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  • PHP edit unique row in table

    - by Robert
    I currently have a PHP form that uses AJAX to connect to MySQL and display records matching a user's selection (http://stackoverflow.com/questions/2593317/ajax-display-mysql-data-with-value-from-multiple-select-boxes) As well as displaying the data, I also place an 'Edit' button next to each result which displays a form where the data can be edited. My problem is editing unique records since currently I only use the selected values for 'name' and 'age' to find the record. If two (or more) records share the same name and age, I am only able to edit the first result.

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  • How to set up global connect to datebase in pylons(python), sqlalchemy.

    - by gummmibear
    Hi! I just start lern python, pylons. i have problem with setting up datebase connection. i won't to set connection, where i can see this connection in all my controllers. Now i use: some thing like this in my controller: 45 ' db = create_engine('mysql://root:password@localhost/python') 46 ' metadata = MetaData(db) 47 48 ' email_list = Table('email',metadata,autoload=True) in development.ini i have: 44 sqlalchemy.url = mysql://root@password@localhost/python 45 sqlalchemy.pool_recycle = 3600 and now, pleas help me to set __init__.py

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  • Combining multiple classes gives me errors

    - by Martti Laine
    Hello I'm creating a website with structure like this: class main { } class mysql extends main { } class user extends main { } class etc extends main { } The idea is for these classes to use functions from each other. This doesn't work. How can I call a function from mysql in user? Martti Laine

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  • Freebase; select a random record?

    - by user168083
    1) Is there any way to select a random record from Freebase? If I do a limit of 1, it consistently returns the same record. I could grab the larger data set and select a random rec from that but that seems like overkill. Analogous to MySQL's : select * from profiles order by rand() limit 1; 2) Is there any way to tell Freebase not to select certain items in a set? Analogous to MySQL's : select * from profiles where id NOT IN (SELECT profile_id from approved_profiles) Thanks in advance

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  • PostgreSQL + Rails citext

    - by glebm
    I am trying to move to heroku which uses PostgreSQL 8.4 which has a citext column type which is nice since the app was written for MySQL. Is there any way to use :citext with rails (so that if the migrations are run on MySQL the citext would just use string/text? I found this ticket, but it seems like it isn't going to be a part of rails for a while: https://rails.lighthouseapp.com/projects/8994/tickets/3174-add-support-for-postgresql-citext-column-type

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  • SQL Native Client 10 Performance miserable (due to server-side cursors)

    - by namezero
    we have an application that uses ODBC via CDatabase/CRecordset in MFC (VS2010). We have two backends implemented. MSSQL and MySQL. Now, when we use MSSQL (with the Native Client 10.0), retrieving records with SELECT is dramatically slow via slow links (VPN, for example). The MySQL ODBC driver does not exhibit this nasty behavior. For example: CRecordset r(&m_db); r.Open(CRecordset::snapshot, L"SELECT a.something, b.sthelse FROM TableA AS a LEFT JOIN TableB AS b ON a.ID=b.Ref"); r.MoveFirst(); while(!r.IsEOF()) { // Retrieve CString strData; crs.GetFieldValue(L"a.something", strData); crs.MoveNext(); } Now, with the MySQL driver, everything runs as it should. The query is returned, and everything is lightning fast. However, with the MSSQL Native Client, things slow down, because on every MoveNext(), the driver communicates with the server. I think it is due to server-side cursors, but I didn't find a way to disable them. I have tried using: ::SQLSetConnectAttr(m_db.m_hdbc, SQL_ATTR_ODBC_CURSORS, SQL_CUR_USE_ODBC, SQL_IS_INTEGER); But this didn't help either. There are still long-running exec's to sp_cursorfetch() et al in SQL Profiler. I have also tried a small reference project with SQLAPI and bulk fetch, but that hangs in FetchNext() for a long time, too (even if there is only one record in the resultset). This however only happens on queries with LEFT JOINS, table-valued functions, etc. Note that the query doesn't take that long - executing the same SQL via SQL Studio over the same connection returns in a reasonable time. Question1: Is is possible to somehow get the native client to "cache" all results locally use local cursors in a similar fashion as the MySQL driver seems to do it? Maybe this is the wrong approach altogether, but I'm not sure how else to do this. All we want is to retrieve all data at once from a SELECT, then never talk the server again until the next query. We don't care about recordset updates, deletes, etc or any of that nonsense. We only want to retrieve data. We take that recordset, get all the data, and delete it. Question2: Is there a more efficient way to just retrieve data in MFC with ODBC?

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  • Creating application using rails 2.3.5 and cassandra database

    - by Joshi
    hi all, Pls guide me how to create rails application using rails 2.3.5 and cassandra database as rails 2.3.5 supports mysql, sqllite etc. I typed in the command prompt like this $ rails -d cassandra myapp Databases supported for preconfiguration are: mysql, oracle, postgresql, sqlite2, sqlite3, frontbase, ibm_db So pls help me in this regard

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  • Display ny website source code for copy/paste

    - by AlexGuz
    Hi everyone... I have a website displaying data from MySQL in a php file (/something.php).... i want to copy the source code of that page as HTML so i can use it in a textfield box so users can copy paste that code... It's almost like an HTML generator using info from mySQL, so users can custimize each HTML code. I have everything covered... except the display HTML thing. Please Help

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  • Display any website source code for copy/paste

    - by AlexGuz
    Hi everyone... I have a website displaying data from MySQL in a php file (/something.php).... i want to copy the source code of that page as HTML so i can use it in a textfield box so users can copy paste that code... It's almost like an HTML generator using info from mySQL, so users can custimize each HTML code. I have everything covered... except the display HTML thing. Please Help

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  • How to create Insert script using c#

    - by karthik
    From my c# code behind, i pass a query to mysql database and get the data in a DataTable. Now i want to use the data in data table to write the Insert query in a script file [.sql] The objective of doing so is, whatever records i select from mysql, i should write that to a script file as backup. Thais why i need the insert statements. How ? Or any other idea is appreciated.

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  • Not able to connect the DB from Servlet

    - by user1885127
    I have started jsp servlet application with Xampp Server, In which I have dbconnection.java and LoginValidator.java (servlet) files. I'm getting an error while trying to access the database from servlet (LoginValidator.java). It is getting the following error: Class Not found Exception : com.mysql.jdbc.Driver I have imported the mysql-connector-java-5.1.18-bin.jar. I have searched a lot but could not find the solution.

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  • clear command in my mac os terminal gives the following error

    - by sil
    dyld: Library not loaded: /opt/local/lib/libncursesw.5.dylib Referenced from: /opt/local/bin/clear Reason: image not found Trace/BPT trap This is what my bash_login looks like: export PATH="/usr/local/bin:/usr/local/sbin:/usr/local/mysql/bin:$PATH" export PATH="/usr/local/apache-maven-2.2.1/bin:$PATH" export PATH="~/.gem/ruby/1.8/bin:$PATH" export PATH="/usr/local/mysql/bin:$PATH" export PATH="/System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home/bin:$PATH" export PATH=/opt/local/bin:/opt/local/sbin:$PATH export MANPATH=/opt/local/share/man:$MANPATH

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  • How to connect PHPMyadmin DB by creating the batch file.

    - by Dev
    Hi All, I have created the sql file to create table in DB, I am using PHPMYAdmin But i am not able to connect to the DB, I want to run this as Batch file. If i try to MYSQL from command prompt it give error as 'mysql' is not recognized as an internal or external command, operable program or batch file. Regards, Dev

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  • what databases can be used with java?

    - by aadersh patel
    I am doing an undergrad final project, and need to justify my choice of MySQL for the database element of my project. Truth is, it's the only one I can really use, and hence I went for it. What other database systems could I have used? Any advantages and disadvantages of these over MySQL?

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  • What is a good free ODBC viewer?

    - by wshato
    At my job I have to work with three different databases. One is a SQL Server 2008, for which I use SQL Server Management Studio, and another is MySQL, for which I use the MySQL tools. The third however is a Cache database that I can only access through a ODBC connection. Currently I use the SLIK software ODBC View tool to access it, but it is severely lacking when compared with the other two tools. Can anyone recommend a good tool for this type of work?

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  • replacing characters with UTF-8 after using mysql_set_charset('utf8') function

    - by Ahmet vardar
    I converted all mysql tables to utf-8_unicode and started using mysql_set_charset('utf8'); function. But after this, some characters like S, Ö started looking like Ö , Åž How can i replace this kinda letters in mysql with UTF-8 format ? shortly, can i find a list of all these kinda characters to replace ? EDIT: He is explaining about this issue in this article actually but i cannot understand it properly acutally lol http://www.oreillynet.com/onlamp/blog/2006/01/turning_mysql_data_in_latin1_t.html

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  • Best way for an external (remote) graphics designer to style ASP.NET MVC 4 app?

    - by Tom K
    My customer has his own graphics designer he wants to use to style his web application we're building in ASP.NET MVC 4. Our solution is in Bitbucket, but if he can't run it what choices do we have? I doubt he uses Visual Studio 2012. One idea is for us to publish to our solution to a file system, send it to him, have him create a local IIS website on his machine (assuming he isn't using a Mac). Mocking data or pointing to a test SQL in Azure isn't a problem. Then he can make changes to .css and .cshtml files. Will this even work? The point is that he needs to be able to test his changes. I know he can modify the views and just check-in. But he needs to deliver a working design. So it seems inefficient. The graphics designer will have access to our test site so he can see how it works, what data we have and fields. Another idea is for him to build a static mock site using just HTML/CSS. Later I'd integrate his styles into customer's solution, split his html into partial views which we use and add Razor syntax. Again, we'd like to leverage graphics designer for all of this. Is there a best practice documented around this subject? How do other teams deal with this situation?

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  • Running ASP.NET Webforms and ASP.NET MVC side by side

    - by rajbk
    One of the nice things about ASP.NET MVC and its older brother ASP.NET WebForms is that they are both built on top of the ASP.NET runtime environment. The advantage of this is that, you can still run them side by side even though MVC and WebForms are different frameworks. Another point to note is that with the release of the ASP.NET routing in .NET 3.5 SP1, we are able to create SEO friendly URLs that do not map to specific files on disk. The routing is part of the core runtime environment and therefore can be used by both WebForms and MVC. To run both frameworks side by side, we could easily create a separate folder in your MVC project for all our WebForm files and be good to go. What this post shows you instead, is how to have an MVC application with WebForm pages  that both use a common master page and common routing for SEO friendly URLs.  A sample project that shows WebForms and MVC running side by side is attached at the bottom of this post. So why would we want to run WebForms and MVC in the same project?  WebForms come with a lot of nice server controls that provide a lot of functionality. One example is the ReportViewer control. Using this control and client report definition files (RDLC), we can create rich interactive reports (with charting controls). I show you how to use the ReportViewer control in a WebForm project here :  Creating an ASP.NET report using Visual Studio 2010. We can create even more advanced reports by using SQL reporting services that can also be rendered by the ReportViewer control. Now, consider the sample MVC application I blogged about called ASP.NET MVC Paging/Sorting/Filtering using the MVCContrib Grid and Pager. Assume you were given the requirement to add a UI to the MVC application where users could interact with a report and be given the option to export the report to Excel, PDF or Word. How do you go about doing it?   This is a perfect scenario to use the ReportViewer control and RDLCs. As you saw in the post on creating the ASP.NET report, the ReportViewer control is a Web Control and is designed to be run in a WebForm project with dependencies on, amongst others, a ScriptManager control and the beloved Viewstate.  Since MVC and WebForm both run under the same runtime, the easiest thing to is to add the WebForm application files (index.aspx, rdlc, related class files) into our MVC project. You can copy the files over from the WebForm project into the MVC project. Create a new folder in our MVC application called CommonReports. Add the index.aspx and rdlc file from the Webform project   Right click on the Index.aspx file and convert it to a web application. This will add the index.aspx.designer.cs file (this step is not required if you are manually adding a WebForm aspx file into the MVC project).    Verify that all the type names for the ObjectDataSources in code behind to point to the correct ProductRepository and fix any compiler errors. Right click on Index.aspx and select “View in browser”. You should see a screen like the one below:   There are two issues with our page. It does not use our site master page and the URL is not SEO friendly. Common Master Page The easiest way to use master pages with both MVC and WebForm pages is to have a common master page that each inherits from as shown below. The reason for this is most WebForm controls require them to be inside a Form control and require ControlState or ViewState. ViewMasterPages used in MVC, on the other hand, are designed to be used with content pages that derive from ViewPage with Viewstate turned off. By having a separate master page for MVC and WebForm that inherit from the Root master page,, we can set properties that are specific to each. For example, in the Webform master, we can turn on ViewState, add a form tag etc. Another point worth noting is that if you set a WebForm page to use a MVC site master page, you may run into errors like the following: A ViewMasterPage can be used only with content pages that derive from ViewPage or ViewPage<TViewItem> or Control 'MainContent_MyButton' of type 'Button' must be placed inside a form tag with runat=server. Since the ViewMasterPage inherits from MasterPage as seen below, we make our Root.master inherit from MasterPage, MVC.master inherit from ViewMasterPage and Webform.master inherits from MasterPage. We define the attributes on the master pages like so: Root.master <%@ Master Inherits="System.Web.UI.MasterPage"  … %> MVC.master <%@ Master MasterPageFile="~/Views/Shared/Root.Master" Inherits="System.Web.Mvc.ViewMasterPage" … %> WebForm.master <%@ Master MasterPageFile="~/Views/Shared/Root.Master" Inherits="NorthwindSales.Views.Shared.Webform" %> Code behind: public partial class Webform : System.Web.UI.MasterPage {} We make changes to our reports aspx file to use the Webform.master. See the source of the master pages in the sample project for a better understanding of how they are connected. SEO friendly links We want to create SEO friendly links that point to our report. A request to /Reports/Products should render the report located in ~/CommonReports/Products.aspx. Simillarly to support future reports, a request to /Reports/Sales should render a report in ~/CommonReports/Sales.aspx. Lets start by renaming our index.aspx file to Products.aspx to be consistent with our routing criteria above. As mentioned earlier, since routing is part of the core runtime environment, we ca easily create a custom route for our reports by adding an entry in Global.asax. public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}");   //Custom route for reports routes.MapPageRoute( "ReportRoute", // Route name "Reports/{reportname}", // URL "~/CommonReports/{reportname}.aspx" // File );     routes.MapRoute( "Default", // Route name "{controller}/{action}/{id}", // URL with parameters new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults ); } With our custom route in place, a request to Reports/Employees will render the page at ~/CommonReports/Employees.aspx. We make this custom route the first entry since the routing system walks the table from top to bottom, and the first route to match wins. Note that it is highly recommended that you write unit tests for your routes to ensure that the mappings you defined are correct. Common Menu Structure The master page in our original MVC project had a menu structure like so: <ul id="menu"> <li> <%=Html.ActionLink("Home", "Index", "Home") %></li> <li> <%=Html.ActionLink("Products", "Index", "Products") %></li> <li> <%=Html.ActionLink("Help", "Help", "Home") %></li> </ul> We want this menu structure to be common to all pages/views and hence should reside in Root.master. Unfortunately the Html.ActionLink helpers will not work since Root.master inherits from MasterPage which does not have the helper methods available. The quickest way to resolve this issue is to use RouteUrl expressions. Using  RouteUrl expressions, we can programmatically generate URLs that are based on route definitions. By specifying parameter values and a route name if required, we get back a URL string that corresponds to a matching route. We move our menu structure to Root.master and change it to use RouteUrl expressions: <ul id="menu"> <li> <asp:HyperLink ID="hypHome" runat="server" NavigateUrl="<%$RouteUrl:routename=default,controller=home,action=index%>">Home</asp:HyperLink></li> <li> <asp:HyperLink ID="hypProducts" runat="server" NavigateUrl="<%$RouteUrl:routename=default,controller=products,action=index%>">Products</asp:HyperLink></li> <li> <asp:HyperLink ID="hypReport" runat="server" NavigateUrl="<%$RouteUrl:routename=ReportRoute,reportname=products%>">Product Report</asp:HyperLink></li> <li> <asp:HyperLink ID="hypHelp" runat="server" NavigateUrl="<%$RouteUrl:routename=default,controller=home,action=help%>">Help</asp:HyperLink></li> </ul> We are done adding the common navigation to our application. The application now uses a common theme, routing and navigation structure. Conclusion We have seen how to do the following through this post Add a WebForm page from a WebForm project to an existing ASP.NET MVC application Use a common master page for both WebForm and MVC pages Use routing for SEO friendly links Use a common menu structure for both WebForm and MVC. The sample project is attached below. Version: VS 2010 RTM Remember to change your connection string to point to your Northwind database NorthwindSalesMVCWebform.zip

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  • Database version control resources

    - by Wes McClure
    In the process of creating my own DB VCS tool tsqlmigrations.codeplex.com I ran into several good resources to help guide me along the way in reviewing existing offerings and in concepts that would be needed in a good DB VCS.  This is my list of helpful links that others can use to understand some of the concepts and some of the tools in existence.  In the next few posts I will try to explain how I used these to create TSqlMigrations.   Blogs entries Three rules for database work - K. Scott Allen http://odetocode.com/blogs/scott/archive/2008/01/30/three-rules-for-database-work.aspx Versioning databases - the baseline http://odetocode.com/blogs/scott/archive/2008/01/31/versioning-databases-the-baseline.aspx Versioning databases - change scripts http://odetocode.com/blogs/scott/archive/2008/02/02/versioning-databases-change-scripts.aspx Versioning databases - views, stored procedures and the like http://odetocode.com/blogs/scott/archive/2008/02/02/versioning-databases-views-stored-procedures-and-the-like.aspx Versioning databases - branching and merging http://odetocode.com/blogs/scott/archive/2008/02/03/versioning-databases-branching-and-merging.aspx Evolutionary Database Design - Martin Fowler http://martinfowler.com/articles/evodb.html Are database migration frameworks worth the effort? - Good challenges http://www.ridgway.co.za/archive/2009/01/03/are-database-migration-frameworks-worth-the-effort.aspx Continuous Integration (in general) http://martinfowler.com/articles/continuousIntegration.html http://martinfowler.com/articles/originalContinuousIntegration.html Is Your Database Under Version Control? http://www.codinghorror.com/blog/archives/000743.html 11 Tools for Database Versioning http://secretgeek.net/dbcontrol.asp How to do database source control and builds http://mikehadlow.blogspot.com/2006/09/how-to-do-database-source-control-and.html .Net Database Migration Tool Roundup http://flux88.com/blog/net-database-migration-tool-roundup/ Books Book Description Refactoring Databases: Evolutionary Database Design Martin Fowler signature series on refactoring databases. Book site: http://databaserefactoring.com/ Recipes for Continuous Database Integration: Evolutionary Database Development (Digital Short Cut) A good question/answer layout of common problems and solutions with database version control. http://www.informit.com/store/product.aspx?isbn=032150206X

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  • Entity Framework v1 &ndash; tips and Tricks Part 3

    - by Rohit Gupta
    General Tips on Entity Framework v1 & Linq to Entities: ToTraceString() If you need to know the underlying SQL that the EF generates for a Linq To Entities query, then use the ToTraceString() method of the ObjectQuery class. (or use LINQPAD) Note that you need to cast the LINQToEntities query to ObjectQuery before calling TotraceString() as follows: 1: string efSQL = ((ObjectQuery)from c in ctx.Contact 2: where c.Address.Any(a => a.CountryRegion == "US") 3: select c.ContactID).ToTraceString(); ================================================================================ MARS or MultipleActiveResultSet When you create a EDM Model (EDMX file) from the database using Visual Studio, it generates a connection string with the same name as the name of the EntityContainer in CSDL. In the ConnectionString so generated it sets the MultipleActiveResultSet attribute to true by default. So if you are running the following query then it streams multiple readers over the same connection: 1: using (BAEntities context = new BAEntities()) 2: { 3: var cons = 4: from con in context.Contacts 5: where con.FirstName == "Jose" 6: select con; 7: foreach (var c in cons) 8: { 9: if (c.AddDate < new System.DateTime(2007, 1, 1)) 10: { 11: c.Addresses.Load(); 12: } 13: } 14: } ================================================================================= Explicitly opening and closing EntityConnection When you call ToList() or foreach on a LINQToEntities query the EF automatically closes the connection after all the records from the query have been consumed. Thus if you need to run many LINQToEntities queries over the same connection then explicitly open and close the connection as follows: 1: using (BAEntities context = new BAEntities()) 2: { 3: context.Connection.Open(); 4: var cons = from con in context.Contacts where con.FirstName == "Jose" 5: select con; 6: var conList = cons.ToList(); 7: var allCustomers = from con in context.Contacts.OfType<Customer>() 8: select con; 9: var allcustList = allCustomers.ToList(); 10: context.Connection.Close(); 11: } ====================================================================== Dispose ObjectContext only if required After you retrieve entities using the ObjectContext and you are not explicitly disposing the ObjectContext then insure that your code does consume all the records from the LinqToEntities query by calling .ToList() or foreach statement, otherwise the the database connection will remain open and will be closed by the garbage collector when it gets to dispose the ObjectContext. Secondly if you are making updates to the entities retrieved using LinqToEntities then insure that you dont inadverdently dispose of the ObjectContext after the entities are retrieved and before calling .SaveChanges() since you need the SAME ObjectContext to keep track of changes made to the Entities (by using ObjectStateEntry objects). So if you do need to explicitly dispose of the ObjectContext do so only after calling SaveChanges() and only if you dont need to change track the entities retrieved any further. ======================================================================= SQL InjectionAttacks under control with EFv1 LinqToEntities and LinqToSQL queries are parameterized before they are sent to the DB hence they are not vulnerable to SQL Injection attacks. EntitySQL may be slightly vulnerable to attacks since it does not use parameterized queries. However since the EntitySQL demands that the query be valid Entity SQL syntax and valid native SQL syntax at the same time. So the only way one can do a SQLInjection Attack is by knowing the SSDL of the EDM Model and be able to write the correct EntitySQL (note one cannot append regular SQL since then the query wont be a valid EntitySQL syntax) and append it to a parameter. ====================================================================== Improving Performance You can convert the EntitySets and AssociationSets in a EDM Model into precompiled Views using the edmgen utility. for e.g. the Customer Entity can be converted into a precompiled view using edmgen and all LinqToEntities query against the contaxt.Customer EntitySet will use the precompiled View instead of the EntitySet itself (the same being true for relationships (EntityReference & EntityCollections of a Entity)). The advantage being that when using precompiled views the performance will be much better. The syntax for generating precompiled views for a existing EF project is : edmgen /mode:ViewGeneration /inssdl:BAModel.ssdl /incsdl:BAModel.csdl /inmsl:BAModel.msl /p:Chap14.csproj Note that this will only generate precompiled views for EntitySets and Associations and not for existing LinqToEntities queries in the project.(for that use CompiledQuery.Compile<>) Secondly if you have a LinqToEntities query that you need to run multiple times, then one should precompile the query using CompiledQuery.Compile method. The CompiledQuery.Compile<> method accepts a lamda expression as a parameter, which denotes the LinqToEntities query  that you need to precompile. The following is a example of a lamda that we can pass into the CompiledQuery.Compile() method 1: Expression<Func<BAEntities, string, IQueryable<Customer>>> expr = (BAEntities ctx1, string loc) => 2: from c in ctx1.Contacts.OfType<Customer>() 3: where c.Reservations.Any(r => r.Trip.Destination.DestinationName == loc) 4: select c; Then we call the Compile Query as follows: 1: var query = CompiledQuery.Compile<BAEntities, string, IQueryable<Customer>>(expr); 2:  3: using (BAEntities ctx = new BAEntities()) 4: { 5: var loc = "Malta"; 6: IQueryable<Customer> custs = query.Invoke(ctx, loc); 7: var custlist = custs.ToList(); 8: foreach (var item in custlist) 9: { 10: Console.WriteLine(item.FullName); 11: } 12: } Note that if you created a ObjectQuery or a Enitity SQL query instead of the LINQToEntities query, you dont need precompilation for e.g. 1: An Example of EntitySQL query : 2: string esql = "SELECT VALUE c from Contacts AS c where c is of(BAGA.Customer) and c.LastName = 'Gupta'"; 3: ObjectQuery<Customer> custs = CreateQuery<Customer>(esql); 1: An Example of ObjectQuery built using ObjectBuilder methods: 2: from c in Contacts.OfType<Customer>().Where("it.LastName == 'Gupta'") 3: select c This is since the Query plan is cached and thus the performance improves a bit, however since the ObjectQuery or EntitySQL query still needs to materialize the results into Entities hence it will take the same amount of performance hit as with LinqToEntities. However note that not ALL EntitySQL based or QueryBuilder based ObjectQuery plans are cached. So if you are in doubt always create a LinqToEntities compiled query and use that instead ============================================================ GetObjectStateEntry Versus GetObjectByKey We can get to the Entity being referenced by the ObjectStateEntry via its Entity property and there are helper methods in the ObjectStateManager (osm.TryGetObjectStateEntry) to get the ObjectStateEntry for a entity (for which we know the EntityKey). Similarly The ObjectContext has helper methods to get an Entity i.e. TryGetObjectByKey(). TryGetObjectByKey() uses GetObjectStateEntry method under the covers to find the object, however One important difference between these 2 methods is that TryGetObjectByKey queries the database if it is unable to find the object in the context, whereas TryGetObjectStateEntry only looks in the context for existing entries. It will not make a trip to the database ============================================================= POCO objects with EFv1: To create POCO objects that can be used with EFv1. We need to implement 3 key interfaces: IEntityWithKey IEntityWithRelationships IEntityWithChangeTracker Implementing IEntityWithKey is not mandatory, but if you dont then we need to explicitly provide values for the EntityKey for various functions (for e.g. the functions needed to implement IEntityWithChangeTracker and IEntityWithRelationships). Implementation of IEntityWithKey involves exposing a property named EntityKey which returns a EntityKey object. Implementation of IEntityWithChangeTracker involves implementing a method named SetChangeTracker since there can be multiple changetrackers (Object Contexts) existing in memory at the same time. 1: public void SetChangeTracker(IEntityChangeTracker changeTracker) 2: { 3: _changeTracker = changeTracker; 4: } Additionally each property in the POCO object needs to notify the changetracker (objContext) that it is updating itself by calling the EntityMemberChanged and EntityMemberChanging methods on the changeTracker. for e.g.: 1: public EntityKey EntityKey 2: { 3: get { return _entityKey; } 4: set 5: { 6: if (_changeTracker != null) 7: { 8: _changeTracker.EntityMemberChanging("EntityKey"); 9: _entityKey = value; 10: _changeTracker.EntityMemberChanged("EntityKey"); 11: } 12: else 13: _entityKey = value; 14: } 15: } 16: ===================== Custom Property ==================================== 17:  18: [EdmScalarPropertyAttribute(IsNullable = false)] 19: public System.DateTime OrderDate 20: { 21: get { return _orderDate; } 22: set 23: { 24: if (_changeTracker != null) 25: { 26: _changeTracker.EntityMemberChanging("OrderDate"); 27: _orderDate = value; 28: _changeTracker.EntityMemberChanged("OrderDate"); 29: } 30: else 31: _orderDate = value; 32: } 33: } Finally you also need to create the EntityState property as follows: 1: public EntityState EntityState 2: { 3: get { return _changeTracker.EntityState; } 4: } The IEntityWithRelationships involves creating a property that returns RelationshipManager object: 1: public RelationshipManager RelationshipManager 2: { 3: get 4: { 5: if (_relManager == null) 6: _relManager = RelationshipManager.Create(this); 7: return _relManager; 8: } 9: } ============================================================ Tip : ProviderManifestToken – change EDMX File to use SQL 2008 instead of SQL 2005 To use with SQL Server 2008, edit the EDMX file (the raw XML) changing the ProviderManifestToken in the SSDL attributes from "2005" to "2008" ============================================================= With EFv1 we cannot use Structs to replace a anonymous Type while doing projections in a LINQ to Entities query. While the same is supported with LINQToSQL, it is not with LinqToEntities. For e.g. the following is not supported with LinqToEntities since only parameterless constructors and initializers are supported in LINQ to Entities. (the same works with LINQToSQL) 1: public struct CompanyInfo 2: { 3: public int ID { get; set; } 4: public string Name { get; set; } 5: } 6: var companies = (from c in dc.Companies 7: where c.CompanyIcon == null 8: select new CompanyInfo { Name = c.CompanyName, ID = c.CompanyId }).ToList(); ;

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  • Separation of development responsibilities in a new project

    - by dreza
    We have very recently started a new project (MVC 3.0) and some of our early discussion has been around how the work and development will be split amongst the team members to ensure we get the least amount of overlap of work and so help make it a bit easier for each developer to get on and do their work. The project is expected to take about 6 months - 1 year (although not all developers are likely to be on and might filter off towards the end), Our team is going to be small so this will help out a bit I believe. The team will essentially consist of: 3 x developers (All different levels i.e. more senior, intermediate and junior) 1 x project manager / product owner / tester An external company responsbile for doing our design work General project/development decisions so far have included: Develop in an Agile way using SCRUM techniques (We are still very much learning this approach as a company) Use MVVM archectecture Use Ninject and DI where possible Attempt to use as TDD as much as possible to drive development. Keep our controllers as skinny as possible Keep our views as simple as possible During our discussions two approaches have been broached as too how to seperate the workload given our objectives outlined above. OPTION 1: A framework seperation where each person is responsible for conceptual areas with overlap and discussion primarily in the integration areas. The integration areas would the responsibily of both developers as required. View prototypes (**Graphic designer**) | - Mockups | Views (Razor and view helpers etc) & Javascript (**Developer 1**) | - View models (Integration point) | Controllers and Application logic (**Developer 2**) | - Models (Integration point) | Domain model and persistence (**Developer 3**) OPTION 2: A more task orientated approach where each person is responsible for the completion of the entire task (story) from view - controller - model. QUESTION: For those who have worked in small teams developing MVC projects how have you managed the workload distribution in this situation. I can't imagine the junior would be responsible for building parts of the underlying architecture so would given them responsibility for the view make sense considering we are trying to keep it simple?

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  • Entity Framework with large systems - how to divide models?

    - by jkohlhepp
    I'm working with a SQL Server database with 1000+ tables, another few hundred views, and several thousand stored procedures. We are looking to start using Entity Framework for our newer projects, and we are working on our strategy for doing so. The thing I'm hung up on is how best to split the tables into different models (EDMX or DbContext if we go code first). I can think of a few strategies right off the bat: Split by schema We have our tables split across probably a dozen schemas. We could do one model per schema. This isn't perfect, though, because dbo still ends up being very large, with 500+ tables / views. Another problem is that certain units of work will end up having to do transactions that span multiple models, which adds to complexity, although I assume EF makes this fairly straightforward. Split by intent Instead of worrying about schemas, split the models by intent. So we'll have different models for each application, or project, or module, or screen, depending on how granular we want to get. The problem I see with this is that there are certain tables that inevitably have to be used in every case, such as User or AuditHistory. Do we add those to every model (violates DRY I think), or are those in a separate model that is used by every project? Don't split at all - one giant model This is obviously simple from a development perspective but from my research and my intuition this seems like it could perform terribly, both at design time, compile time, and possibly run time. What is the best practice for using EF against such a large database? Specifically what strategies do people use in designing models against this volume of DB objects? Are there options that I'm not thinking of that work better than what I have above? Also, is this a problem in other ORMs such as NHibernate? If so have they come up with any better solutions than EF?

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