decimal - nulls

[Mark]

We have a SQL Server table with a decimal column that is not required.
We're building a .NET application for data entry. If the value is optional,
but a decimal is strongly typed in C# and cannot be assigned a value of
null, what are the best practices for dealing with passing this potentially
null value around in a Decimal C# datatype?

Thanks in advance.

Mark

 

[Marina]

This is more difficult, because a Decimal cannot have a null value - by
default it has a value of 0.

Now, when you are getting a value out of a datatable or datareader, you can
get either a DBNull, or an actual decimal value. The most common class for
these is object - so you could always pass around an object, and then always
have to test whether or not it is a DBNull, or an actual decimal.

SqlDataReader class (if you are using sql server) has a GetSqlDecimal method
which returns a SqlDecimal datatype. This structure is like the Decimal
structure, except it has the concept of a Null value.

 

[Eric Johannsen]

We use DataType.MinValue to represent nulls. We define a constant called
something like Constants.NULL_DECIMAL and give it the value MinValue.

I don't know if that's best practice or not, but it works for us.

Eric

 

[Paul E Collins]

We use DataType.MinValue to represent nulls.
We define a constant called something like
Constants.NULL_DECIMAL and give it the value
MinValue.
I don't know if that's best practice or not, but it
works for us.

Not best practice!
http://info.astrian.net/jargon/terms/h/hidden_flag.html

DataType.MinValue is a valid numeric value in itself, and you would
see some pretty strange behaviour in your program if anybody happened
to use it. SqlDecimal supports nulls and is designed specifically for
this purpose, so why not use it?

P.

 

[Michael S]

We have a SQL Server table with a decimal column that is not required.
We're building a .NET application for data entry. If the value is optional,
but a decimal is strongly typed in C# and cannot be assigned a value of
null, what are the best practices for dealing with passing this potentially
null value around in a Decimal C# datatype?

Thanks in advance.

Mark

You will just love C#2.0 / CIL 2.0 as it sports nullable value types. They
are very useful.
As of now you are stuck using the bloated sql datatypes.

- Michael S