Jarrod Roberson (el 2006-11-09 a les 14:31:05 -0500) va dir:: > I am trying to create a property storage system for a webdav implementation. > > class Property(IsDescription): > name = StringCol(256) > value = StringCol(4096) > > I am using Property to create a table to store my data in. > > I also want to support "versioning" of the values. > > Is there a way to create a value field that can be "muli-valued" or > "multi-dimensional" to so > I can just continue to append data to that column?
Hi Jarrod,
If I understood your problem well, you could simply add a column
containing a timestamp for the particular name-value pair, and store
different versions of it in different rows of the same table. For
instance::
class VersionedProperty(IsDescription):
time = Time64Col()
name = StringCol(256)
value = StringCol(4096)
Then, to get the last value of a property by its name (assuming that
they appear ordered by time in the table)::
namecond = propstbl.cols.name == 'somename'
propidx = propstbl.getWhereList(namecond, sort=True)[-1]
propvalue = propstbl.read(propidx, field='value')
Hope that helps,
::
Ivan Vilata i Balaguer >qo< http://www.carabos.com/
Cárabos Coop. V. V V Enjoy Data
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