Query rule substitute

Question

Hi, 
 
 As you know Query Rule has been deprecated in newer versions of Appian. I need a function that will mimic the exact behaviour of Query rule including the return type. 
 I have tried using queryEntity() but the return type is not the same as query rule so i am facing a lot of issues. 
 
 Please help! 
 TIA

ManuelHTG · Answer

Hello, 
 See documentation 
 https://docs.appian.com/suite/help/20.2/Query_Recipes.html 
 
 If you want to return the same data type, then you need to add as well the cast() function.

Mike Schmitt · Answer

Keep in mind also that traditional query rules will pass back a "dataSubset" type whenever pagingInfo is passed in. 
 Given this, I've previously set up a standard QE recipe which I usually make a new version of for each CDT i might be querying. In that QE expression rule, I run the query entity as normal (using the passed-in pagingInfo if it was given, and a generic set otherwise); then I return the whole dataSubset if the pagingInfo was provided, and return just the ".data" result from the query entity otherwise. 
 Note that this does return basically an "any type" dictionary instead of a type-cast CDT. I've almost never had an issue with this - it does mean that a very few things need to be manually typecast when these are used. You could take the subsequent step of typecasting your ".data" output as the CDT type, but this creates its own issues (such as, if the QE returns a selected set of columns instead of all columns). 
 What exactly is your use case for needing the exact return type? What issues is this causing?

Dave Lewis · Answer

It sounds like you're saving your query result into a local variable. Local variables take on the datatype of whatever they contain. So I think typeof() of your local variable would return "Dictionary". In that case, I wouldn't try wrapping the query entity expression rule in a cast() function, but I would try wrapping the call to that query entity rule in a cast() right there in your local! definition. typeof() might be a good test to run first to make sure that part is working. 
 What's possibly occurring is you sometimes return a null for a particular column, and so when Appian is building a Dictionary in particular, it saves space by not saving the null. Either that or it's the fact that for Dictionary to work it requires both key AND value. None of the Dictionaries in your list of them need to have identical sets of keys. But if you cast it as a list of CDT, they all DO have to have the same keys.

Mike Schmitt · Answer

apoorvam said: Cannot index property 'ABC' into type Dictionary 
 This is a standard error message when you're trying to access a property that doesn't exist - usually if you have the column name wrong, or if your query has resulted in zero rows.