WCF Data services remove miliseconds from DateTime when expand

Question

I get some strange behavior, when using WCF Data Services 5.6. In my case, I have table, with 1 column set with Concurrency=Fixed, and this column hold date time field from database, updated each time when row is edited. In case I just retrieve entity -
this column has correct value with milliseconds. But if I do mapping - milliseconds are removed.
Here is a issue at glance :
====================================================================
void Main()
var b = from p in TABLE1 where p.ID == 100 select p;
b.Dump();
Request in this case is : Data.svc/TABLE1(100M) And data returned from service is :
<d:COL1 m:type="Edm.DateTime">2015-02-16T12:13:52.972</d:COL1>
====================================================================
As you can see , here time is returned with milliseconds - .972 In other case :
void Main()
var tmp = from p in TABLE1 where p.ID == 100 select
new TABLE1()
ID=p.ID,
COL1=p.COL1
var a1 = tmp.ToList();
a1.Dump();
Request in this case is : Data.svc/TABLE1(100M)?$select=ID,COL1
<d:COL1 m:type="Edm.DateTime">2015-02-16T12:13:52</d:COL1>
====================================================================
Time is returned without milliseconds.
Does anybody have same problem? May be its a bug in the WCF Data services or in the model?

Answer 1

Ok, seems like I found an answer to this, or at least way to avoid the problem.
First I traced generated SQL from framework, and I see that in first case, im getting SQL
     SELECT ID, COL1 FROM TABLE1
and in second case, I got
     SELECT ID, CAST( COL1 AS DATETIME) FROM TABLE1
which cause the problem.
Then I tried to update EF to version 6, WCF Data services to version 5.6.3,
Oracle ODP to latest one, tried to use Oracle managed driver... no any success.
Then I played little bit with table definition, and I saw that my col1 with type TIMESTAMP in database and DateTime in the model was defined as NOT NULL.
If I remove this from database definition, I got right value with milliseconds.
So , may be this is a bug in Oracle driver, but probably this is a bug in the WCF Data Services. At least I found a way to use concurrency in my case with this solution.