This class defines the set of common index transformation (or collation) methods.
An index transformation is used to tranform logical data values into
values used by indices.
For example, you may wish that a query by name finds
the same results for both "ELVIS" and "elvis". Using a case-insensitive
index transformation, such as String, will accomplish this. If you want an exact
match, use Exact.
Index transformations are specified via a property's COLLATION parameter. Every datatype
has a default COLLATION value, which matches one of the methods of the
%Collation class.
The COLLATION parameter can be overwritten by an individual property or by
a specific index definition.
Note that changing a property's COLLATION value will corrupt any index values
currently stored for that property and will require you to manually repopulate the
index.
These methods deal with comparing %Library.FilemanDate values with %Library.PosixTime
Compares a %FilemanDate to a %PosixTime value with the = operator.
These methods deal with comparing %Library.FilemanDate values with %Library.TimeStamp
Compares a %FilemanDate to a %TimeStamp value with the = operator.
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These methods deal with comparing %MV.Date values with %Library.Date
The MultiValue start date is 01/01/1968
ObjectScript date is 01/01/1841
To convert an ObjectScript date ($h) to a MultiValue date:
MVdate = ObjectScript date - 46385
To convert a MultiValue date to an ObjectScript date:
ObjectScript date = MVdate + 46385
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Compares a %MV.Date to a %Date value with the = operator.
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These methods deal with comparing %MV.Date values with %Library.TimeStamp
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Compares a %TimeStamp to a %MV.Date value with the = operator.