1.7.31 CQL: Removing null comparisions

Use the ignore_if_null wrapper in your CQL to’filter out' null input values. This is a useful extension for creating user-designed searches.

{[],
 se_lt_x :: [a-UserName,
             b-ignore_if_null(SearchKey),
             ...]}

At runtime, if SearchKey is bound to a value other than {null} then the query will contain WHERE ... b = ?. If, however, SearchKey is bound to {null}, then this comparison will be omitted.

Disjunctions

In general, don't use ignore_if_null in disjunctions. Consider this query:

SearchKey = '%ELSTON%',
{[],
 se_lt_x :: [a-UserName,
             b-RealName],
 ( RealName =~ SearchKey
 ; UserName =~ SearchKey)}

The query means "find a user where the UserName contains ELSTON OR the RealName contain ELSTON". If !SearchKey is {null} then RealName=~ {null} will fail, which is correct. If ignore_if_null was used, the test would succeed, which means the disjunction would always succeed i.e. the query would contain no restriction, which is clearly not the intended result. FIXME: Mike, what is this all about?