Skip to main content

Get Entity Framework 6 use NOLOCK in its underneath SELECT statements

First of all... You should NEVER EVER use NOLOCK for each and every SQL Statement. It could compromise the integrity of your data.
It’s like any other query hint a mechanism you should only use when you do something out of the ordinary.
There is no way to tell the EF Provider to render the NoLock hint. If you really need to read uncommitted data you have the following option.
  1. Write your own EntityFramework Provider.
  2. Use a Command Interceptor to modify the statement before it is executed. http://msdn.microsoft.com/en-us/data/dn469464.aspx
  3. Use a TransactionScope with IsolationLevel.ReadUncommited.
I know you said you do not want to use Transactions but it's the only out-of-the box way to read uncommitted data. Also it does not produce much overhead as each statement in SQL Server “implicitly” runs in a transaction.
using (new TransactionScope(
                    TransactionScopeOption.Required, 
                    new TransactionOptions 
                    { 
                         IsolationLevel = IsolationLevel.ReadUncommitted 
                    })) 
{
        using (var db = new MyDbContext()) { 
            // query
        }
}


Ref : https://stackoverflow.com/questions/24684914/get-entity-framework-6-use-nolock-in-its-underneath-select-statements

Comments

  1. SVOctober 17, 2017 at 11:45 PM

    public static IList ToListNolock(this IQueryable query)
    {
    using (TransactionScope scope = new TransactionScope(TransactionScopeOption.Required, new TransactionOptions() { IsolationLevel = IsolationLevel.ReadUncommitted }))
    {
    IList toReturn = query.ToList();
    scope.Complete();
    return toReturn;
    }
    }

    ReplyDelete
  2. SVOctober 17, 2017 at 11:45 PM

    private static TransactionScope _TransactionScope { get { return new TransactionScope(TransactionScopeOption.Required, new TransactionOptions() { IsolationLevel = IsolationLevel.ReadUncommitted }); } }

    public static List ToListNolock(this IEnumerable query)
    {
    using (_TransactionScope) { return Enumerable.ToList(query); }
    }

    public static T FirstOrDefaultNolock(this IEnumerable query)
    {
    using (_TransactionScope) { return Enumerable.FirstOrDefault(query); }
    }

    ReplyDelete

Post a Comment

Popular posts from this blog

Tip/Trick: Fix Common SEO Problems Using the URL Rewrite Extension

Search engine optimization (SEO) is important for any publically facing web-site.  A large % of traffic to sites now comes directly from search engines, and improving your site’s search relevancy will lead to more users visiting your site from search engine queries.  This can directly or indirectly increase the money you make through your site. This blog post covers how you can use the free Microsoft  URL Rewrite Extension  to fix a bunch of common SEO problems that your site might have.  It takes less than 15 minutes (and no code changes) to apply 4 simple  URL Rewrite  rules to your site, and in doing so cause search engines to drive more visitors and traffic to your site.  The techniques below work equally well with both ASP.NET Web Forms and ASP.NET MVC based sites.  They also works with all versions of ASP.NET (and even work with non-ASP.NET content). [In addition to blogging, I am also now using Twitter for quick updates and to sh...
Post a Comment
Read more

ASP.NET MVC - Set custom IIdentity or IPrincipal

Here's how I do it. I decided to use IPrincipal instead of IIdentity because it means I don't have to implement both IIdentity and IPrincipal. Create the interface interface ICustomPrincipal : IPrincipal { int UserId { get ; set ; } string FirstName { get ; set ; } string LastName { get ; set ; } } CustomPrincipal public class CustomPrincipal : ICustomPrincipal { public IIdentity Identity { get ; private set ; } public bool IsInRole ( string role ) { return false ; } public CustomPrincipal ( string email ) { this . Identity = new GenericIdentity ( email ); } public int UserId { get ; set ; } public string FirstName { get ; set ; } public string LastName { get ; set ; } } CustomPrincipalSerializeModel - for serializing custom information into userdata field in FormsAuthenticationTicket object. public class CustomPrincipalSerializeMode...
8 comments
Read more

linq orderby multiple columns dynamically

So, it's been a while, but I thought I take moment and do my annual blog post ;). I've been playing around with  ASP.NET MVC  and the Linq stuff for  NHibernate  recently. I was in need of an OrderBy extension method that could take a SQL-Like OrderBy string and sort a IQueryable<> or IEnumerable<> collection. I wrote up an implementation that worked, but I just wasn't satisfied with its internals (quite a bit of reflection to get the correct type to construct a LambdaExpression, etc) At any rate, I couldn't leave well enough alone, and, after a bit of Googling, I ran across this  StackOverflow  answer about Dynamic LINQ OrderBy . The extension method wasn't exactly what I was looking for, but that ApplyOrder method is slick, and solved the portion of my implementation that was bothering me. So, I though I would post up my version in case anybody finds it useful. It handles the following inputs: list.OrderBy( "SomeProperty" ); list.Ord...
2 comments
Read more