Custom EF Code First Identity Generation - entity-framework-5

Question

Using EntityFramework 5, I have a new database where I need to specify the identity seed on tables to be something other than "1".
With either the modelbuilder, migrations, or otherwise, is there a simple way to change the identity generation for tables to handle this?
At the moment, I'm looking at creating custom sql generated to call during migrations to modify this after the tables are created. A cleaner solution would be to get the CREATE TABLE correct in the first place.

Answer 1

unfortunately i haven't found a way to "add pre-query" before execute query batch
if anybody will find a way to do that - then before execute commit - we could execute sql:
"set identity_inster on"
after
"set identity_inster off"
which is more natural for t-sql

Answer 2

I am working with same problem, for now following plan a have:
initialize customized migration plan by:
Database.SetInitializer(new MigrateDatabaseToLatestVersion());
Check that an entity has to be generated (class
MyInitConfiguration):
protected override void Seed(MyDbContext context)
{
var he = context.Set<MyEntity>();
if (!he.Any(h => h.Id == 0))
{
...place to add code...
Add entity (or several entities) in normal way, but "before execute commit - call external sql script:
he.Add(new MyEntity{ Id = -5, Alias = "system",Title = "System"});
he.Add(new MyEntity{ Id = -4, Alias = "system1",Title = "System1"});
he.Add(new MyEntity{ Id = -3, Alias = "system2",Title = "System2"});
context.Database.ExecuteSqlCommand(
string.Format("DBCC CHECKIDENT ('{2}', RESEED, {0});",-5,"MyTableName")
);
context.Commit();
or following extension i have prepared for DBContext:
public static void UpdateIdentity<T, TKey>(this MyDbContext context, Func<T> data, TKey staticPreviousId, string tableName,string columnName="id")
where T : MyEntity<TKey>
{
var r = data();
context.Database.ExecuteSqlCommand(string.Format("DBCC CHECKIDENT ('{2}', RESEED, {0});", staticPreviousId, r.Id, tableName, columnName));
context.Commit();
}
then just execute:
context.UpdateIdentity(() => myDataSet.Add(new MyEntity{ Id = -5, Alias = "system",Title = "System"}), -5, "myTableName");
context.UpdateIdentity(() => myDataSet.Add(new MyEntity{ Id = 81, Alias = "system",Title = "System"}), 80, "myTableName");