VistaDB	SQL Server	SQL CE	.NET System
BigInt	BigInt	BigInt	Int64
Bit	Bit	Bit	Byte
Char	Char	-	String
DateTime	DateTime	DateTime	DateTime
Decimal*	Decimal	Decimal*	Decimal*
Float	Float	Float	Double
Identity Fields	Identity Fields	Identity Fields	-
VarBinary (Max)	Image	-	Byte[]
Int	Int	Int	Int32
Money	Money	Money	Decimal
NChar	NChar	NChar	String
NVarchar (Max)	NText	NText (500Mb)	String
NVarchar	NVarchar	NVarchar	String
Real	Real	Real	Single
SmallDateTime	SmallDateTime	-	Int16
SmallInt	SmallInt	SmallInt	Int16
SmallMoney	SmallMoney	-	Decimal
Varchar (Max)	Text	-	String
Timestamp	Timestamp	Timestamp	Int64
TinyInt	TinyInt	TinyInt	Byte
UniqueIdentifier	UniqueIdentifier	UniqueIdentifier	Guid
VarBinary	VarBinary	VarBinary(4000)	Byte[]
VarChar	VarChar	-	String
-	XML	-	-
-	RowVersion	RowVersion	-
DateTime2	DateTime2		DateTime2
Date	Date		DateTime
Time	Time		Timespan
DateTimeOffset	DateTimeOffset		DateTimeOffset
TImespan	Timespan		Timespan
-	Geography	-	(class)
-	Geometry	-	(class)

Decimal data types are different in .Net than SQL Server.

.NET decimals do not store the same resolution and can't cover the same range as the SqlDecimal type.

VistaDB uses .NET managed decimals for storage. Precision is not actually enforced in .NET other than at creation time. .NET truncates the values and stores them in a decimal. There is no way to preserve those values in a .NET operation (if you do any operation to a decimal in .NET it is rounded and presented as a system decimal afterwards).

One alternative is to store the values as strings, and parse back the string to get the effectivescale and effectiveprecision on a per value stored basis. See this Stack Overflow post for other people talking about the issue as well (StackOverflow question on Precision and Scale).

Another option if you need that level of scale and precision is to store the levels you need in multiple columns and then recalculate actual decimal values (keeping in mind that .NET will round them on you with your next operation).