Paging with Entity Framework 7 and SQL Server 2008

问题

I'm trying to use paging (that is .Skip(...).Take(...) in Entity Framework 7. It works OK with Microsoft SQL Server 2012 and 2014, but fails with the following error on SQL Server 2008:

System.Data.SqlClient.SqlException (0x80131904): Incorrect syntax near 'OFFSET'. Invalid usage of the option NEXT in the FETCH statement.

I've figured out that it is a breaking change in EF version 6.1.2 (http://erikej.blogspot.com/2014/12/a-breaking-change-in-entity-framework.html). But the fix is to modify EDMX file setting ProviderManifestToken attribute to "2008".

The problem is that EF7 currently only supports code-first scenario, thus there is no any EDMX out there. The question is: how to configure ASP.NET 5 website with Entity Framework 7 to use fallback pagination approach for SQL Server older than 2012?

回答1:

I encountered this problem myself using EF 7 and sql server 2008. Fortunately in the latest rc1 version of EF 7 you can solve this by using .UseRowNumberForPaging() as shown in this example:

services.AddEntityFramework()
  .AddSqlServer()
  .AddDbContext<YourDbContext>(options =>
     options.UseSqlServer(configuration["Data:DefaultConnection:ConnectionString"])
                    // this is needed unless you are on mssql 2012 or higher
                    .UseRowNumberForPaging()
                );

回答2:

If you use Edmx file, you must open the edmx file using XML Editor and change

ProviderManifestToken="2012" ==> ProviderManifestToken="2008"

in line 7.

Please take a look at this blog post for more information: http://erikej.blogspot.com.tr/2014/12/a-breaking-change-in-entity-framework.html

回答3:

It's broken in RC 1. Gotta wait to get RC 2.

https://github.com/aspnet/EntityFramework/issues/4616

回答4:

MyDbConnectionString is Connection string from any source

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
    optionsBuilder.UseSqlServer(_config["MyDbConnectionString"], 
                options=>
                {
                    options.UseRowNumberForPaging();
                });
}

UseRowNumberForPaging() solved issue in any case except for edmx file scenario.

回答5:

You need to use something like this :

var MinPageRank = (pageIndex - 1) * pageSize + 1;
var MaxPageRank = (pageIndex * pageSize);

var person = _context.Person.FromSql($"SELECT * FROM (SELECT [RANK] = ROW_NUMBER() OVER (ORDER BY Surname),* FROM Person) A WHERE A.[RANK] BETWEEN {MinPageRank} AND {MaxPageRank}").ToList();

IQueryable<Person> PersonIQ = from s in person.AsQueryable() select s;
Person = await PaginatedList<Person>.CreateAsync(PersonIQ .AsNoTracking(), pageIndex ?? 1, pageSize, sourceFull);

回答6:

Here, just set UseRowNumberForPaging() in ConfigureServices

services.AddDbContext<CallcContext>(options => 
options.UseSqlServer(Configuration.GetConnectionString("Connectionstring"),opt=> { opt.UseRowNumberForPaging(); }));

来源：https://stackoverflow.com/questions/29995502/paging-with-entity-framework-7-and-sql-server-2008