Help with nesting a comparison of two parameters in an Expression

Question

Hi,
As part of the query I am trying to write, I need to compare two dates which are not stored in my database - one specified by the user and the other defined in the code. I have tried using the postfixSQL method, but although this compiles and does not throw an error at runtime, the SQL I specify is not being included in the SQL statement that Toplink generates.
My code is as follows:
Date searchStart; // the opening date / time of the period to search for
Date searchEnd; // the closing date / time of the period to start for
Date limit; // a date / time beyond which results are irrelevant and should not satisfy the query
Date midnight; // date representing midnight
ExpressionBuilder hold = new ExpressionBuilder();
Expression ex1 = hold.get("sunOpen").lessThanEqual(searchEnd);
Expression ex2 = hold.get("sunClose").greaterThanEqual(searchStart);
Expression ex3 = ex1.and(ex2);
Expression ex4 = hold.get("satEnd").lessThan(limit);
Expression ex5 = hold.get("satEnd").greaterThanEqual(searchStart);
Expression ex6 = ex4.and(ex5);
I then want to be able to do something like:
ex6 = ex6.and(midnight <= searchEnd);
Expression finalExpression = ex3.or(ex6);
I am struggling to find a way to create a valid Expression that I can nest as part of a query that will let me compare two objects that aren't stored in the database. Please excuse me if I'm missing something obvious - I'm new to all this!
Thanks in advance for your help.
Brooke

Answer 1

Hello Brooke,
I'm not sure what the SQL you want to generate looks like. From the expression, it looks like this could be more easily done in code:
Expression ex6 = ex4.and(ex5);
Expression finalExpression = ex3;
if (midnight <= searchEnd){
finalExpression = finalExpression.or(ex6);
If you are instead looking how to use constants in the expression framework, check out the value() api. Something like
ex6 = ex6.and(hold.value(midnight <= searchEnd));
or
ex6 = ex6.and(hold.value(midnight).lessThanEqual( searchEnd ));
Best Regards,
Chris Delahunt