Insert records using select in LINQ - linq

Question

How can we convert following query to LINQ
INSERT INTO License (PersonID, LicenseState, LicenseNumber, LicenseYear)
SELECT p.PersonID,
s.LicenseState,
s.LicenseNumber,
s.LicenseYear
FROM SourceData s
JOIN Person p
ON s.UserID = p.DomainAccountName
WHERE s.isActive = 1

Answer 1

var query = from s in db.SourceData
join p in db.Person on s.UserId equals p.DomainAccountName
where s.IsActive
select new License
{
PersonID = p.PersonID,
LicenseState = s.LicenseState,
LicenseNumber = s.LicenseNumber,
LicenseYear = s.LicenseYear
};
db.Licenses.AddRange(query);
That will actually give you one SQL query, and a bunch of individual SQL INSERTS. Alternately, you could use the Z.EntityFramework.Plus.EFCore nuget package, and use the code
var query = ... (same)...
db.Licenses.InsertFromQuery(query);
which should use the single SQL statement you posted.
UPDATE: I originally confused the retail/licensed Z.EntityFramework.Extensions.EFCore with the free/open-source Z.EntityFramework.Plus.EFCore package. Code above has been updated.

Answer 2

If you care about performance, you don't have to load anything to the client. It is how EF Core works right now, if you want to insert something - you have to feed ChangeTracker with new records.
I would suggest EF Core extension linq2db.EntityFrameworkCore which generates exactly the same query as in question but via LINQ. Note that I'm one of the creators.
Then you can do the following:
var query =
from s in db.SourceData
join p in db.Person on s.UserId equals p.DomainAccountName
where s.IsActive
select new License
{
PersonID = p.PersonID,
LicenseState = s.LicenseState,
LicenseNumber = s.LicenseNumber,
LicenseYear = s.LicenseYear
};
await query.InsertAsync(db.License.ToLinqToDBTable(), x => x);