Using Entity Framework to create or update database(Migration)

Once you define your object model in C# or VB, you can push the object to your database. Most of the case entity framework will handle the update automatically. And you dont even need to write a SQL code.
This development method also commonly know as "Code First" in Entity Framework.

However I searched numbers of blog posts and found not a lot of them mention the command to generate and update database. And here are the procedures to create or update your databases:

1. Develop your object in visual studio
2. Make sure your connection is correct and the account have permission to crate and update
3. Open package manager console (view > other windows >  package manager console)
4. Enable automatic migration if you haven't by "PM> Enable-Migrations -EnableAutomaticMigrations"
5. Update database command "PM> Update-Database"

Thanks Travis in providing these procedure.

Update status in CRM 2011

Here is the code to update a recode via CRM context object:

CRMContext.Execute(new SetStateRequest
            {
                EntityMoniker = new EntityReference
                {
                    Id = new Guid(""),
                    LogicalName = "" //Entity Name
                },
                State = new OptionSetValue(1), //get the value
                Status = new OptionSetValue(1)
            }
            );

Select top N from group

This is a simple SQL select query to illustrate how to select top (or bottom) N from each group.

Here is the data structure

Table 1: product

Prodcut_ID	Product_Name
1	Apple
2	Orange
3	Banana
4	Mango

Table 2: Review

Review_ID	Product_FK	Score
1	1	9
2	4	3
3	3	8
4	2	9
5	2	7
6	3	6
7	2	8
8	1	6
9	2	6
10	3	7
11	4	8
12	4	5

SQL query to select top review score from each product

SELECT P.Product_Name, R.Score AS 'Top Score' FROM Product AS P

LEFT JOIN Review AS R ON R.Product_FK = P.Prodcut_ID

AND R.Review_ID =

      (SELECT TOP 1 R2.Review_ID FROM Review AS R2

      WHERE R2.Product_FK = P.Prodcut_ID

      ORDER BY R2.Score DESC)

Here is the select result:

Product_Name	Top Score
Apple	9
Orange	9
Banana	8
Mango	8

You can also use the same query to get average or do other calculations

The context is not currently tracking the entity

I encountered this error when I deploy a plug-in to CRM online environment. I tested the same plug-in in on premises environment and it works without any error.

The plugin read and write to entity A and entity B (they have no relationships). The plug-in is triggered when entity A records are created and it retrieve all records from entity B and process them.

The error was thrown when it tries to save changes to entity B, with this error message: The context is not currently tracking the <<entity B>> entity

It suggested the services context does not track <<entity B>> in the scope. I researched this topic and found out I need to use OrganizationServiceContext.Attach Method. However when I use this method it returns with this error: The context is already tracking the <<entity B>> entity. :(

And did more research and found that it actually need to detach the object ( OrganizationServiceContext.Detach Method) before it can be attached.

This makes no sense to me but this is the work around.

CRM 2011 Plug-in error: Object reference not set to an instance of an object.

Problem/Error:

When I create an instance of object from the sdk generated code by using the default constructor like:

email.regardingobjectid = new CrmEntityReference();

I will find it return a null object:

This is not the result I wanted because the object does not have correct structure and when I try to assign a value to the object (in this case is regardingobjectid) it will throw a NullReferenceException error like this:

Solution

The solution is relatively simple by using a different constructor and it will give a correct object:

email.regardingobjectid = new CrmEntityReference("contact", contact.contactid);

CRM Email router time out

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