JohnPapa.net

Entity Framework and LINQ Presentation

Wednesday, May 21 2008 - entity-framework, ado-net, linq, ineta - 0 comments

I had a great time at the INETA sponsored combined Sarasota SQL Server and Sarasota .NET User groups' meeting last Wednesday evening. I presented the Entity Framework and LINQ using the latest bits, which came out 2 days prior to the presentation. It made for some interesting moments as I barely had enough time to convert all of my demos over to the latest bits. Yeah, I know, I should have just went with the old bits, but the smart me was sleeping and the bold me took the wheel :)

I've attached my slide deck and some demo code that I used for the presentation. The code has been converted to work with the Visual Studio and .NET 3.5 SP 1 beta bits. Everything is "as is" as some of the demo code I wrote on the fly at the presentation.

There were about 40 people there for the presentation and it was a very lively and interactive group. A lot of good questions were posed and thought he flow was pretty fast it seemed to be well received.

Need a "WHERE field IN (x, y, z)" Clause with LINQ

Tuesday, May 20 2008 - sql, linq - 2 comments

A colleague and I were talking about some LINQ features yesterday and one of the topics that came up was how to implement an IN clause. Ya know, similar to how SQL statements can use an IN clause in the WHERE clause like this:

SELECT city FROM Customers WHERE state IN ('FL', 'NY'', 'NC')

Then I remembered Dan Wahlin's post on a similar topic where he shows the following solution (from Dan's post):

The code uses the Contains() method to search for a specific ProductID within the collection which ends up creating a WHERE IN type query.  You can do the same thing with LINQ:

public static Product[] GetProducts(Guid[] prodIDs)
{
   return (from p in GetProducts()
           where prodIDs.Contains(p.ProductID)
           select p).ToArray<Product>();
}

The idea here is that the LINQ query is written normally (meaning the from and the select clauses reference the objects). Then the where clause in the LINQ query operates on an array of values. The array of values contains the values you would put in the IN clause. The array supports standard query operators so you can use the Contains method on the array and pass in the value you want to look for.

Entity Framework & LINQ in Miramar, FL

Monday, May 19 2008 - entity-framework, linq - 0 comments

I'll be heading to Miramar, FL on July 8th for the local .NET User Group meeting to speak to the group about the Entity Framework and LINQ. I "hope" the final bits are released by then, but not on July 8th, please (yikes!). I went through a major overhaul of my demonstrations last week when the latest beta bits were released and it was the day before my last presentation on LINQ and the Entity Framework. It went well, but it was a bit too much "last minute" for me. Especially when I am spending every free moment writing my Silverlight book and its examples.

There is a lot to demonstrate .... showing why it exists, how it works, how to use it with a real world application. There are also the discussions of where it is heading, when to use it, when not to use it, and how it compares to existing tools. I often get asked "should I use EF in my app?". The answer always depends of course. But I generally do not encourage people to rip out their existing architecture and replace it with anything unless there is a major benefit that you can receive. The EF is a great tool, no doubt, but it still does not support certain aspects that would make it great (i.e. POCO). Can EF be everything to everyone? No, certainly not. Can EF be a valuable piece of your architecture? Absolutely. Would I jump up and down continuously for a week if they made it work with POCO?  HECK YES!

Anyway ... its a good topic and always stirs up a good discussion, which is why I love talking about it. Its not about the model and its not about the data. Its about both, together.

If you are going to be in the area, please stop by. Should be a good discussion in South Florida! Here is the registration link.

Silverlight Consuming REST Services

Friday, May 16 2008 - silverlight, rest, linq, xml, wcf, book - 3 comments

I just finished writing the first draft of a sample I am including in my upcoming book tentatively titled Data Access with Silverlight 2 by O'Reilly. Without giving too much away yet since the final details of the contract are not set in stone, the application example consumes a REST service, manipulates it through LINQ to XML, and binds it to various controls and some composite controls. The interaction with the REST (REpresentational State Transfer) services is pretty slick and quite easy when using Silverlight and LINQ to XML. Of course there are always issues to deal with, but overall it works very nicely.

Why use REST? Well, REST services are becoming more abundant on the web. They do not expose a contract like WCF so when you deal with this type of data you can parse the XML using LINQ to XML or some other XML tools (though LINQ TO XML is so smooth why bother with anything else in this case). So this raw XML comes barreling into your Silverlight application asynchronously, LINQ to XML makes it fall in line, and its bound to where it needs to go via XAML.

Sending data back via REST is also very cool. I've got that working now too. I have to be careful not to go overboard fine tuning the examples though or the book will never get written :) Interacting with REST from Silverlight applications is just one piece of the data access puzzle, but its pretty cool.

Visual Studio 2008 and .NET 3.5 SP 1 Beta Download

Monday, May 12 2008 - visual-studio, net, entity-framework, linq, sql-server, astoria - 1 comments

Soma announced this morning that Visual Studio 2008 and .NET 3.5 SP 1 is now ready and can be downloaded. This includes several updates, includes support for SQL Server 2008, and has a few new products including the Entity Framework, LINQ to Entities and ADO.NET Data Services (aka Astoria). ScottGu posted some notes regarding what's included in the service pack, as well.

Of course all of this is released 2 days before I have a demonstration on the Entity Framework and LINQ to Entities on Wednesday to the Sarasota .NET and SQL Server User groups. So I have a few modifications to make for my presentations.

I received an error when I first tried to install it. The problem was that the service pack was in conflict with Silverlight Tools Beta for Visual Studio 2008 which I was using to create/edit Silverlight 2 applications. Once uninstalling this i was able to get the service pack to install properly. Scott Gu's post discusses this issue as well as the importance of making sure you install Vista SP 1 first.

Check out ScottGu's post for full details.

Silverlight, WCF and LINQ to SQL

Wednesday, May 07 2008 - silverlight, entity-framework, linq, sql, wcf - 1 comments

I've had some requests lately to write some articles that work with LINQ to SQL. I've ben focusing on the Entity Framework a lot due to its vast nature and that fact that its still relatively unknown to many people. So I am going to work on a LINQ to SQL project that ties into a multi tier model. I am also going to show how this can be hooked into a  Silverlight 2 UI that connects through WCF to the lower layers.

I'll probably be demonstrating these first at an event I am trying to set up with Joe Healy of Microsoft in Tampa this coming August. The demos will be ready way before then, but I wanted to have some cool materials for this event. There is no title nor date yet, but once the event is set I will be sure to let blog about it. It should be a great day overall.

I also plan on giving some love to the Entity Framework, regular persistence/mapper models, MVP patterns and more. I just have to find a way to work it all in and still give enough to each topic. Of course, this means all demos are subject to change, but the content will be fresh and cool for certain.

Here is a very poorly and quickly thrown together diagram of one of the demos I am tweaking.

Entity Framework Q&A - Lazy Loading, ObjectContext, and LINQ

Monday, May 05 2008 - data-points, linq, entity-framework - 0 comments

I've received hundreds of questions regarding the Entity Framework and LINQ. Obviously developers are very interested in the Entity Framework and its data access and modeling implications. 

I responded to some of the most frequently asked questions in the May 2008 Data Points column. Topic includes:

• Why use Entity SQL when I can use LINQ to get to entities?
• What is the role of ObjectContext?
• How do explicit and eager loading work LINQ and the Entity Framework?
• How do I see the SQL that will execute?
• What can I do with complex types?
• How do I create a complex type?

You can find my Data Points column in the May 2008 MSDN Magazine issue online.

Projecting with Aggregates in LINQ to Entities

Monday, April 28 2008 - linq, entity-framework, lambda - 1 comments

I'm all for quick and easy examples especially when it comes to LINQ, so here goes one that I get asked a lot. This is a quick example that shows how to grab a few properties from a parent entity and use an aggregate function on the parent entity's children entities. Specifically, this example grabs the OrderID and OrderDate from the Orders entity and then calculates the order total for each order. The sum is calculated by summing the UnitPrice * Quantity in the OrderDetails entity.

// Code below creates a projection containing LCD

var qry = from o in context.Orders

        where o.Customers.CustomerID == customerID

        group o by o.OrderID into g

        join o2 in context.Orders on g.Key equals o2.OrderID

        select new

        {

            OrderID = g.Key,

            o2.OrderDate,

            OrderTotal = o2.OrderDetails.Sum(d => d.UnitPrice * d.Quantity)

        };

foreach (var orderInfo in qry)

{

    var msg = string.Format("OrderID={0}, OrderDate={1:d}, OrderTotal={2}",

                orderInfo.OrderID, orderInfo.OrderDate, orderInfo.OrderTotal);

    Console.WriteLine(msg);

}

Notice the grouping of the orders first. Then the Orders are joined back to the result so we can get the OrderDate property. Then the projection pulls out the Key (the OrderID), the OrderDate, and calculates the OrderTotal using an aggregate and a lambda expression.

Hopefully this will shed some light on this type of projection with LINQ for some.

JohnPapa.NET is Open for BusinRSS

Saturday, April 19 2008 - codebetter, graffiti, devconnections, entity-framework, ssrs, sql-server, linq - 0 comments

No that's not a typo in the title ... it's my poor attempt at dry humor :)

I have had several questions from people over the past few months regarding my noticeable sparseness in blogging at www.codebetter.com, my blogging home for the past 3 years. The truth is that it took me a while to get back to setting up my new blogging home at www.johnpapa.net . I used the various beta versions of Graffiti CMS to get it started and then I recently migrated the site over to the release version of Graffiti. I must say that Graffiti is perfect for my needs. I can consolidate my posts, organize my events, articles, and add some ASP.NET and SilverLight aspects, too.

So what will you find on www.johnpapa.net ? You will find my usual technical posts as well as a listing of all of the articles I have published (the books listing is not there yet) and all of the events I will be speaking at as they get scheduled and confirmed.

Will I still post to www.CodeBetter.com ? Yes, I will still cross post some content to www.CodeBetter.com but the superset of the posts will be on www.johnpapa.net including technical content, reviews, and opinions.

So please add my new site www.johnpapa.net to your aggregated feed  list http://feeds.feedburner.com/JohnPapa.

I'll be at DevConnections this coming week in Orlando, so if you are going to be around please stop by one of my sessions on windows mobile development, LINQ, the Entity Framework or SQL Server Reporting Services and say hi!

Standard Query Operators with LINQ

Friday, April 04 2008 - entity-framework, linq, data-points, msdn - 0 comments

In the March issue of MSDN Magazine's Data Points column I explore a variety of the Standard Query Operators and how they work with LINQ. Here is a summary of the article:

In this month's column I will perform practical queries and operations with LINQ, using both LINQ to Objects and LINQ to Entities. I'll query a single collection of entities and dive deeper into a hierarchical set of entities using their navigation properties. I'll also show how you can apply many of the standard query operators to arrays and collections. I will demonstrate how LINQ's standard query operators are enhanced using lambda expressions and how they can let you parse specific information from a sequence and perform complex logic over a sequence.

You can check it out here.

Designing an Entity Data Model

Sunday, January 20 2008 - entity-framework, linq, data-points, edm - 0 comments

Just published is my article on Designing an Entity Data Model with the Entity Framework tools. This article is part of my Data Points column in the February issue of MSDN Magazine. A few months ago I wrote an article discussing an overview of the Entity Framework and examining the CSDL, SSDL, and MSL that defines the EDM. When that article was published the tools were not available, so in this article I  decided to explain how the tools work which coincides nicely with the previous article's explanation of the XML files (CSDL, SSDL, MSL). The EDM designer sits  on top of the XML files and uses the XML information to represent the model. Likewise, the model can be changed using the designer tools which then updates the XML under the covers.

I will be having a few more articles in the upcoming months that explain more about the Entity Framework and its auxiliary parts. For next month's issue I plan on going through many of the Standard Query Operators that can be used with LINQ to objects/entities. Also, if you are planning on attending DevConnections in Orlando in the Spring (this April), I will be presenting 2 different 1:15 minute sessions on the Entity Framework there as well.

As always, if you want to review my history of articles, please visit my articles history page where you can find them all listed.

New EF CTP! ADO.NET Entity Framework June 2007 CTP is Available

Friday, February 01 2008 - net, ado-net, entity-framework, linq - 4 comments

The ADO.NET team has released the latest bits for the ADO.NET Entity Framework with the June 2007 CTP. There are samples on CodePlex, too. It claims many changes and support for a lot of new features ... I grabbed this partial list from their post:

• Changes in: 
• Object Services
• Query
• Entity Client
• the Entity Data Model Wizard in Visual Studio 
• no more default constructors in code-generated classes
• improvements to stored procedure support

• New Features:
• IPOCO
• detaching from long-running ObjectContext instances
• multiple entity sets per type
• support for referential integrity constraints
• span support
• transactions
• serialization

Notice the IPOCO support. This is something that is a step in the right direction for getting the entities in the EDM to move towards full POCO. I am downloading the bits now and can't wait to unwrap the candy!

Data Access "Practically Done"

Friday, February 01 2008 - net, ado-net, entity-framework, linq, ent-lib, sql - 3 comments

I will be kicking off my move to South Florida in a few weeks with a 1 day event for the “Practically Done” event series. On Wednesday August 1^st and on Saturday August 4^th I will be presenting “Data Access Done Right”, a full day event in Orlando.

Register here for Wednesday, August 1^st – 9am to 5pm

Entity Framework and its Tools in First Half of 2008

Friday, February 01 2008 - ado-net, entity-framework, linq - 2 comments

As I noted earlier, my latest article in MSDN Magazine was just posted a few days ago. If you visited it early on you might have missed the comment from the edtitor which reads:

[ Editor's Update - 6/19/2007: The ADO.NET Entity Framework and Tools will ship during the first half of 2008 as an update to the Visual Studio 2008 release.]

We were told the tools would ship later, so this just confirms the plans for the EF and its tools to be available next year. I'll be chomping at the bit to use it and giving as much feedback as I can to the team as I can. They seem dedicated to making a great product that we can use in DDD.

ADO.NET Entity Framework Overview

Friday, February 01 2008 - net, ado-net, entity-framework, linq - 0 comments

My July 2007 Data Points column has been posted to the MSDN Magazine web site. This edition is titled "ADO.NET Entity Framework Overview".

I wrote this using the March CTP and then revised it using the Orcas Beta 1, so the code included works in the most recently available bits. Knowing that changes are on their way, I tried to focus the article on the concepts and technical aspects of the EF that make ups its foundation. The components such as Object Services, Entity Client, and LINQ to Entities will evolve but are fairly well baked. Aspects I expect to change (although I have no evidence to support it) are the way the entities are implemented. For example, I expect they may evolve into more of a POCO style with no interface nor base class required. This topic has been beaten pretty hard, so I won't add anything further to it for now since I agree with most of what has already been blogged about. There is one piece which I know is on its way, however late to the game it may be ... the EDM Designer. 

Anyway ... this article is an overview of how the EF is structured and how its pieces work. I inlcuded some examples as well. It was difficult to keep the word count down on this one ... my first draft had over 7000 words in it (supposed to be about 3000). So we cut it down to a reasonable and digestable size. I hope you enjoy it!

Entity Framework: CSDL, MSL and SSDL Schemas

Friday, February 01 2008 - net, ado-net, entity-framework, linq - 0 comments

Due to the lack of a designer and because I am very curious, I’ve been digging through the XML for the CSDL, MSL and a little bit into the SSDL schemas for the Entity Framework’s Entity Data Model. Even if you are waiting for the Designer to be released (date TBD) it cannot hurt to get familiar with these XML file structures. For example, the MSDL’s schema supports the following for the mapping Conditions:

<!-- Type for Condition Element-->

  <xs:complexType name="TCondition">

    <xs:attribute ref="tns:Value" use="optional" />

    <xs:attribute ref="tns:Name" use="optional" />

    <xs:attribute ref="tns:ColumnName" use="optional" />

    <xs:attribute ref="tns:IsNull" use="optional" />

  </xs:complexType>

Currently the conditions in mapping only allow you to compare a column to a scalar value or to check for NULL. You can create multiple conditions, which will create an AND situation. However you cannot combine the conditions with OR’s (i.e. you can’t say get all orders > $10,000 or  orders < $100).  In fact, nor can you compare values at this point (i.e. < ). These features are surely going to be in future versions, though.

By having the XSD’s for the CSDL, MSL AND SSDL you can explore what options are available even if the intellisense is not working in the latest CTP J (which has happened to me at times). For example, I noticed that complex properties are in the schema, however they are not fully supported at this time. But at least this gives me a glimpse at what might be supported in the future.

I open the XSD’s in Visual Studio.NET Orcas, but of course you can use other tools like XML Spy. Here is a snapshot of the TableMappingFragment’s schema from the MSL file:

If you are looking for the XSD’s, you can find them in the March Orcas CTP located at this folder:

C:\Program Files\Microsoft Visual Studio 9.0\Xml\Schemas

And the file names are:

-          CSDLSchema.xsd

-          CSMSL.xsd

-          SSDLSchema.xsd

Entity Framework Thoughts

Friday, February 01 2008 - net, ado-net, entity-framework, linq - 13 comments

Stored Procedures and CUD (minus the R) in the Entity Framework

Friday, February 01 2008 - net, ado-net, entity-framework, linq - 0 comments

The Data Access Team published a great post that has some superb explanations on how to make the Entity Framework use stored procedures for inserts, udpates and deletes. (It does not yet support stored procedures for retrieving data.)   Obviously there are pieces missing, as Shyam states (such as retrieving data via sprocs), but to see CUD (minus the R) working in the EF with sprocs is great.

One knock I can already hear though is how people will have to change the existing sprocs. Specifically in the example where the additional parameter must be added to support the EF's  determination of which entities/sprocs to execute in which order. Obviously it would be better if a future evolution could do without this.

Fantastic to see sproc support born in the Entity Framework!

On a related note, I am having a heck of a time trying to get an overview of ADO.NET Orcas to fit into a publishable article. There is just sooooo much to it and so little space to write about it. I could go on for days on this topic :)

LINQ to Entity Samples added to 101 Samples!

Friday, February 01 2008 - net, ado-net, entity-framework, linq - 1 comments

Earlier in March I posted that some samples intended for use with the March CTP of Orcas were available for download. These samples replace the samples that are linked from the MSDN docs in the CTP. One thing these samples lacked was the LINQ to Entities samples. Today, Charlie Calvert posted a link to updated samples that include LINQ TO Entities samples inside the SamplesQueries example project. Inside the SamplesQueries project you will find a 101 LINQ to Entities samples.

This is great news! Previously there were tons of examples in this project for LINQ to SQL, LINQ to XML, LINQ to Objects and LINQ to DataSets. With the additin of LINQ to Entities, it means I have plenty of material to play with and keep my head buried in ADO.NET and the Entity Framework.

You can download the new samples here.

Entity Framework and Object Services Primer

Friday, February 01 2008 - net, ado-net, entity-framework, linq - 0 comments

As I am sure you have read by now, the Entity Framework is a huge leap forward in the next iteration of ADO.NET in Orcas.  Currently the implementation has a conceptual layer represented by a CSDL file. This CSDL file contains the XML that represents conceptual model (the objects). The conceptual layer is mapped to the database through a series of lower layers (the Mapping and the Source). The Source is represented by a SSDL file which contains XML that represents the database schema. The MSL file contains the XML that maps the CSDL to the SSDL. All 3 of these files can be generated using the EDM Model Wizard in the Orcas Feb/March CTP.

Once the model has been generated (or created by hand), the data can be manipulated and interrogated through the conceptual model. Thus a level of abstraction is created where an application can interact with data through an object model that is mapped to the underlying data source. LINQ to Entities or Entity SQL can be used to interact with the EDM. LINQ to Entities is great when you can define your query expressions at design time and enhance them with parameters. Entity SQL can also be sued to achieve the same goals, however since Entity SQL is string based it can support more dynamic queries where queries can be built on the fly.

There is quite a bit to chew with the Entity Framework, more than enough for a entire series of articles. And I have not even touched on the other ADO.NET components such as LINQ to SQL or LINQ to DataSets, much less the designers, LINQ to objects, LINQ to XML, EntityClient and much much more.

It is an exciting time to be involved with data access technologies! And some unforeseen changes are yet to come as many have already experienced the changes through the CTP’s of LINQ and Orcas. But it seems evident that the data access team is making its biggest change to data access in a very long time.

Updated Samples for Orcas March 2007 CTP

Friday, February 01 2008 - net, ado-net, entity-framework, linq - 0 comments

Charlie Calvert has posted some samples intended for use with the March CTP of Orcas. These samples replace the samples that are linked from the MSDN docs in the CTP (which is good since I have had mixed result wth them so far). Charlie also posted a video on the samples here that helps explain them.

Entity Framework Terminology

Friday, February 01 2008 - net, ado-net, entity-framework, linq - 0 comments

I have some articles to write on the Entity Framework and LINQ to ADO.NET, so I will be busy in the depths of EF for a while. I have been spending the past few days immersing myself in the Orcas March CTP. While there are features I am still longing for (such as the EDM Designer) this is the most EF & LINQ complete CTP in a long time. While the MSDN Documentation is not complete by any means, there is some great information in there. For example, I found this fantastic page in the help docs that is a glossary of the Entity Framework terminology. I pulled this directly from their documentation, which you can find at this link (ms-help://MS.MSDNQTR.v90.en/MS.MSDN.v90/MS.VisualStudio.v90.en/WD_ADONET/html/fa2a1bd1-6118-487b-8673-eebc66b92945.htm ) in the March CTP's help docs. This is a great reference to lean on when learning the EF ... kudos to the data team for creating and including this information in the CTP.

Entity Framework terminology:

alias

 An attribute of the Schema element in CSDL and SSDL schemas that can be substituted for the full namespace to shorten element references in the schema.

association

 The definition of a relationship between entity types.

association set

 A logical container for instances of associations of the same type.

base type

 A parent type or super-type in the EDM from which derived types inherit some of their properties.

complex type

 An entity type whose properties have internal properties. Used as a property of an entity type or of another complex type.

conceptual schema definition language (CSDL)

 XML-based dialect used to define the entity types, associations, entity containers, entity sets, and association sets of a conceptual model.

conceptual model

 Abstract specification for the entity types, associations, entity containers, entity sets, and association sets comprising an application domain.

constraint

 Restricts the possible values of a property and ensures that a value is valid.

container

 A logical grouping of entity and association sets.

degree

 The number of entity types in a relationship. Relationships are classified as unary, binary, ternary, or n-ary.

direction

 Refers to the asymmetrical nature of some associations. Direction is specified with FromRole and ToRole attributes of ReferentialConstraint elements in entity data models.

end

 A participating entity in an association.

entity

 An instance of an entity type.

EntityClient

 A storage-independent ADO.NET data provider containing classes such as EntityConnection, EntityCommand, and EntityDataReader. Works with Entity SQL and connects to storage specific ADO.NET Data Providers, such as SqlClient.

entity container

 Specifies the sets of entity types and associations that will be available in a specified namespace.

Entity Data Model (EDM)

 A system for defining application data as sets of entities and relationships.

Entity Framework

 A set of technologies that supports development of data-oriented software applications by allowing developers to work with conceptual models that are mapped to logical schemas in data sources.

entity-relationship model

 A data model that uses relationships between entities as the basis for describing application data schemas.

entity set

 A logical container for entities of the same type, mapped to tables in a database.

Entity SQL

 A storage-independent dialect of SQL that works directly with conceptual entity schemas and that supports entity data model features such as inheritance and relationships.

entity type

 A named set of properties representing a top-level item in a data model.

enumeration

 A simple type whose single value is selected from a specified set of options.

facet

 A constraint, such as Nullable, MaxLength, or Precision, that limits the allowable values for a property.

helper method

 User-defined operations implemented in partial classes that add functionality to objects generated from entity data models.

key

 The attribute of an entity type that specifies which property or set of properties is used to identify unique instances of the entity type.

language integrated query (LINQ)

 A query syntax that defines a set of query operators that allow traversal, filter, and projection operations to be expressed in a direct, declarative way in C# and Visual Basic.

LINQ to Entities

 The use of language integrated query operators with objects representing a conceptual model.

mapping

 A set of correspondences between items in a conceptual model and items in a storage model.

mapping specification language (MSL)

 An XML-based dialect used to map items defined in a conceptual model to items in a storage model.

metadata

 Data used to describe the structure of other data, including the SSDL XML file, which describes the structure of data in a data store.

Metadata Workspace

 A class that represents the metadata runtime service component that provides support for retrieving metadata.

multiplicity

 The number of entities that can exist on each side of a relationship.

navigation property

 A property of entity types that uses an association to reference related entities.

object services

 Services provided by the Entity Framework to classes generated from a set of metadata.

object context

 A base class that provides object services such as tracking and saving changes, and that contains a connection to the underlying data store.

referential constraint

 An element of an SSDL entity data model that specifies the direction of an association with FromRole and ToRole attributes. Corresponds to a CSDL navigation property.

relational model

 The logical model used to define the tables, columns, and constraints in a database.

relationship

 A logical connection between entities.

role

 The name given to each end of an association to clarify the semantics of the relationship.

simple type

 Primitive type used for defining properties in entity data models.

store schema definition language (SSDL)

 XML-based dialect used to define the entity types, associations, entity containers, entity sets, and association sets of a storage model, often corresponding to a database schema.

table-per hierarchy (TPH)

 A method of modeling a type hierarchy in a database that includes the attributes of all the types in the hierarchy in one table.

table-per-type (TPT)

 A method of modeling a type hierarchy in a database that uses multiple tables with one-to-one relationships to model the various types.

XML (simple type)

 Can contain well-formed XML or valid XML data. The facets of this type control which kind of XML data can be contained within it.

Entity SQL & the EntityClient Provider in ADO.NET vNext and Orcas

Friday, February 01 2008 - net, sql, ado-net, entity-framework, linq - 0 comments

Interesting Orcas & LINQ Links

Friday, February 01 2008 - net, ado-net, entity-framework, linq - 3 comments

LINQ 101 - Which Flavor?

Friday, February 01 2008 - net, entity-framework, linq - 0 comments