What is a type error?

[Chris Smith]

Marshall <marshall.spight at gmail.com> wrote:
> We seem to have slipped back from the hypothetical relation language
> with only assignement back to SQL.

I missed the point where we started discussing such a language.  I 
suspect it was while some of us were still operating under the 
misconception that you assignment to attributes of tuples, rather than 
to entire relations.

I don't see how such a language (limited to assignment of entire 
relations) is particularly helpful to consider.  If the relations are to 
be considered opaque, then there's clearly no aliasing going on.  
However, such a language doesn't seem to solve any actual problems.  It 
appears to be nothing other than a toy language, with a fixed finite set 
of variables having only value semantics, no scope, etc.  I assume that 
relational databases will have the equivalent of SQL's update statement; 
and if that's not the case, then I would need someone to explain how to 
accomplish the same goals in the new relational language; i.e. it would 
need some way of expressing transformations of relations, not just 
complete replacement of them with new relations that are assumed to 
appear out of thin air.

-- 
Chris Smith - Lead Software Developer / Technical Trainer
MindIQ Corporation