This property is valid when a Storage object is the Query's source (this is indicated by the DataSource property). It specifies a function that defines data generated by this Query. Some functions contain sub-functions, which can be indicated in the FunctionSubType property. The FunctionType property can assume the values described on the next table.
Available options for FunctionType
Option |
Description |
|---|---|
-1 - ftNoFunction |
There is no defined function (default). This value is not available when the QueryType property is configured to 1 - qtStorage |
0 - ftLastValue |
Returns the last value stored on the Database |
1 - ftArchivedValue |
Returns a stored value relative to a certain timestamp defined in the TimeStamp variable. The type of relationship is specified in the FunctionSubType property |
2 - ftTagAttribute |
Returns a Tag attribute, defined in the FunctionSubType property |
3 - ftCompressedDataNValues |
Returns, for a single Tag, N values defined in the NumVals variable, stored from an initial time defined in the StartTime variable |
4 - ftCompressedDataStartEndTime |
Returns, for a single Tag, all values stored at the interval between StartTime and EndTime variables |
5 - ftSampledData |
Returns, for one or more Tags, the interpolated values, that is, estimated at the interval between StartTime and EndTime variables, in fixed intervals defined by the TimeInterval variable |
6 - ftCalculatedData |
Returns, for one or more Tags, the result of math operations applied to data at the interval between StartTime and EndTime variables, in fixed intervals defined by the TimeInterval variable |
NOTE |
Variables can also be defined at run time using the Query's SetVariableValue method. |