Opportunities used functions and parameters ExternalLangDef

ExternalLangDef is an extension of basic functional language SQLWhereLanguageDef.

The fundamental difference between ExternalLangDef SQLWhereLanguageDef is the possibility of imposing restrictions on detali.

Main features ExternalLangDef

Class ExternalLangDef is the heir SQLWhereLanguageDef, and the job restriction function is also carried out by the method invocation GetFucntion(string, params object;). However, the description of the variable-detail passed to the method parameter, instead of the base class Explanation variables when building the functions, limitations is performed with the help of his heir DetailVariableDef.

Functions restrictions on the existence of datalow

  • funcExistExact
  • funcExistAllExact
  • funcExist
  • funcExistDetails
  • funcExistAll

Read more in article Restrictions on detali.

Functions restrictions on the values of datalow

  • funcMaxWithLimit: the maximum value in detale restriction.
  • funcMinWithLimit: the minimum value in detale restriction.
  • funcAvgWithLimit: the average value in detale restriction.
  • funcSumWithLimit: the sum of the values in detale restriction.
  • string funcCountWithLimit: the number of values in detale restriction.

Function limitations on the date

  • funcYearPart - limitation for the year.
  • funcMonthPart limit for the month.
  • funcDayPart - limit for the day.
  • funcHHPart - maximum hours.
  • funcMIPart - limit for a moment.
  • funcDATEDIFF - restriction on the difference of dates.
  • funcOnlyDate - a date restriction.
  • funcDayOfWeek - limit on the day of the week.
  • funcDayOfWeekZeroBased - limit on the day of the week.
  • funcOnlyTime - restriction on time.
  • funcDateAdd - full analogue of SQL dateadd function.
  • funcDaysInMonth - a limit on the number of days in the month.

For details, see Restriction of operations with date and time.

  • paramTODAY - option to get today’s date.
  • paramYearDIFF parameter to get the value from date.
  • paramMonthDIFF parameter to retrieve the value of month from the date.
  • paramWeekDIFF parameter to get the value of weeks from the date.
  • paramQuarterDIFF parameter to retrieve the value of the quarter of the date.
  • paramDayDIFF parameter to retrieve the value of the day of the date.

For details, see Restriction of operations with date and time.


  • funcToChar function convert an expression to a string.
  • funcCurrentUser
  • funcImplication - function implications.
  • ExternalLangDef.ExistViewName - a string constant that is used to indicate the name of the view when built restrictions on detali.