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What is the implementation of the deprecated DateTime datatype?
The deprecated DateTime data type has the tag value -15. The suggested alternative is the Timestamp data type, which has tag value -12. In both cases, the following documentation page states that the size is 8 bytes.
https://code.kx.com/q/basics/datatypes/
However, on this documentation page
Data types | Basics | kdb+ and q documentation – kdb+ and q documentation
the following is stated:
The 4-byte datetime datatype (15) is deprecated in favour of the 8-byte timestamp datatype (12).
Internally, dates, times and timestamps are represented by integers:
This suggests that the deprecated DateTime datatype is a 4 byte integer.
On another documentation page
2. Basic Data Types – Atoms – Q for Mortals
the following is written.
A datetime value stores in a float the fractional day count from midnight Jan 1, 2000.
Combining this with the above, it is unclear as to whether the deprecated Datetime (-15) type is a 4 byte or 8 byte floating point value.
Is anyone able to clarify?
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2 Replies
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Datetime is an backed by an 8 byte float.
The sz column is correct at the top of the page for datetime:
https://code.kx.com/q/basics/datatypes/
The incorrect 4 byte reference will be removed:
https://github.com/KxSystems/docs/pull/359
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This reply was modified 1 month, 1 week ago by rocuinneagain.
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Thank you!
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This reply was modified 1 month, 1 week ago by
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