LINQ: Building an IQueryable Provider - Part VIII

Techy News Blog » LINQ: Building an IQueryable Provider - Part VIII

Techy News Blog » LINQ: Building an IQueryable Provider - Part VIII — Wed, 10 Oct 2007 01:07:33 GMT

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LINQ: Building an IQueryable Provider - Part VIII

Noticias externas — Wed, 10 Oct 2007 01:14:13 GMT

Implementing OrderBy Today's topic is translating those order-by clauses. Fortunately, there is only

LINQ: Building an IQueryable Provider - Part VIII

Roller — Wed, 10 Oct 2007 02:29:34 GMT

Implementing OrderBy Today's topic is translating those order-by clauses. Fortunately, there is only

re: LINQ: Building an IQueryable Provider - Part VIII

Ron K. — Wed, 10 Oct 2007 17:27:31 GMT

From a perf standpoint, are these two queries the same?

SELECT t0.CustomerID, t0.ContactName, t0.Phone, t0.City, t0.Country

FROM Customers AS t0

ORDER BY t0.Country, t0.City

SELECT t1.CustomerID, t1.ContactName, t1.Phone, t1.City, t1.Country

FROM (

SELECT t0.CustomerID, t0.ContactName, t0.Phone, t0.City, t0.Country

FROM Customers AS t0

) AS t1

ORDER BY t1.Country, t1.City

Thanks.

re: LINQ: Building an IQueryable Provider - Part VIII

mattwar — Wed, 10 Oct 2007 17:59:43 GMT

Yes, they'll build the same query plan on the server, as they are logically the same thing. The only difference is the second one has more text to parse. The server is free to rearrange any query you give it as long as maintains the same semantics. (The results are the same.)

re: LINQ: Building an IQueryable Provider - Part VIII

vadym — Wed, 10 Oct 2007 18:18:15 GMT

Can someone suggest a way of creating a flat query instead of a hierarchical one? So far the query binder walks through an expression tree and adds a new select layer over the previous query.

I tried to create a query flattener that picks up a SelectExpression object and pulls relevant parts of all nested SelectExpressions to the top SelectExpression. So if I had the following query

SELECT t2.ContactName, t2.City, t2.Country

FROM (

SELECT t1.ContactName, t1.City, t1.Country

FROM (

SELECT t0.ContactName, t0.City, t0.Country, t0.CustomerID, t0.Phone

FROM Customers AS t0

) AS t1

) AS t2

WHERE (t2.City = 'London')

I would pull the name of the table from the deepest SelectExpression, the projection clause (the columns to select) from the top-level SelectExpression and so on.

This solution is quite nice in general. By creating another visitor (QueryFlattner calss) that post-processes the output of the QueryBinder, I don’t intervene in binding (Because I believe Matt will keep on posting on LINQ and QueryBinder will change with time. But on the other hand why to create a structure that must always be post processed and not to create the one I need?) Anyways, when it came to the implementation I figured out the lack of consistency in flattening rules. Things got much worse when queries got more complicated (e.g. joining more than 2 entities).

re: LINQ: Building an IQueryable Provider - Part VIII

rogerj — Wed, 10 Oct 2007 22:41:07 GMT

Pingback from http://oakleafblog.blogspot.com/2007/10/linq-and-entity-framework-posts-for_09.html

Community Convergence XXXIII

Charlie Calvert's Community Blog — Mon, 15 Oct 2007 03:55:02 GMT

Welcome to the thirty-third edition of Community Convergence. This week we have a new video called Programming

Community Convergence XXXIII

Charlie Calvert's Community Blog — Mon, 15 Oct 2007 04:17:54 GMT

Welcome to the thirty-third edition of Community Convergence. This week we have a new video called Programming

Community Convergence XXXIII

Charlie Calvert's Community Blog — Mon, 15 Oct 2007 04:25:38 GMT

Welcome to the thirty-third edition of Community Convergence. This week we have a new video called Programming

Community Convergence XXXIII

Charlie Calvert's Community Blog — Mon, 15 Oct 2007 15:02:02 GMT

Welcome to the thirty-third edition of Community Convergence. This week we have a new video called Programming

re: LINQ: Building an IQueryable Provider - Part VIII

hasmukhkp — Tue, 23 Oct 2007 14:20:38 GMT

I was wondering whether this code works for Properties instead of fields.....

Could you guide me for the same?

Thanks

Hasmukh

Developing Linq to LLBLGen Pro, part 10

Community Blogs — Fri, 21 Dec 2007 17:43:22 GMT

(This is part of an on-going series of articles, started here ) Whoa, almost a month without an update

TerraServer Sample: A LINQ Provider

Charlie Calvert's Community Blog — Mon, 07 Jan 2008 04:37:06 GMT

Over the holidays Alex Turner, Mary Deyo and I added a new sample to the downloadable version of the

LINQ: Building an IQueryable Provider - Part IX

The Wayward WebLog — Thu, 17 Jan 2008 06:08:11 GMT

This is the nineth in a series of posts on how to build a LINQ IQueryable provider. If you have not read

Subtree substitution, thanks to microsoft ExpressionVisitor

Alkampfer's Place — Wed, 05 Mar 2008 10:24:35 GMT

Subtree substitution, thanks to microsoft ExpressionVisitor

Developing Linq to LLBLGen Pro, part 10

.Net World — Tue, 15 Apr 2008 00:29:27 GMT

(This is part of an on-going series of articles, started here ) Whoa, almost a month without an update

LINQ: Building an IQueryable Provider - Part X

The Wayward WebLog — Wed, 09 Jul 2008 02:29:27 GMT

This is the tenth in a series of posts on how to build a LINQ IQueryable provider. If you have not read the previous posts you'll want to find a nice shady tree, relax and meditate on why your world is so confused and full of meaningless tasks that it

LINQ: Building an IQueryable Provider - Part XI

The Wayward WebLog — Mon, 14 Jul 2008 22:32:08 GMT

This is the eleventh in a series of posts on how to build a LINQ IQueryable provider. If you have not read the previous posts you’ll want to do so before proceeding, or at least before proceeding to copy the code into your own project and telling your

Building a LINQ IQueryable Provider - Part XII

The Wayward WebLog — Tue, 18 Nov 2008 04:04:45 GMT

This is the twelfth in a series of posts on how to build a LINQ IQueryable provider. If you have not

LINQ links

The Wayward WebLog — Tue, 18 Nov 2008 20:27:13 GMT

Part I - Reusable IQueryable base classes Part II - Where and reusable Expression tree visitor Part II

LINQ: Building an IQueryable provider series

Floating Heart — Thu, 19 Mar 2009 17:51:33 GMT

http://blogs.msdn.com/mattwar/pages/linq-links.aspx Here's a list of all the posts in the building