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
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