incremental load issue in SSIS

Hi All,

i am trying to do incremental load in SSIS and automatically it is changing to full load.

i have created three variable one is incLoad,IncLoadDate and SQL.

in the IncLoad varibale i have assigned to "Y".

INCLoadDate i have wrote this expression - @[Config::IncLoad]  =="Y" ?   DATEADD( "DAY",-1, (DT_DBDATE) GETDATE() ): (DT_DBDATE)   "1/1/1900" 

means if it is equl to "Y" perform full load and if it is "N" perform greater than equal to yesterday data.

for the SQL varibale i have assigned this expression  - "Select * from sample where Start_DATE >=TO_DATE(" +"'"+(DT_WSTR,50) @[Dev::IncLoadDate]+ "'" +",'MM/DD/YYYY')".

and i have used this SQL variable in data Access mode as command line from variable.

when i am changing to IncLoad variable to "N",it is showing yesterday date,but while running the package it is doing full load.its changing automatically to full load.

can anybody help me here why it is changing to full load.

Thanks,