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• Entity Framework 4.0: Optimal and horrible SQL

  - by DigiMortal

  Lately I had Entity Framework 4.0 session where I introduced new features of Entity Framework. During session I found out with audience how Entity Framework 4.0 can generate optimized SQL. After session I also showed guys one horrible example about how awful SQL can be generated by Entity Framework. In this posting I will cover both examples. Optimal SQL Before going to code take a look at following model. There is class called Event and I will use this class in my query. Here is the LINQ To Entities query that uses small anonymous type. var query = from e in _context.Events             select new { Id = e.Id, Title = e.Title }; Debug.WriteLine(((ObjectQuery)query).ToTraceString()); Running this code gives us the following SQL. SELECT      [Extent1].[event_id] AS [event_id],      [Extent1].[title] AS [title]  FROM [dbo].[events] AS [Extent1] This is really small – no additional fields in SELECT clause. Nice, isn’t it? Horrible SQL Ayende Rahien blog shows us darker side of Entiry Framework 4.0 queries. You can find comparison betwenn NHibernate, LINQ To SQL and LINQ To Entities from posting What happens behind the scenes: NHibernate, Linq to SQL, Entity Framework scenario analysis. In this posting I will show you the resulting query and let you think how much better it can be done. Well, it is not something we want to see running in our servers. I hope that EF team improves generated SQL to acceptable level before Visual Studio 2010 is released. There is also morale of this example: you should always check out the queries that O/R-mapper generates. Behind the curtains it may silently generate queries that perform badly and in this case you need to optimize you data querying strategy. Conclusion Entity Framework 4.0 is new product with a lot of new features and it is clear that not everything is 100% super in its first release. But it still great step forward and I hope that on 12.04.2010 we have new promising O/R-mapper available to use in our projects. If you want to read more about Entity Framework 4.0 and Visual Studio 2010 then please feel free to follow this link to list of my Visual Studio 2010 and .NET Framework 4.0 postings.

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• Design pattern for an ASP.NET project using Entity Framework

  - by MPelletier

  I'm building a website in ASP.NET (Web Forms) on top of an engine with business rules (which basically resides in a separate DLL), connected to a database mapped with Entity Framework (in a 3rd, separate project). I designed the Engine first, which has an Entity Framework context, and then went on to work on the website, which presents various reports. I believe I made a terrible design mistake in that the website has its own context (which sounded normal at first). I present this mockup of the engine and a report page's code behind: Engine (in separate DLL): public Engine { DatabaseEntities _engineContext; public Engine() { // Connection string and procedure managed in DB layer _engineContext = DatabaseEntities.Connect(); } public ChangeSomeEntity(SomeEntity someEntity, int newValue) { //Suppose there's some validation too, non trivial stuff SomeEntity.Value = newValue; _engineContext.SaveChanges(); } } And report: public partial class MyReport : Page { Engine _engine; DatabaseEntities _webpageContext; public MyReport() { _engine = new Engine(); _databaseContext = DatabaseEntities.Connect(); } public void ChangeSomeEntityButton_Clicked(object sender, EventArgs e) { SomeEntity someEntity; //Wrong way: //Get the entity from the webpage context someEntity = _webpageContext.SomeEntities.Single(s => s.Id == SomeEntityId); //Send the entity from _webpageContext to the engine _engine.ChangeSomeEntity(someEntity, SomeEntityNewValue); // <- oops, conflict of context //Right(?) way: //Get the entity from the engine context someEntity = _engine.GetSomeEntity(SomeEntityId); //undefined above //Send the entity from the engine's context to the engine _engine.ChangeSomeEntity(someEntity, SomeEntityNewValue); // <- oops, conflict of context } } Because the webpage has its own context, giving the Engine an entity from a different context will cause an error. I happen to know not to do that, to only give the Engine entities from its own context. But this is a very error-prone design. I see the error of my ways now. I just don't know the right path. I'm considering: Creating the connection in the Engine and passing it off to the webpage. Always instantiate an Engine, make its context accessible from a property, sharing it. Possible problems: other conflicts? Slow? Concurrency issues if I want to expand to AJAX? Creating the connection from the webpage and passing it off to the Engine (I believe that's dependency injection?) Only talking through ID's. Creates redundancy, not always practical, sounds archaic. But at the same time, I already recuperate stuff from the page as ID's that I need to fetch anyways. What would be best compromise here for safety, ease-of-use and understanding, stability, and speed?

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• Using multiple diagrams per model in Entity Framework 5.0

  - by nikolaosk

  I have downloaded .Net framework 4.5 and Visual Studio 2012 since it was released to MSDN subscribers on the 15th of August.For people that do not know about that yet please have a look at Jason Zander's excellent blog post .Since then I have been investigating the many new features that have been introduced in this release.In this post I will be looking into theIn order to follow along this post you must have Visual Studio 2012 and .Net Framework 4.5 installed in your machine.Download and install VS 20120 using this link.My machine runs on Windows 8 and Visual Studio 2012 works just fine. I have also installed in my machine SQL Server 2012 developer edition. I have also downloaded and installed AdventureWorksLT2012 database.You can download this database from the codeplex website.   Before I start showcasing the demo I want to say that I strongly believe that Entity Framework is maturing really fast and now at version 5.0 can be used as your data access layer in all your .Net projects.I have posted extensively about Entity Framework in my blog.Please find all the EF related posts here. In this demo I will show you how to split an entity model into multiple diagrams using the new enhanced EF designer. We will not build an application in this demo.Sometimes our model can become too large to edit or view.In earlier versions we could only have one diagram per EDMX file.In EF 5.0 we can split the model into more diagrams.1) Launch VS 2012. Express edition will work fine.2) Create a New Project. From the available templates choose a Web Forms application  3) Add a new item in your project, an ADO.Net Entity Data Model. I have named it AdventureWorksLT.edmx.Then we will create the model from the database and click Next.Create a new connection by specifying the SQL Server instance and the database name and click OK.Then click Next in the wizard.In the next screen of the wizard select all the tables from the database and hit Finish.4) It will take a while for our .edmx diagram to be created. When I select an Entity (e.g Customer) from my diagram and right click on it,a new option appears "Move to new Diagram".Make sure you have the Model Browser window open.Have a look at the picture below 5) When we do that a new diagram is created and our new Entity is moved there.Have a look at the picture below  6) We can also right-click and include the related entities. Have a look at the picture below. 7) When we do that the related entities are copied to the new diagram.Have a look at the picture below  8) Now we can cut (CTRL+X) the entities from Diagram2 and paste them back to Diagram1.9) Finally another great enhancement of the EF 5.0 designer is that you can change colors in the various entities that make up the model.Select the entities you want to change color, then in the Properties window choose the color of your choice. Have a look at the picture below. To recap we have demonstrated how to split your entity model in multiple diagrams which comes handy in EF models that have a large number of entities in them Hope it helps!!!!

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• Idera SQL Doctor 3.0 and MS SQL Changes

  New features worth mentioning in SQL doctor 3.0 begin with a new server dashboard that not only gives a comprehensive overview of a SQL Server instance's current health, but also several key details to help database administrators. Some of the details include recommendations on how to optimize server configuration, how to fix certain security issues, and how to get rid of performance bottlenecks. The latest version of SQL doctor also supplies users with key server information. The status of system parameters known to affect SQL Server performance, such as processes, disk partitions, cache, m...

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• Suggestions on documentation of a DB model when using Entity Framework 4

  - by Junior Ewing

  Any experiences on how to document Entity Framework 4 based Database projects? There is the Document and Summary properties on the Entities, but if we want to regenerate the model from the database at some point, it will be lost! Is there some way to map documentation data inside SQL to the Entities in the EDMX file so it is safe. Suggestions of other best practices? Ideally I want to be able to augo generate html/helpfile documentation from the DB when we deploy.

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• Sql Server xml column with Entity Framework - how to keep insignificant whitespaces

  - by Saravanan

  Sql server 2005 (even 2008) strips the insignificant whitespaces by default. To keep one can use the CONVERT funtction with the last argument as '1' (Ref. Article). How can we do the same thing in Entity Framework? thanks

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• Implementing features in an Entity System

  - by Bane

  After asking two questions on Entity Systems (1, 2), and reading some articles on them, I think that I understand them much better than before. But, I still have some uncertainties, and mainly they are about building a Particle Emitter, an Input system, and a Camera. I obviously still have some problems understanding Entity Systems, and they might apply to a whole other range of objects, but I chose these three because they are very different concepts and should cover a pretty big ground, and help me understand Entity Systems and how to handle problems like these myself, as they come along. I am building an engine in Javascript, and I've implemented most of the core features, which include: input handling, flexible animation system, particle emitter, math classes and functions, scene handling, a camera and a render, and a whole bunch of other things that engines usually support. Then, I read Byte56's answer that got me interested into making the engine into an Entity System one. It would still remain an HTML5 game engine with the basic Scene philosophy, but it should support dynamic creation of entities from components. These are some of the definitions from the previous questions, updated: An Entity is an identifier. It doesn't have any data, it's not an object, it's a simple id that represents an index in the Scene's list of all entities (which I actually plan to implement as a component matrix). A Component is a data holder, but with methods that can operate on that data. The best example is a Vector2D, or a "Position" component. It has data: x and y, but also some methods that make operating on the data a bit easier: add(), normalize(), and so on. A System is something that can operate on a set of entities that meet the certain requirements, usually they (the entities) need to have a specified (by the system itself) set of components to be operated upon. The system is the "logic" part, the "algorithm" part, all the functionality supplied by components is purely for easier data management. The problem that I have now is fitting my old engine concept into this new programming paradigm. Lets start with the simplest one, a Camera. The camera has a position property (Vector2D), a rotation property and some methods for centering it around a point. Each frame, it is fed to a renderer, along with a scene, and all the objects are translated according to it's position. Then the scene is rendered. How could I represent this kind of an object in an Entity System? Would the camera be an entity or simply a component? A combination (see my answer)? Another issues that is bothering me is implementing a Particle Emitter. For what exactly I mean by that, you can check out my video of it: http://youtu.be/BObargIMQsE. The problem I have with this is, again, what should be what. I'm pretty sure that particles themselves shouldn't be entities, as I want to support 10k+ of them, and creating that much entities would be a heavy blow on my performance, I believe. Or maybe not? Depends on the implementation, but anyone with experience: please, do answer. The last bit I wan't to talk about, which is also bugging me the most, is how input should be handled. In my current version of the engine, there is a class called Input. It's a handler that subscribes to browser's events, such as keypresses, and mouse position changes, and also it maintains an internal state. Then, the player class has a react() method, which accepts an input object as an argument. The advantage of this is that the input object could be serialized into JSON and then shared over the network, allowing for smooth multiplayer simulations. But how does this translate into an Entity System?

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• Efficiently separating Read/Compute/Write steps for concurrent processing of entities in Entity/Component systems

  - by TravisG

  Setup I have an entity-component architecture where Entities can have a set of attributes (which are pure data with no behavior) and there exist systems that run the entity logic which act on that data. Essentially, in somewhat pseudo-code: Entity { id; map<id_type, Attribute> attributes; } System { update(); vector<Entity> entities; } A system that just moves along all entities at a constant rate might be MovementSystem extends System { update() { for each entity in entities position = entity.attributes["position"]; position += vec3(1,1,1); } } Essentially, I'm trying to parallelise update() as efficiently as possible. This can be done by running entire systems in parallel, or by giving each update() of one system a couple of components so different threads can execute the update of the same system, but for a different subset of entities registered with that system. Problem In reality, these systems sometimes require that entities interact(/read/write data from/to) each other, sometimes within the same system (e.g. an AI system that reads state from other entities surrounding the current processed entity), but sometimes between different systems that depend on each other (i.e. a movement system that requires data from a system that processes user input). Now, when trying to parallelize the update phases of entity/component systems, the phases in which data (components/attributes) from Entities are read and used to compute something, and the phase where the modified data is written back to entities need to be separated in order to avoid data races. Otherwise the only way (not taking into account just "critical section"ing everything) to avoid them is to serialize parts of the update process that depend on other parts. This seems ugly. To me it would seem more elegant to be able to (ideally) have all processing running in parallel, where a system may read data from all entities as it wishes, but doesn't write modifications to that data back until some later point. The fact that this is even possible is based on the assumption that modification write-backs are usually very small in complexity, and don't require much performance, whereas computations are very expensive (relatively). So the overhead added by a delayed-write phase might be evened out by more efficient updating of entities (by having threads work more % of the time instead of waiting). A concrete example of this might be a system that updates physics. The system needs to both read and write a lot of data to and from entities. Optimally, there would be a system in place where all available threads update a subset of all entities registered with the physics system. In the case of the physics system this isn't trivially possible because of race conditions. So without a workaround, we would have to find other systems to run in parallel (which don't modify the same data as the physics system), other wise the remaining threads are waiting and wasting time. However, that has disadvantages Practically, the L3 cache is pretty much always better utilized when updating a large system with multiple threads, as opposed to multiple systems at once, which all act on different sets of data. Finding and assembling other systems to run in parallel can be extremely time consuming to design well enough to optimize performance. Sometimes, it might even not be possible at all because a system just depends on data that is touched by all other systems. Solution? In my thinking, a possible solution would be a system where reading/updating and writing of data is separated, so that in one expensive phase, systems only read data and compute what they need to compute, and then in a separate, performance-wise cheap, write phase, attributes of entities that needed to be modified are finally written back to the entities. The Question How might such a system be implemented to achieve optimal performance, as well as making programmer life easier? What are the implementation details of such a system and what might have to be changed in the existing EC-architecture to accommodate this solution?

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• Scripting a database copy from MS Sql 2005 to 2008 without detach/backup/RDP

  - by James Santiago

  My goal is to move a single SQL 2005 database to a seperate 2008 server. The issue is my level of access to both servers. On each I can only access the database and nothing else. I cant create a backup file or detach the database because I don't have access to the file system or to create a proxy. I've tried using the generate script function of sql 2005 management studio express to restore the schema but receive command not supported errors when attempting to execute the sql on the new database. Similarly I tried using EMS SQL Manager 2005 Lite to script a backup of the schema and data but ran into similar problems. How do I go about acomplishing this? I can't seem to find any solutions outside of using the detach and backup functions.

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• Generically correcting data before save with Entity Framework

  - by koevoeter

  Been working with Entity Framework (.NET 4.0) for a week now for a data migration job and needed some code that generically corrects string values in the database. You probably also have seen things like empty strings instead of NULL or non-trimmed texts ("United States       ") in "old" databases, and you don't want to apply a correcting function on every column you migrate. Here's how I've done this (extending the partial class of my ObjectContext):public partial class MyDatacontext{    partial void OnContextCreated()    {        SavingChanges += OnSavingChanges;    }     private void OnSavingChanges(object sender, EventArgs e)    {        foreach (var entity in GetPersistingEntities(sender))        {            foreach (var propertyInfo in GetStringProperties(entity))            {                var value = (string)propertyInfo.GetValue(entity, null);                 if (value == null)                {                    continue;                }                 if (value.Trim().Length == 0 && IsNullable(propertyInfo))                {                    propertyInfo.SetValue(entity, null, null);                }                else if (value != value.Trim())                {                    propertyInfo.SetValue(entity, value.Trim(), null);                }            }        }    }     private IEnumerable<object> GetPersistingEntities(object sender)    {        return ((ObjectContext)sender).ObjectStateManager            .GetObjectStateEntries(EntityState.Added | EntityState.Modified)             .Select(e => e.Entity);    }    private IEnumerable<PropertyInfo> GetStringProperties(object entity)    {        return entity.GetType().GetProperties()            .Where(pi => pi.PropertyType == typeof(string));    }    private bool IsNullable(PropertyInfo propertyInfo)    {        return ((EdmScalarPropertyAttribute)propertyInfo             .GetCustomAttributes(typeof(EdmScalarPropertyAttribute), false)            .Single()).IsNullable;    }}   Obviously you can use similar code for other generic corrections.

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• Validate a string in a table in SQL Server - CLR function or T-SQL

  - by Ashish Gupta

  I need to check If a column value (string) in SQL server table starts with a small letter and can only contain '_', '-', numbers and alphabets. I know I can use a SQL server CLR function for that. However, I am trying to implement that validation using a scalar UDF and could make very little here...I can use 'NOT LIKE', but I am not sure how to make sure I validate the string irrespective of the order of characters or in other words write a pattern in SQL for this. Am I better off using a SQL CLR function? Any help will be appreciated.. Thanks in advance Thank you everyone for their comments. This morning, I chose to go CLR function way. For the purpose of what I was trying to achieve, I created one CLR function which does the validation of an input string and have that called from a SQL UDF and It works well. Just to measure the performance of t-SQL UDF using SQL CLR function vs t- SQL UDF, I created a SQL CLR function which will just check if the input string contains only small letters, it should return true else false and have that called from a UDF (IsLowerCaseCLR). After that I also created a regular t-SQL UDF(IsLowerCaseTSQL) which does the same thing using the 'NOT LIKE'. Then I created a table (Person) with columns Name(varchar) and IsValid(bit) columns and populate that with names to test. Data :- 1000 records with 'Ashish' as value for Name column 1000 records with 'ashish' as value for Name column then I ran the following :- UPDATE Person Set IsValid=1 WHERE dbo.IsLowerCaseTSQL (Name) Above updated 1000 records (with Isvalid=1) and took less than a second. I deleted all the data in the table and repopulated the same with same data. Then updated the same table using Sql CLR UDF (with Isvalid=1) and this took 3 seconds! If update happens for 5000 records, regular UDF takes 0 seconds compared to CLR UDF which takes 16 seconds! I am very less knowledgeable on t-SQL regular expression or I could have tested my actual more complex validation criteria. But I just wanted to know, even I could have written that, would that have been faster than the SQL CLR function considering the example above. Are we using SQL CLR because we can implement we can implement lot richer logic which would have been difficult otherwise If we write in regular SQL. Sorry for this long post. I just want to know from the experts. Please feel free to ask if you could not understand anything here. Thank you again for your time.

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• Validate a string in a table in SQL Server - CLR function or T-SQL (Question updated)

  - by Ashish Gupta

  I need to check If a column value (string) in SQL server table starts with a small letter and can only contain '_', '-', numbers and alphabets. I know I can use a SQL server CLR function for that. However, I am trying to implement that validation using a scalar UDF and could make very little here...I can use 'NOT LIKE', but I am not sure how to make sure I validate the string irrespective of the order of characters or in other words write a pattern in SQL for this. Am I better off using a SQL CLR function? Any help will be appreciated.. Thanks in advance Thank you everyone for their comments. This morning, I chose to go CLR function way. For the purpose of what I was trying to achieve, I created one CLR function which does the validation of an input string and have that called from a SQL UDF and It works well. Just to measure the performance of t-SQL UDF using SQL CLR function vs t- SQL UDF, I created a SQL CLR function which will just check if the input string contains only small letters, it should return true else false and have that called from a UDF (IsLowerCaseCLR). After that I also created a regular t-SQL UDF(IsLowerCaseTSQL) which does the same thing using the 'NOT LIKE'. Then I created a table (Person) with columns Name(varchar) and IsValid(bit) columns and populate that with names to test. Data :- 1000 records with 'Ashish' as value for Name column 1000 records with 'ashish' as value for Name column then I ran the following :- UPDATE Person Set IsValid=1 WHERE dbo.IsLowerCaseTSQL (Name) Above updated 1000 records (with Isvalid=1) and took less than a second. I deleted all the data in the table and repopulated the same with same data. Then updated the same table using Sql CLR UDF (with Isvalid=1) and this took 3 seconds! If update happens for 5000 records, regular UDF takes 0 seconds compared to CLR UDF which takes 16 seconds! I am very less knowledgeable on t-SQL regular expression or I could have tested my actual more complex validation criteria. But I just wanted to know, even I could have written that, would that have been faster than the SQL CLR function considering the example above. Are we using SQL CLR because we can implement we can implement lot richer logic which would have been difficult otherwise If we write in regular SQL. Sorry for this long post. I just want to know from the experts. Please feel free to ask if you could not understand anything here. Thank you again for your time.

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• Using SQL dB column as a lock for concurrent operations in Entity Framework

  - by Sid

  We have a long running user operation that is handled by a pool of worker processes. Data input and output is from Azure SQL. The master Azure SQL table structure columns are approximated to [UserId, col1, col2, ... , col N, beingProcessed, lastTimeProcessed ] beingProcessed is boolean and lastTimeProcessed is DateTime. The logic in every worker role is: public void WorkerRoleMain() { while(true) { try { dbContext db = new dbContext(); // Read foreach (UserProfile user in db.UserProfile .Where(u => DateTime.UtcNow.Subtract(u.lastTimeProcessed) > TimeSpan.FromHours(24) & u.beingProcessed == false)) { user.beingProcessed = true; // Modify db.SaveChanges(); // Write // Do some long drawn processing here ... ... ... user.lastTimeProcessed = DateTime.UtcNow; user.beingProcessed = false; db.SaveChanges(); } } catch(Exception ex) { LogException(ex); Sleep(TimeSpan.FromMinutes(5)); } } // while () } With multiple workers processing as above (each with their own Entity Framework layer), in essence beingProcessed is being used a lock for MutEx purposes Question: How can I deal with concurrency issues on the beingProcessed "lock" itself based on the above load? I think read-modify-write operation on the beingProcessed needs to be atomic but I'm open to other strategies. Open to other code refinements too.

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• SQL Server and Hyper-V Dynamic Memory Part 3

  - by SQLOS Team

  In parts 1 and 2 of this series we looked at the basics of Hyper-V Dynamic Memory and SQL Server memory management. In this part Serdar looks at configuration guidelines for SQL Server memory management. Part 3: Configuration Guidelines for Hyper-V Dynamic Memory and SQL Server Now that we understand SQL Server Memory Management and Hyper-V Dynamic Memory basics, let’s take a look at general configuration guidelines in order to utilize benefits of Hyper-V Dynamic Memory in your SQL Server VMs. Requirements Host Operating System Requirements Hyper-V Dynamic Memory feature is introduced with Windows Server 2008 R2 SP1. Therefore in order to use Dynamic Memory for your virtual machines, you need to have Windows Server 2008 R2 SP1 or Microsoft Hyper-V Server 2008 R2 SP1 in your Hyper-V host. Guest Operating System Requirements In addition to this Dynamic Memory is only supported in Standard, Web, Enterprise and Datacenter editions of windows running inside VMs. Make sure that your VM is running one of these editions. For additional requirements on each operating system see “Dynamic Memory Configuration Guidelines” here. SQL Server Requirements All versions of SQL Server support Hyper-V Dynamic Memory. However, only certain editions of SQL Server are aware of dynamically changing system memory. To have a truly dynamic environment for your SQL Server VMs make sure that you are running one of the SQL Server editions listed below: ·         SQL Server 2005 Enterprise ·         SQL Server 2008 Enterprise / Datacenter Editions ·         SQL Server 2008 R2 Enterprise / Datacenter Editions Configuration guidelines for other versions of SQL Server are covered below in the FAQ section. Guidelines for configuring Dynamic Memory Parameters Here is how to configure Dynamic Memory for your SQL VMs in a nutshell: Hyper-V Dynamic Memory Parameter Recommendation Startup RAM 1 GB + SQL Min Server Memory Maximum RAM > SQL Max Server Memory Memory Buffer % 5 Memory Weight Based on performance needs   Startup RAM In order to ensure that your SQL Server VMs can start correctly, ensure that Startup RAM is higher than configured SQL Min Server Memory for your VMs. Otherwise SQL Server service will need to do paging in order to start since it will not be able to see enough memory during startup. Also note that Startup Memory will always be reserved for your VMs. This will guarantee a certain level of performance for your SQL Servers, however setting this too high will limit the consolidation benefits you’ll get out of your virtualization environment. Maximum RAM This one is obvious. If you’ve configured SQL Max Server Memory for your SQL Server, make sure that Dynamic Memory Maximum RAM configuration is higher than this value. Otherwise your SQL Server will not grow to memory values higher than the value configured for Dynamic Memory. Memory Buffer % Memory buffer configuration is used to provision file cache to virtual machines in order to improve performance. Due to the fact that SQL Server is managing its own buffer pool, Memory Buffer setting should be configured to the lowest value possible, 5%. Configuring a higher memory buffer will prevent low resource notifications from Windows Memory Manager and it will prevent reclaiming memory from SQL Server VMs. Memory Weight Memory weight configuration defines the importance of memory to a VM. Configure higher values for the VMs that have higher performance requirements. VMs with higher memory weight will have more memory under high memory pressure conditions on your host. Questions and Answers Q1 – Which SQL Server memory model is best for Dynamic Memory? The best SQL Server model for Dynamic Memory is “Locked Page Memory Model”. This memory model ensures that SQL Server memory is never paged out and it’s also adaptive to dynamically changing memory in the system. This will be extremely useful when Dynamic Memory is attempting to remove memory from SQL Server VMs ensuring no SQL Server memory is paged out. You can find instructions on configuring “Locked Page Memory Model” for your SQL Servers here. Q2 – What about other SQL Server Editions, how should I configure Dynamic Memory for them? Other editions of SQL Server do not adapt to dynamically changing environments. They will determine how much memory they should allocate during startup and don’t change this value afterwards. Therefore make sure that you configure a higher startup memory for your VM because that will be all the memory that SQL Server utilize Tune Maximum Memory and Memory Buffer based on the other workloads running on the system. If there are no other workloads consider using Static Memory for these editions. Q3 – What if I have multiple SQL Server instances in a VM? Having multiple SQL Server instances in a VM is not a general recommendation for predictable performance, manageability and isolation. In order to achieve a predictable behavior make sure that you configure SQL Min Server Memory and SQL Max Server Memory for each instance in the VM. And make sure that: ·         Dynamic Memory Startup Memory is greater than the sum of SQL Min Server Memory values for the instances in the VM ·         Dynamic Memory Maximum Memory is greater than the sum of SQL Max Server Memory values for the instances in the VM Q4 – I’m using Large Page Memory Model for my SQL Server. Can I still use Dynamic Memory? The short answer is no. SQL Server does not dynamically change its memory size when configured with Large Page Memory Model. In virtualized environments Hyper-V provides large page support by default. Most of the time, Large Page Memory Model doesn’t bring any benefits to a SQL Server if it’s running in virtualized environments. Q5 – How do I monitor SQL performance when I’m trying Dynamic Memory on my VMs? Use the performance counters below to monitor memory performance for SQL Server: Process - Working Set: This counter is available in the VM via process performance counters. It represents the actual amount of physical memory being used by SQL Server process in the VM. SQL Server – Buffer Cache Hit Ratio: This counter is available in the VM via SQL Server counters. This represents the paging being done by SQL Server. A rate of 90% or higher is desirable. Conclusion These blog posts are a quick start to a story that will be developing more in the near future. We’re still continuing our testing and investigations to provide more detailed configuration guidelines with example performance numbers with a white paper in the upcoming months. Now it’s time to give SQL Server and Hyper-V Dynamic Memory a try. Use this guidelines to kick-start your environment. See what you think about it and let us know of your experiences. - Serdar Sutay Originally posted at http://blogs.msdn.com/b/sqlosteam/

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• How to join dynamic sql statement in variable with normal statement

  - by Oliver

  I have a quite complicated query which will by built up dynamically and is saved in a variable. As second part i have another normal query and i'd like to make an inner join between these both. To make it a little more easier here is a little example to illustrate my problem. For this little example i used the AdventureWorks database. Some query built up dynamically (Yes, i know here is nothing dynamic here, cause it's just an example.) DECLARE @query AS varchar(max) ; set @query = ' select HumanResources.Employee.EmployeeID ,HumanResources.Employee.LoginID ,HumanResources.Employee.Title ,HumanResources.EmployeeAddress.AddressID from HumanResources.Employee inner join HumanResources.EmployeeAddress on HumanResources.Employee.EmployeeID = HumanResources.EmployeeAddress.EmployeeID ;'; EXEC (@query); The normal query i have select Person.Address.AddressID ,Person.Address.City from Person.Address Maybe what i'd like to have but doesn't work select @query.* ,Addresses.City from @query as Employees inner join ( select Person.Address.AddressID ,Person.Address.City from Person.Address ) as Addresses on Employees.AddressID = Addresses.AddressID

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• sql 2008 metadata modified date

  - by Kumar

  Is there a way to identify the timestamp when an object(table/view/stored proc...) was modified ? there's a refdate in sysobjects but it's always the same as crdate atleast in my case and i know that alter view/alter table/alter proc commands have been run many times post creation

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• Use SQL to filter the results of a stored procedure

  - by Ben McCormack

  I've looked at other questions on Stack Overflow related to this question, but none of them seemed to answer this question clearly. We have a system Stored Procedure called sp_who2 which returns a result set of information for all running processes on the server. I want to filter the data returned by the stored procedure; conceptually, I might do it like so: SELECT * FROM sp_who2 WHERE login='bmccormack' That method, though, doesn't work. What are good practices for achieving the goal of querying the returned data of a stored procedure, preferably without having to look of the code of the original stored procedure and modify it.

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• t-sql recursive query

  - by stackoverflowuser

  Based on an existing table I used CTE recursive query to come up with following data. But failing to apply it a level further. Data is as below id name parentid -------------------------- 1 project 0 2 structure 1 3 path_1 2 4 path_2 2 5 path_3 2 6 path_4 3 7 path_5 4 8 path_6 5 I want to recursively form full paths from the above data. Means the recursion will give the following output. FullPaths ------------- Project Project\Structure Project\Structure\Path_1 Project\Structure\Path_2 Project\Structure\Path_3 Project\Structure\Path_1\path_4 Project\Structure\Path_2\path_5 Project\Structure\Path_3\path_6 Thanks

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• Stored Procedure To Search the AccessRights given to the Users.

  - by thevan

  Hi, I want to display the Access Rights given to the Users for the particular module. I have Seven Tables such as RoleAccess, Roles, Functions, Module, SubModule, Company and Unit. RoleAccess is the Main Table. The AccessRights given will be stored in the RoleAccess Table only. RoleAccess Table has the following columns such as RoleID, CompanyID, UnitID, FunctionID, ModuleID, SubModuleID, Create, Update, Delete, Read, Approve. Here Create_f, Update_f, Delete_f, Read_f and Approve_f are flags. Company Table has two columns such as CompanyID and CompanyName. Unit Table has three columns such as UnitID, UnitName and CompanyID. Roles Table has four columns such as RoleID, RoleName, CompanyID and UnitID. Module Table has two columns such as ModuleID and ModuleName. SubModule Table has three columns such as ModuleID, SubModuleID, SubModuleName. Functions Table has five columns such as FunctionID, FunctionName, ModuleID and SubModuleID. At First, The RoleAccess Table does not contain any records. So I want to display the ModuleName, SubModuleName, FunctionName, CompanyID, RoleID, UnitID, FunctionID, ModuleID, SubModuleID, Create_f, Update_f, Delete_f, Read_f and Approve_f. If the AccessRights is assigned to the Particular RoleID means the flags in the search results will be 1 else it will be 0. I have witten one stored procedure but it displays the records based on the RoleID stored in the RoleAccess table. But I also want to display the Flags as 0 for the Roles not stored in the RoleAccess Table. I want the Stored Procedure for this. Any one please help me.

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• How to Track Number of Changes Occured in a Column? T-SQL - SQL Server

  - by user327387

  For example, i have a column named EmployeeName. Every time a user changes/fix his name, i need to keep a count. If he changes his name twice, then count is 2. Also, i need to store the time of every change employee makes on EmployeeName e.g. if the name essentially is James and time created is 9:00 AM and then employee changes to John on 11:00 AM, i need to preserve this new time and new value as well as the previous one which is James at 9:00 AM. I hope its clear! Thank you guys...Best Answer will be chosen... If this requires a trigger, giving a sketchy pseudo-code will be very much appreciated.

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• The SQL Server Setup Portal

  - by BuckWoody

  One of the tasks that takes a long time for the data professional is setting up SQL Server. No, it isn’t that difficult to slide a DVD in a drive and click “Setup” but the overall process of planning the hardware and software environment, making decisions for high-availability, security and dozens of other choices can make the process more difficult. And then, of course, there are the inevitable issues that arise. Microsoft supports literally hundreds and even thousands of combinations of hardware and software drivers from vendors you’ve never even heard of. Making all of that work together is a small miracle, so things are bound to arise that you need to deal with. So, to help you out, we’ve designed a new “SQL Server Setup Portal”. It’s a one-stop-shop for everything you need to know about planning and setting up SQL Server. As time goes on you’ll see even more content added. There are already whitepapers, videos, and multiple places to search on everything from topic names to error codes. So go check it out – and if you have to do a lot of SQL Server Setups – and especially if you don’t – bookmark it as a favorite! Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• How would I design this table in SQL?

  - by RSharma

  I have a parent master table that is generic enough to hold the common information of the children. Since the children were substantially different, we created separate tables for them. So I have something like this: tblMaster -------- MasterID int Name varchar(50) --Common to all children and there are a bunch of fields like this ChildType int -- Type of Child either ChildOne or ChildTwo ChildID int -- need to store ChildOneID or ChildTwoID depending on type of Child, so that i can refer to children tblChild1 -------- ChildOneID int IDENTITY tblChild2 --------- ChildTwoID int IDENTITY Should I have a ChildID in the master that is either ChildOneID or ChildTwoID based on the ChildType column? I have a number of children and I have simplified it for this question. The other way is to add ChildOneID and ChildTwoID as columns in the master, but since i have a number of columns, I will have a lot of null columns EDIT: Any help is appreciated

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• Create an Integrity error for an SQL Server Database for the purpose of Testing

  - by CaptainPhil

  How can I manually introduce an integrity error into my database for the purpose of testing, without totally corrupting the database so that I can still run my program.

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• Entity Framework v1 &hellip; Brief Synopsis and Tips &ndash; Part 2

  - by Rohit Gupta

  Using Entity Framework with ASMX Web sErvices and WCF Web Service: If you use ASMX WebService to expose Entity objects from Entity Framework... then the ASMX Webservice does not  include object graphs, one work around is to use Facade pattern or to use WCF Service. The other important aspect of using ASMX Web Services along with Entity Framework is that the ASMX Client is not aware of the existence of EF v1 since the client solely deals with C# objects (not EntityObjects or ObjectContext). Since the client is not aware of the ObjectContext hence the client cannot participate in change tracking since the client only receives the Current Values and not the Orginal values when the service sends the the Entity objects to the client. Thus there are 2 drawbacks to using EntityFramework with ASMX Web Service: 1. Object state is not maintained... so to overcome this limitation we need insert/update single entity at a time and retrieve the original values for the entity being updated on the server/service end before calling Save Changes. 2. ASMX does not maintain object graphs... i.e. Customer.Reservations or Customer.Reservations.Trip relationships are not maintained. Thus you need to send these relationships separately from service to client. WCF Web Service overcomes the object graph limitation of ASMX Web Service, but we need to insure that we are populating all the non-null scalar properties of all the objects in the object graph before calling Update. WCF Web service still cannot overcome the second limitation of tracking changes to entities at the client end. Also note that the "Customer" class in the Client is very different from the "Customer" class in the Entity Framework Model Entities. They are incompatible with each other hence we cannot cast one to the other. However the .NET Framework translates the client "Customer" Entity to the EFv1 Model "customer" Entity once the entity is serialzed back on the ASMX server end. If you need change tracking enabled on the client then we need to use WCF Data Services which is available with VS 2010. ====================================================================================================== In WCF when adding an object that has relationships, the framework assumes that every object in the object graph needs to be added to store. for e.g. in a Customer.Reservations.Trip object graph, when a Customer Entity is added to the store, the EFv1 assumes that it needs to a add a Reservations collection and also Trips for each Reservation. Thus if we need to use existing Trips for reservations then we need to insure that we null out the Trip object reference from Reservations and set the TripReference to the EntityKey of the desired Trip instead. ====================================================================================================== Understanding Relationships and Associations in EFv1 The Golden Rule of EF is that it does not load entities/relationships unless you ask it to explicitly do so. However there is 1 exception to this rule. This exception happens when you attach/detach entities from the ObjectContext. If you detach an Entity in a ObjectGraph from the ObjectContext, then the ObjectContext removes the ObjectStateEntry for this Entity and all the relationship Objects associated with this Entity. For e.g. in a Customer.Order.OrderDetails if the Customer Entity is detached from the ObjectContext then you cannot traverse to the Order and OrderDetails Entities (that still exist in the ObjectContext) from the Customer Entity(which does not exist in the Object Context) Conversely, if you JOIN a entity that is not in the ObjectContext with a Entity that is in the ObjContext then the First Entity will automatically be added to the ObjContext since relationships for the 2 Entities need to exist in the ObjContext. ========================================================= You cannot attach an EntityCollection to an entity through its navigation property for e.g. you cannot code myContact.Addresses = myAddressEntityCollection ========================================================== Cascade Deletes in EDM: The Designer does not support specifying cascase deletes for a Entity. To enable cascasde deletes on a Entity in EDM use the Association definition in CSDL for the Entity. for e.g. SalesOrderDetail (SOD) has a Foreign Key relationship with SalesOrderHeader (SalesOrderHeader 1 : SalesOrderDetail *) if you specify a cascade Delete on SalesOrderHeader Entity then calling deleteObject on SalesOrderHeader (SOH) Entity will send delete commands for SOH record and all the SOD records that reference the SOH record. ========================================================== As a good design practise, if you use Cascade Deletes insure that Cascade delete facet is used both in the EDM as well as in the database. Even though it is not absolutely mandatory to have Cascade deletes on both Database and EDM (since you can see that just the Cascade delete spec on the SOH Entity in EDM will insure that SOH record and all related SOD records will be deleted from the database ... even though you dont have cascade delete configured in the database in the SOD table) ============================================================== Maintaining relationships in Code When Setting a Navigation property of a Entity (for e.g. setting the Contact Navigation property of Address Entity) the following rules apply : If both objects are detached, no relationship object will be created. You are simply setting a property the CLR way. If both objects are attached, a relationship object will be created. If only one of the objects is attached, the other will become attached and a relationship object will be created. If that detached object is new, when it is attached to the context its EntityState will be Added. One important rule to remember regarding synchronizing the EntityReference.Value and EntityReference.EntityKey properties is that when attaching an Entity which has a EntityReference (e.g. Address Entity with ContactReference) the Value property will take precedence and if the Value and EntityKey are out of sync, the EntityKey will be updated to match the Value. ====================================================== If you call .Load() method on a detached Entity then the .Load() operation will throw an exception. There is one exception to this rule. If you load entities using MergeOption.NoTracking, you will be able to call .Load() on such entities since these Entities are accessible by the ObjectContext. So the bottomline is that we need Objectontext to be able to call .Load() method to do deffered loading on EntityReference or EntityCollection. Another rule to remember is that you cannot call .Load() on entities that have a EntityState.Added State since the ObjectContext uses the EntityKey of the Primary (Parent) Entity when loading the related (Child) Entity (and not the EntityKey of the child (even if the EntityKey of the child is present before calling .Load()) ====================================================== You can use ObjContext.Add() to add a entity to the ObjContext and set the EntityState of the new Entity to EntityState.Added. here no relationships are added/updated. You can also use EntityCollection.Add() method to add an entity to another entity's related EntityCollection for e.g. contact has a Addresses EntityCollection so to add a new address use contact.Addresses.Add(newAddress) to add a new address to the Addresses EntityCollection. Note that if the entity does not already exist in the ObjectContext then calling contact.Addresses.Add(myAddress) will cause a new Address Entity to be added to the ObjContext with EntityState.Added and it will also add a RelationshipEntry (a relationship object) with EntityState.Added which connects the Contact (contact) with the new address newAddress. Note that if the entity already exists in the Objectcontext (being part theOtherContact.Addresses Collection), then calling contact.Addresses.Add(existingAddress) will add 2 RelationshipEntry objects to the ObjectStateEntry Collection, one with EntityState.Deleted and the other with EntityState.Added. This implies that the existingAddress Entity is removed from the theOtherContact.Addresses Collection and Added to the contact.Addresses Collection..effectively reassigning the address entity from the theOtherContact to "contact". This is called moving an existing entity to a new object graph. ====================================================== You usually use ObjectContext.Attach() and EntityCollection.Attach() methods usually when you need to reconstruct the ObjectGraph after deserializing the objects as received from a ASMX Web Service Client. Attach is usually used to connect existing Entities in the ObjectContext. When EntityCollection.Attach() is called the EntityState of the RelationshipEntry (the relationship object) remains as EntityState.unchanged whereas when EntityCollection.Add() method is called the EntityState of the relationship object changes to EntityState.Added or EntityState.Deleted as the situation demands. ========================================================= LINQ To Entities Tips: Select Many does Inner Join by default.   for e.g. from c in Contact from a in c.Address select c ... this will do a Inner Join between the Contacts and Addresses Table and return only those Contacts that have a Address. ======================================================== Group Joins Do LEFT Join by default. e.g. from a in Address join c in Contact ON a.Contact.ContactID == c.ContactID Into g WHERE a.CountryRegion == "US" select g; This query will do a left join on the Contact table and return contacts that have a address in "US" region The following query : from c in Contact join a in Address.Where(a1 => a1.CountryRegion == "US") on c.ContactID  equals a.Contact.ContactID into addresses select new {c, addresses} will do a left join on the Address table and return All Contacts. In these Contacts only those will have its Address EntityCollection Populated which have a Address in the "US" region, the other contacts will have 0 Addresses in the Address collection (even if addresses for those contacts exist in the database but are in a different region) ======================================================== Linq to Entities does not support DefaultIfEmpty().... instead use .Include("Address") Query Builder method to do a Left JOIN or use Group Joins if you need more control like Filtering on the Address EntityCollection of Contact Entity =================================================================== Use CreateSourceQuery() on the EntityReference or EntityCollection if you need to add filters during deferred loading of Entities (Deferred loading in EFv1 happens when you call Load() method on the EntityReference or EntityCollection. for e.g. var cust=context.Contacts.OfType<Customer>().First(); var sq = cust.Reservations.CreateSourceQuery().Where(r => r.ReservationDate > new DateTime(2008,1,1)); cust.Reservations.Attach(sq); This populates only those reservations that are older than Jan 1 2008. This is the only way (in EFv1) to Attach a Range of Entities to a EntityCollection using the Attach() method ================================================================== If you need to get the Foreign Key value for a entity e.g. to get the ContactID value from a Address Entity use this :                                address.ContactReference.EntityKey.EntityKeyValues.Where(k=> k.Key == "ContactID")

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• T-SQL Tuesday #15 : Running T-SQL workloads remotely on multiple servers

  - by AaronBertrand

  This month's installment of T-SQL Tuesday is hosted by Pat Wright ( blog | twitter ). Pat says: "So the topic I have chosen for this month is Automation! It can be Automation with T-SQL or with Powershell or a mix of both. Give us your best tips/tricks and ideas for making our lives easier through Automation." In a recent project, we've had a need to run concurrent workloads on as many as 100 instances of SQL Server in a test environment. A goal, obviously, is to accomplish this without having to...(read more)

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