FdoExpressionEngineImp::Like should return false on mismatched data types

[jng]

I was performance testing some MapGuide feature joins when I encountered a cryptic "Fetching a property value did not match the property type" error.

Some extensive debugging revealed that the error was caused by MapGuide instructing FDO to do a LIKE evaluation against an integer and a string.

In the current implementation of FdoExpressionEngineImp::Like, mismatched data types (ie. left or right arguments are not string property values) will result in an exception being thrown.

Given MapGuide is lenient on what types of properties can be joined, shouldn't the FDO expression engine just return false on mismatched data types instead of throwing an exception? It's clear the LIKE condition in such cases will not evaluate to true, so why not just return false?

[jng]

Proposed patch

[jng]

Fixed r6288