String must be exactly one character long.

When you have DBML lINQ entity fields with CHAR data type. you will get an error while retrieve the data.

Solution:
----------
1) go to the DBML entity
2) select field
3) press F4
4) change data type to string from char, where you have DB data type VARCHAR(1)
5) Save

Cannot add an entity with a key that is already in use, LINQ

When you have table with ID coulumn (uniqueidentifier) and default value = (newid()),
than the above error occur.

To Resolve:

1) go to your .DBML file design view
2) go to property of particular columns
3) set "Auto generated Value" = true.

it will add following in DBML file IsDbGenerated="true"

String or Binary Data Would Be Truncated Error, LINQ

Error: String or Binary Data Would Be Truncated.

Desc:
Generally this error occurs when we are trying to inser/update large value in SQL server table that are not fit into columns lenght of table.

In one scenario i experienced the following scenario:

I had the one enum like below:
public enum MyEnum
{ First = 101, Second=102, Sixth=103)

now I was using this enum like MyEnum.First and assigning to the one variable
But when i was trying to insert that entity in database using LINQ i was getting the above error:


After doing debugging, I've to do following changes

var myvar = (int) MyEnum.First;

The above statement will return the 101,

that's it for now.