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https://issues.apache.org/jira/browse/DRILL-356?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mehant Baid updated DRILL-356:
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Attachment: (was: DRILL-356_1.patch)
> Implement support for Date type
> -------------------------------
>
> Key: DRILL-356
> URL: https://issues.apache.org/jira/browse/DRILL-356
> Project: Apache Drill
> Issue Type: Bug
> Reporter: Mehant Baid
> Assignee: Mehant Baid
>
> Add logic to support the following types in Drill:
> Date - Stores date alone (timezoneless)
> DateTime - Stores date and time (timezoneless)
> Time - Stores time only (timezoneless)
> TimeStamp - Stores date and time, contains timezone information
> Interval - Used to store an interval of time, following are the parameters
> which can combine to form an interval type (year, months, days, hours,
> minutes, seconds, milliseconds)
> IntervalYear - Used to store an interval of time in years, months
> IntervalDay - Stores an interval of time in days to seconds i.e: days, hours,
> minutes, seconds, milliseconds
> Internally Date, DateTime use a long field to store milliseconds. It
> represents time since epoch in UTC.
> Since TimeStamp has a timezone associated with it, it additionally uses an
> int field to store the timezone index. We maintain a static list of all
> existing timezones and the int field within TimeStamp represents an index
> into this list.
> Time uses an integer field to store a given time of day
> Interval type is used to represent a period of time use one or more of the
> following fields: Year, month, day, hour, minute, second, millisecond.
> Internally we convert and store only three fields: months, days,
> milliseconds. There is a one to one mapping available between all possible
> fields and out internal fields. Eg: Year to month is (1 Year = 12 months) and
> so on. IntervalYear and IntervalDay are a simpler version of Interval with a
> subset of the fields.
> We use Joda libraries underneath when we want to perform date arithmetic,
> time zone conversion etc. Although for comparison functions we don't use Joda
> because our internal representation (of milliseconds) is sufficient enough
> for all comparisons.
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