[IronPython] [python] Re: Object DBs - Zope/Plone vs LINQ?

[Keith J. Farmer]

I agree, unless Guido decides to put query syntax in CPython.  Thankfully, you don't need to add query syntax to get the benefits of LINQ, if you have the bits in B (especially type inference, implicit typing, and anonymous types).  I'm just as happy writing:
 
q = db.Customers.Where(c => c.City == "London").Select(c => new { c.Name, c.Age })
 
instead of
 
q = from c in Customers where c.City == "London" select new { c.Name, c.Age }
 
provided I don't have to specify generic types everywhere:
 
q = db.Customers.Where<Customer>(c => c.City == "London").Select<Customer, some-unnamable-type>(c => new { c.Name, c.Age })

________________________________

From: users-bounces at lists.ironpython.com on behalf of Michael Foord
Sent: Fri 9/28/2007 4:17 PM
To: Discussion of IronPython
Subject: Re: [IronPython] [python] Re: Object DBs - Zope/Plone vs LINQ?



Keith J. Farmer wrote:
> There are various degrees to which a language can support LINQ, in decreasing sweetness:
> 
> A: adopt new, first-class syntax in the language to easily construct LINQ queries
> B: stop short of syntax, but include the features underlying LINQ: extension methods, expression trees, anonymous types, type inference, implicit typing
> C: allow access to the .NET libraries which implement the operations the LINQ pattern
> 
>  

I think there would be howls of protest from the Python community if the
IP team opted for A - but it would be nice to see some of the B level
features in IronPython. Maybe these could be provided at the DLR level
to support all of the DLR languages?

Michael Foord
http://www.manning.com/foord

> C#3, VB9, and a few others are at the fully-LINQ-enabled "A" level.  They've modified the language to make access to the features listed in B and C transparent
> 
> Unless Dino, Martin, & co have been hiding things from me, IronPython is still at the "C" level.  Because it can access the .NET libraries, a programmer can manually do everything necessary for LINQ:  make calls to the static methods on the new Enumerable and Queryable classes.  Expression trees still need to be constructed manually to make LINQ to SQL work, but it's still doable, and helper methods could make things work a little smoother.  You still get the same effect:  you don't have to know SQL, you don't have to change your query language when you switch databases (TSQL != PL/SQL != MySQL != Matisse).
> 
> Adding just the B-level of features would make IP very, very sweet.
> 
> Incidentally, it should be pointed out for the record that LINQ isn't just databases.  It's really any generalized data store: objects, RDBMS, and XML are just 3 featured applications of the pattern -- there are also web services, LDAP, file systems, etc.  Also, in LINQ to SQL's case certainly, these are full-fledged queries, not simple CRUD:  server-side calculated columns, arbitrary projections, paging operations, etc are translated into actual SQL and sent to the server.
> 
> -- Keith J. Farmer [MSFT: LINQ to SQL]
>
> ________________________________
>
> From: users-bounces at lists.ironpython.com on behalf of Matt Clinton
> Sent: Fri 9/28/2007 3:42 PM
> To: Discussion of IronPython
> Subject: [IronPython] Object DBs - Zope/Plone vs LINQ?
>
>
>
> Folks,
>
> I was recently reading the July issue of Visual Studio mag, and the
> opening few paragraphs of their article on "Layer Data Access..."
> reminded me strongly of the problem solved by Zope/Plone in CPython
> land: databases with linked objects, rather than tabled varchars, bytes,
> etc.
>
> They go on to talk about how LINQ will allow storage/retrieval (CRUD) of
> CLR objects through a SQL-like syntax.
>
> Will IronPython have access to both these approaches?
> If so, there could be very terse & clean crossovers through it.
> Any reflections on when to use which?
>
> Food for thought,
> -- Matt
>
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