GetFieldAggregations()

Summary

Gets the aggregation rules for a field.

 

Syntax

aggr = GetFieldAggregations(string field_spec)

 

Argument	Contents
field_spec	The field specification

 

Returns

An array of aggregation modes that are set for this field.

 

Notes

• If several records are combined in a one-to-many join, the aggregations array describes how to collapse them for this field. E.g., "Sum" means that the join should contain a new field with the sum of the field field_spec in all the records that were collapsed.

• The returned array can contain an element that is a one-element array with one of the strings "Dom", "Sum", "Min", "Max", or "Count", giving rise to a joined field containing the first value, sum of values, minimum value, maximum value and the number of records, respectively. The returned array can also contain an element that is a two-element array with the strings "Avg" and a field name, where the field name refers to a field containing a weight factor to give a weighted average.

• If a record has a missing value in the field, it will not be included in the aggregation.

• If the input field has no aggregation rules, GetFieldsAggregations() returns null.

Example

// Check whether aggregation of the Population field will include counts

aggr = GetFieldsAggregations("State.Population")

has_max = False

for i=1 to aggr.length do

if aggr[i][1] = "Max" then has_max = True

end

// has_max is True if aggr is of the form aggr = {...,{"Max"}, ...}

if has_max = False then

ShowMessage("Note: A join will not contain a maximum population field.")

 

Error Codes

Error Type	Meaning
NotFound	The specified view or field was not found
Error	Invalid field specification

 

See Also

Function	Summary
FieldsSupportAggregations()	Returns a list of fields that support aggregation rules
GetTableStructure()	Gets a list and description of the fields in a table
JoinViews()	Creates a joined view by linking fields in two existing views
JoinViewsMulti()	Creates a joined view by linking multiple fields in two existing views
ModifyTable()	Modifies the file structure of a dBASE, fixed-format text, or fixed-format binary table