[seek-dev] What to do about "nil"
Bertram Ludaescher
ludaesch at sdsc.edu
Tue Nov 9 10:52:45 PST 2004
Rod:
Seems that if an empty string is received (denoting nil) than *any*
number you return is wrong. What data structures are allowed on the
"receiving side"? Seems that for a data type that is "nullable" (or
nillable ;-) one needs a union type
type mynillableType = myComplexType | nil
Isn't such a construct available?
B
>>>>> "RS" == Rod Spears <rods at ku.edu> writes:
RS>
RS> Here is the schema for Latitude per the DarwinCore spec:
RS> <xsd:element name="DecimalLatitude"
RS> substitutionGroup="digir:searchableReturnableData" nillable="true">
RS> <xsd:annotation>
RS> <xsd:documentation>The latitude of the location from which
RS> the cataloged item was collected, expressed in decimal
RS> degrees.</xsd:documentation>
RS> </xsd:annotation>
RS> <xsd:simpleType>
RS> <xsd:restriction base="xsd:decimal">
RS> <xsd:minInclusive value="-90.0"/>
RS> <xsd:maxInclusive value="90.0"/>
RS> </xsd:restriction>
RS> </xsd:simpleType>
RS> </xsd:element>
RS>
RS> Note that the value can be "nil" and it also has a restriction. When the
RS> value reaches the DarwinCoreDataSource as a string it is either a valid
RS> number within the range or an empty string (length zero).
RS>
RS> Currently, I convert the empty string to "0.0" which is the wrong thing
RS> to do. The question is what should I do? As Dan suggested I could pick
RS> an arbitray large number and pass that back, but that assumes the
RS> consumer will know what to do with that value. I could skip any and all
RS> rows that have empty Lat or Long values, but that may be bad for
RS> consumers that want to see that data but don't care if it is nil (empty)
RS> or not.
RS>
RS> Any thoughts?
RS>
RS> Rod
RS>
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