问题
In SQL Server we can write data AS Numeric(15,10) .. what will the equivalent of this in C#?
I know that Numeric's equivalent is Decimal but how to represent Numeric(15,10)?
回答1:
There isn't a direct equivalent, in that there are no built-in .NET types which allow you to specify the precision/scale explicitly as far as I'm aware. There's no fixed-point type like NUMERIC.
decimal and double are the common floating point types in .NET, with decimal implementing decimal floating point (like NUMERIC in T-SQL) and double implementing binary floating point behaviour (like FLOAT and REAL in T-SQL). (There's float as well, which is a smaller binary floating point type.)
You should choose between decimal and double based on what values you're going to represent - I typically think of "man-made", artificial values (particularly money) as being appropriate for decimal, and continuous, natural values (such as physical dimensions) as being appropriate for double.
回答2:
Try looking at this site as a guide to the data type mappings. As far as the precision and length, you control that yourself using format specifiers
回答3:
There are two answers depending on two questions:
1) What is something that allows you to specify the precision and scale. Nothing. This seems like your question, but just in case:
2) What is something that allows you to specify a decimal floating point number exactly. This is indeed the Decimal type -- but the point is internal and is set to one of 2^32 positions based on the input number. Not sure why, but only 28 values work, or 2^5 - 4..
So even though .Net allows the Decimal to look like a float, it is very different under the covers and does match the Decimal of SQLServer. Anything not a sum of distinct power of 2 values is an estimation using the normal binary floating point. This means even something such as the number 0.1, has already lost precision. But not with the Decimal type.
来源：https://stackoverflow.com/questions/6771891/what-is-the-equivalent-datatype-of-sql-servers-numeric-in-c-sharp