Multiple inheritance of interfaces which are pure abstract classes indeed is not a problem until you need to use the interface implementation in other classes.

Suppose there are two interfaces, the implementation of which will be used in other classes.

The namespaces conception in C# seems to be exhaustive and insufficient at the same time compared with a strong module notation in Oberon-2 and even with a modular programming approaches in Free Pascal/Delphi.

Why insufficient? You cannot declare constants and functions within namespaces but you should add a class with constant field or static method for it.

Why exhaustive? The using directive with such introduced classes is the source of unexpected errors. Here is an example below.

Firebird doesn't support INSERT BULK command or bcp.exe utility. But the external tables can be a good replacement. Simple example is below.

Check that firebird.conf file allow to create external tables. Write or uncomment line like

ExternalFileAccess = Full

An example of generic implementation of nullable value types in FreePascal (easy to adapt for Delphi).

There are many examples of user defined table functions generating the series of dates(times) between two specified values. Usually, in OLAP you can see a table filled by the date/time series, too. Such table avoid to generate the values "on the fly".

However, in some cases you may be unable to use an UDF or a table. Fortunately, "pure SQL" method still works.

Suppose, the start and finish dates are specified as entry parameters. The transact SQL code below generates the series "moth by month".