Aggregations

An aggregation is a data provider which represents a database column that is aggregated over a set of records. At design-time aggregations have the following properties:

• Name - The name by which the aggregation will be available as a data provider throughout the solution in which it is declared, as well as any modules containing it.
• Type - There are five types of aggregations:
  • Count - The number of records in an entire foundset containing a non-null value for a column
  • Sum - The sum of all the values for numeric column in an entire foundset
  • Minimum - The smallest value for a numeric column in an entire foundset
  • Maximum - The largest value for a numeric column in an entire foundset
  • Average - The average value for a numeric column in an entire foundset
• Column - The column containing values that are aggregated

At runtime, aggregations are computed in the context of a foundset. The value is derived from a SQL query, which takes the form of a SQL Aggregate Function and appends the WHERE clause used by the foundset's query.

Example

Assume an aggregation, record_count, declared on the customer table. The aggregation type is count and the column is customerid. The aggregation is available for any foundset based on the customers table.

function printRecordCcount(event) {function printRecordCcount(event) {
	application.output(record_count);		// print record count before find
	if(foundset.find()){				// Find all customers where city starts with 'B'
		city = 'B%';
		foundset.search();
		application.output(record_count);	// print the record count after find
	}
}

After the find, the aggregation is re-queried using the foundset's new WHERE clause.

SELECT COUNT(customerid) AS record_count FROM customers WHERE city LIKE ? LIMIT ?