[EpiData-list] relational databases- using a mother file field in a check for a child file field

Dear listers,

I have created a relational EpiData database where the value of a field called RECDATE is automatically passed from the mother file to the related child file. This works fine. I have a field in the child file called DATE and wish to ensure that DATE is always later than RECDATE. I have tried the following check:

date AFTER ENTRY IF DATE< RECDATE THEN HELP "The date can't be earlier than the date of recruitment" TYPE=ERROR ENDIF END END

And I get the following error:

Error in IF expression: Invalid parameters to DATE.

Does anyone have any advice on using automatically passed variables in checks? All help is much appreciated. In case it helps, here is the start of my child.chk file.

BEFORE RECORD RECDATE=varRECDATE END

id KEY 1 END

recdate NOENTER END

date RANGE 1/1/2006 31/12/2007 LEGAL 1/1/1800 1/1/1900 END AFTER ENTRY IF DATE< RECDATE THEN HELP "The date can't be earlier than the date of recruitment" TYPE=ERROR ENDIF END END

Katherine Smith Research Assistant Clinical Epidemiology and Biostatistics Unit (CEBU) Murdoch Childrens Research Institute (03) 9345 7957 katherine.smith@mcri.edu.au