4.2.3.49 DeleteFrom

DeleteFrom function

Prototype:	function DeleteFrom( const Where : string) :integer;
Description:	Deletes rows from a table based on the condition specified in Where. Returns number of deleted records. List of deleted records is saved to DeletedRecords.log file.
Syntax:	variable:= Layer.DeleteFrom (Where);
	Part	Description
	variable	A variable declared as an integer
	Layer	A reference to the Field-Map layer as defined in Field-Map Project Manager
	Where	The WHERE clause specifies which record(s) should be deleted.
Return value:	Number of deleted records

Example:

var 
  i:integer;    
begin
 
  Trees.Update('SpeciesCategory=100','Species<50');
  
  i:= Trees.DeleteFrom('DBH_mm>900');
  ShowInformation(format('Number of deleted records: %d',[i])); 
  
end.

See also:

Value; ValueAsString; ValueAsinteger; ValueAsFloat; ValueAsboolean; OldValue; PreviousValue; BOF; EOF; RecordCount; State; SetValues; SetValuesFromXML; CrownProjection; CrownProfile; CrownProfilePoints; StemProfile; OldLayer; SavePosition; RestorePosition; SaveState; RestoreState; SavePositionAndState; RestorePositionAndState; Open; Close; First; Last; Next; Prior; Edit; Post; Append; Delete; Cancel; Refresh; Locate; ClearTable; Filter; Filtered; CheckFilter; SetFilterExt; ClearFilterForChildLayers; DeepFilter; EnableCachedUpdates; ApplyUpdates; GetAttributeValue; GetQueryResult; DeleteFrom; Update; CreateMemTable; SaveToDBF; SaveToExcel; GetMinOfAttributeValues; GetMaxOfAttributeValues; GetMeanOfAttributeValues; GetSumOfAttributeValues; GetRecordCount; GetLookupTable; GetLookupListValue; GetLookupListAttributeValue; GetID; GetIdAttributeName; GetIdSQL; SaveTimeStamp; File2Blob; Blob2Folder; String2Blob; Blob2String; FillAttributeValues; MarkValuesAsConditional;GetListOfChildLayers; GetPercentageOfFilledAttributes4Record; GetPercentageOfFilledAttributes4Layer; RoundAttributeValues