.NET (Core and Framework)

DELETE FROM [table name]
TUNCATE TABLE [table name]

DBCC CHECKIDENT([table name], RESEED, 0)

private bool DeleteOldData()
{
	using (var transaction = BeginTransaction(_database))
	{
		try
		{
			string[] tables = { "NToMMappingTable", "Table1", "Table2", "Table3", "Table4" };
			bool[] alter = { false, true, true, true, true };
			for (int i = 0; i < tables.Length; i++)
			{
				string table = tables[i];
				_database.ExecuteStoreCommand(string.Format("DELETE FROM [{0}]", table));
				if (alter[i])
					_database.ExecuteStoreCommand(
						string.Format("ALTER TABLE [{0}] ALTER COLUMN Id IDENTITY (1,1)", table));
			}
			// Delete old data
			transaction.Commit();
			_database.AcceptAllChanges();
			success = true;
		}
		catch (Exception e)
		{
			transaction.Rollback();
			throw;
		}
	}
}

public static DbTransaction BeginTransaction(ObjectContext context)
{
	if (context.Connection.State != ConnectionState.Open)
	{
		context.Connection.Open();
	}
	return context.Connection.BeginTransaction();
}