EF 4.1 RTW Change to Default MaxLength in Code First

re: EF 4.1 RTW Change to Default MaxLength in Code First

David Nelson — Mon, 25 Apr 2011 18:03:33 GMT

As Jon Miller said, varchar(max) columns cannot be indexed. There are also known performance issues when querying varchar(max) columns: there is additional overhead both at the server level and at the TDS protocol level (used by the SQL native client). Using a constant number (e.g. varchar(4000)) would be better.

re: EF 4.1 RTW Change to Default MaxLength in Code First

Leniel Macaferi — Thu, 21 Apr 2011 15:15:37 GMT

Hi,

I think I have a bug for you in respect to the Image data type of SQL CE and Entity Framework 4.1. Take a look at the question I posted at StackOverflow:

stackoverflow.com/.../114029

I solved the problem using the 1st approach described in this post.

Thanks,

Leniel

re: EF 4.1 RTW Change to Default MaxLength in Code First

EF Code First and Concurrency — Mon, 11 Apr 2011 05:56:59 GMT

Hi,

Today, I realised that when I issued the command Submitchanges(), the EF code first wont just update the table it's supposed to be, but also does a cascade update across the foreign key tables too.

1. Why does it do that?

2. Is there any way to prevent that? cause it's causing Optimistic Concurrency Exception in my application.

Thanks,

Sam

re: EF 4.1 RTW Change to Default MaxLength in Code First

Can not write seed（） in database — Mon, 11 Apr 2011 00:28:09 GMT

After update EF4.1，Can not write data in database。why？

-----------------------------------------------------------------------------------------------------------------------------from china

如题：升级到EF4.1 RC 后 seed（）方法里面的数据无法写入到数据库中

我的测试项目升级到EF4.1 RC 后 seed（）方法里面的数据无法写入到数据库中。大师们有没有类似的问题啊：

DBInitializer代码----：

1 public class DBInitializer : DropCreateDatabaseIfModelChanges<ConferenceMSEntitiesContext>

2 {

3 protected override void Seed(ConferenceMSEntitiesContext context)

4 {

5 var de = new List<Department> {

6 new Department{

7 Name="小庙",

8 DepartmentTypeID=1

9 },

10 new Department{

11 Name="经济局",

12 DepartmentTypeID=3

13 },

15 new Department{

16 Name="发改局",

17 DepartmentTypeID=3,

19 }

21 };

25 de.ForEach(d => context.Departments.Add(d));

32 }

34 }

35 }

以上代码最后不论是否添加 base.Seed(context); 和 context.SaveChanges(); 这两行代码，都无法把数据写进数据库。

Application_Start-----------------

1 protected void Application_Start()

2 {

4 System.Data.Entity.Database.SetInitializer<ConferenceMSEntitiesContext>(new DBInitializer());

6 AreaRegistration.RegisterAllAreas();

8 RegisterGlobalFilters(GlobalFilters.Filters);

9 RegisterRoutes(RouteTable.Routes);

10 }

re: EF 4.1 RTW Change to Default MaxLength in Code First

Richard — Wed, 06 Apr 2011 11:46:40 GMT

What about third-party providers? For example, MySql doesn't have a varchar(MAX) type, but presumably won't use the SQL Compact convention. Since you've removed the ability to add custom conventions for code-first, how will EF4.1 handle this?

re: EF 4.1 RTW Change to Default MaxLength in Code First

Jon Miller2 — Mon, 04 Apr 2011 14:29:07 GMT

One issue that I see with changing it to MAX is that you can't index those columns. It seems like you should set it to the max value that is allowed for an indexable column. Also, I'm not sure what the performance implications of having it set to MAX would be.

re: EF 4.1 RTW Change to Default MaxLength in Code First

Will — Fri, 01 Apr 2011 23:22:11 GMT

Thanks for the info. That sounds like the best course of action to me. I did not like the arbitrary 128 character default but will probably try to set a default.

re: EF 4.1 RTW Change to Default MaxLength in Code First

Kyralessa — Fri, 01 Apr 2011 16:50:34 GMT

What's the best way to send feedback? I have a scenario that doesn't work in EF, and I'd love to send a description to someone on the product team, but it seems a bit long for a blog comment.

re: EF 4.1 RTW Change to Default MaxLength in Code First

Thijs Kampen — Fri, 01 Apr 2011 08:50:35 GMT

Good news. From this post I understand you are in the fase of fixing bugs. Is it possible to share some news on the bugfixes regarding multilevel TPH inheritance when using abstract classes?

re: EF 4.1 RTW Change to Default MaxLength in Code First

Terrence_ — Thu, 31 Mar 2011 22:17:15 GMT

That solution sounds fine to me.