMARY KEY
2）主键的表的所有列为计数器类型，或者没有一个是计数器类型的.
3）Counters 不支持终止.
4）The delete of counters is supported, but is only guaranteed(担保) to work the first time you delete a counter . 换句话说，你不能重复修改 a counter that you have deleted(if you do , proper behavior is not guaranteed).
5）if a counter update fails unexpectedly(timeout or loss of connection) the client has no way to know if the update has been applied or not , In particular，replaying the update may or may not lead to an over count.
Working with timestamps：
Values of the timestamp type are encode as 64-bit signed integers representing a number of milliseconds since the standard base time known as ：January 1 1970
Timestamps can be input in CQL either using their value as an integer ,or using a string that represents as ISO 8601 date. For instance ,all of the values below：
-
1299038700000 -
'2011-02-0304:05+0000' -
'2011-02-0304:05:00+0000' -
'2011-02-0304:05:00.000+0000' -
'2011-02-03T04:05+0000' -
'2011-02-03T04:05:00+0000' -
'2011-02-03T04:05:00.000+0000'
Working with dates：
datetype are encoded as 32-bit unsigned integers representing a number of days with “the epoch” atthe center of the range (2^31). Epoch is January 1st, 1970
timestamp, a date can be input either as aninteger or using a datestring. In the later case, the format should be yyyy-mm-dd (so'2011-02-03' for instance).
Working with times：
timetype are encoded as 64-bit signed integers representing the number of nanoseconds since midnight.
timestamp, a time can be input either as aninteger or using astringrepresenting the time. In the later case, the format should behh:mm:ss[.fffffffff]
-
'08:12:54' -
'08:12:54.123' -
'08:12:54.123456' -
'08:12:54.123456789'
Collections：
CQL supports 3 kind of collections ： Maps Sets Lists
Maps：
A map
