Is anyone using SQLString directly?

[Warren Young]

SQLString exists for those places where the library wants to let you 
pass any typical C/C++ type, which it will convert automatically to a 
SQL-compatible string representation.  This is what lets you pass, say,
a mysqlpp::DateTime() to Query::store() to fill in a template query.

MySQL++ currently also provides ColData, which is almost a perfect 
inverse: it takes query results in SQL string form, and lets you convert 
that easily to typical C/C++ data types.

Do we really need two specialized string types in MySQL++?

The only thing that prevents these two from being complete inverses is 
that ColData is purely a constant string, while SQLString derives from 
std::string.  SQLString is potentially useful as a general purpose 
string type, while ColData only accepts new values through its ctors and 
assignment operators.

MySQL++ doesn't need SQLString to be mutable, though, so the only way 
this matters is if someone out there is using SQLString in place of 
std::string.  Unless that's happening, I can combine these two without 
reimplementing std::string or deriving from it.  In fact, it would be an 
almost trivial extension of the current implementation of ColData in svn.

I don't see why anyone would care to use SQLString this way, but I've 
been surprised before...