dataset_field_exists function

Category:

Database related

General

Checks the presence of the field in the dataset.

Syntax

dataset_field_exists(
  StepNo Integer,
  FieldName String
): Boolean

Parameters

StepNo specifies the step (pass) in which the function must be calculated. Possible values: 1 or 2. When it equals to 1, the corresponding function will be calculated immediately when the expression is processed. When it equals to 2, report will run in double-pass mode and the corresponding function will be calculated only in the second pass of the report processing, i.e. after the report dataset reaches the last record. Using database functions in the second pass is useful, for example, when it is needing to put the report totals in the report or group headers.

Combining different StepNo parameters in one expression (for example, database_field_val(1, 'total_sum') + database_field_val(2, 'payment_sum')) is possible, but such expression should be written so that functions with smaller StepNo will be calculated earlier.

FieldName is the name of the field to check.

Return value

Type: Boolean. Returns True, when the field is present in the current dataset, and False in other cases.

Examples of using

dataset_field_exists(1, 'Salary')