Query in DB casts to bigint unnecessarily

Question

I have a query in linq that looks like:

IEnumerable<long> ids = Enumerable.Range(1,5).Select(x => (long)x).ToList();
    this.tableA.Where(x => ids.Contains(x.id))
    .Take(1000)
    .ToList();

The resulting query casts each of the values in IEnumerable<long> ids to bigint and I don't understand why, My tableA Model in my code uses long for the id and the table in the DB uses bigint for the id

This is the query:

SELECT TOP (1000) 
    [Extent1].[id] AS [id]
    FROM [dbo].[tableA] AS [Extent1]
    WHERE [Extent1].[id] IN (cast(1 as bigint), cast(2 as bigint), cast(3 as bigint), cast(4 as bigint), cast(5 as bigint))

Anyone knows why this casting happens?

Answer 1

According to Entity Framework Core Tutorials at Conventions in Entity Framework Core, long is considered and dealt as bigint due to both being a Int64 type. If you want to use sql data type int you should declare your properties as int in c#. This is the case for other ORM's as well.

Answer 2

If you think simply, It is the direct convertion from SQL to C#. SQL bigint directly convert to System.Int64 in C#.

In C#:

int = System.Int32
long = System.Int64
short = System.Int16

Please check tke SQL server data type mapping documentation: https://docs.microsoft.com/en-us/sql/connect/ado-net/sql-server-data-type-mappings?view=sql-server-ver15

Therefore, you will get long type in the ORM and bigint in the SQL table.