ARDBCGetEntryStatistics

Description

This function gathers statistical information about a set of data. The plug-in server calls this function when it receives a request from the AR System server to get entry statistics.

Important

If you do not define this function and the plug-in server receives a get entry statistics request, the AR System server receives an error message and does not retrieve the data.

Synopsis

#include "ardbc.h"

int ARDBCGetEntryStatistics(
  void *object,
  char *tableName,
  ARVendorFieldList *vendorFieldList,
  ARInternalId transId,
  ARQualifierStruct *qualifier,
  ARFieldValueOrArithStruct *target,
  unsigned int statistic,
  ARInternalIdList *groupByList,
  ARStatisticsResultList *results,
  ARStatusList *status)

Input arguments

object

Pointer to the plug-in instance that the call to ARPluginCreateInstance returned.

tableName

Name of the external table from which to retrieve the statistics.

vendorFieldList

List of external form fields. The plug-in uses this list to map AR System field identification numbers (field IDs) to corresponding external form field names.

Note

All other ARDBC input arguments and return values see AR System field IDs, not external form IDs.

transId

Transaction identification number (transaction ID) that the plug-in server designates for each transaction. The transaction ID is unique to the thread that the AR System server uses to access the ARDBC plug-in. There is only one open transaction per server thread.

qualifier

Query that determines the set of entries to retrieve. The qualification can include one or more fields and any combination of conditional, relational, and arithmetic operations (numeric data only).

target

Arithmetic operation that defines the statistic to compute. The statistic can include one or more fields and any combination of arithmetic operations. The system generates an error if the user does not have read permission for a field or if a field does not exist. If you specify AR_STAT_OP_COUNT for the statistic parameter, assign a tag value of 0 to omit this parameter.

statistic

Value that indicates the statistic type.

groupByList

List of zero or more fields to group the results by. The system computes a result for each group of entries having the same value in the specified field. Specifying more than one field creates groups within groups, each of which returns a separate statistic. Specify NULL for this parameter (or zero fields) to compute a single result for all matching entries.

Return values

results

List of zero or more results. If you specify one or more fields for the groupByList parameter, each item in the list represents a group. Each result structure contains the field values that define the group and the statistic for that group.

status

List of zero or more notes, warnings, or errors generated from a call to this function. For a description of all possible values, see Error-checking.