Expression Tree for .NET DateTime <> Oracle Timestamp like search

Question

I need to know whether I can get a clue or not. I am trying to build an Expression Tree that is evaluated via Entity Framework 6 (LINQ to Entities) via ODP.NET managed driver (current Version) to the appropriate Oracle statement in order to perform filtering. This works perfectly for string <> nvarchar2 datatypes. The output for a Contains search is something like:

Select * 
[...]
FROM "MYSCHEMA"."MYTABLE" "Extent1"
WHERE ("Extent1"."ANVARCHAR2COLUM" LIKE '%givenStrValueToFind%') 

Now I want to get the same result for a DateTime <> Timestamp(6) since this line of sql statement is valid for an oracle query and returns all Dates which contains '08':

select * from "MYSCHEMA"."MYTABLE" where ATIMESTAMP6COLUMN like '%08%';

Since I am new to Expression Trees, I first need to know (after googling alot and tried this an that), whether this is possible before I dig deeper into. And if so, how could this be accomplished best? Since there is no Contains Method defined for DateTime and DateTime? Maybe providing Extension methods? And I dont want to execude queries directly against database.

Any hints would be nice to 'unhook' the given database datatype perhaps... Thx.

Answer 1

For EF 6 you can use :

ctx.MYTABLE.Where(x=>x.ATIMESTAMP6COLUMN.ToString().Contains("08")).ToList();

which translates to

SELECT 
[Extent1].[some property name] AS [some property name], 
[Extent1].[ATIMESTAMP6COLUMN] AS [ATIMESTAMP6COLUMN], 
.
.
.
FROM [dbo].[MYTABLE] AS [Extent1]
WHERE  CAST( [Extent1].[ATIMESTAMP6COLUMN] AS nvarchar(max)) LIKE N'%08%'

As far as what I know all versions of EF does not support string functions but EF 6.x supports this kind of functions(The EF that I tested with is EF 6.1.3, the test is done with sql server localdb as DBMS).