Saturday, August 14, 2010

Npgsql 2.0.10 and NpgsqlParameter.Value

Hi all!

As you may already know, Npgsql 2.0.10 is out. Besides the usual batch of bug fixes and enhancements, this release has a new feature which needs more attention as it may give you backward compatibility problems.

What happened?

With this release, we decided to implement a property in NpgsqlParameter which returns provider specific objects, just like SQLClient does.

NpgsqlParameter now features a property called NpgsqlValue. As you may guess, when you use it, you will receive a value whose type is Npgsql specific.

Why this change?

In the past, we had a lot of problems dealing how we would handle values which are specific to Npgsql, like NpgsqlTimestamp from others which are represented in CLR, like DateTime. This situation led to cast exceptions bugs. This was the main motivation for this.

Also, we think that by implementing this we would be giving our users a much consistent way of getting values in CLR type and in Npgsql-specific type. Another benefit is that now Npgsql can behave better inside DataSet and DataRow objects as they use Value property and expect CLR types being returned.

What is the problem and what can I do about it?

The problem lies in the fact that now, NpgsqlParameter.Value returns only CLR types. So, if your code was expecting to receive Npgsql specific types you may need to change your code to either use CLR type or change the call to NpgsqlValue property.

I think the first option is a good one as it will make your code more portable between other providers. If you are using only Npgsql, second option is a better choice as it will allow you to use directly Npgsql specific types.

We would like to hear from you how this modification is working for you.
Please, post your questions and suggestions in our user forums.

Thanks in advance.

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