[DB-SIG] Table Oriented Programming

[M.-A. Lemburg]

Brad Clements wrote:
> On 12 Feb 2004 at 13:10, Michael Hobbs wrote:
> 
> 
>>Consider this example code:
>>  departments = DepartmentTable
>>  employees = EmployeeTable
>>  johnsDepartment = (departments * employees) / 
>>    (employees.dept == departments.dept) /
>>    (employees.name == 'John') %
>>    departments.name
>>  print johnsDepartment[0].name
> 
> 
> Has  anyone tried expressing sql operations as relational algebra statements in Python, 
> like the example above.
> 
> I see lots of talk in google, but no code.
> 
> Is this idea out of fashion already? I can see lots of performance issues.. but it's still 
> interesting to me.

FWIW, SQLObject has some logic in place which mimics some of these
ideas.

In general, I think you could work out a "compiler" which generates
SQL from the expression - you'd only need to define a set of special
objects that build a logical representation of the expression by
using the various hooks (__add__, __sub__, etc.).

I don't see any big performance issues, BTW, since you're basically
writing SQL in a slightly different way.

-- 
Marc-Andre Lemburg
eGenix.com

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