Mapping SQL Server Data Types to C# Data Types

Data and Databases
1

I’m working on a project where I need to convert database fields to C# properties. Can someone help me understand what C# data types I should use for different SQL Server column types?

I have tables with various column types and I want to make sure I’m using the right C# equivalents when creating my data models. Here are the SQL types I’m dealing with:

Whole Numbers:

bigint
numeric  
bit
smallint
decimal
smallmoney
int
tinyint
money

Decimal Numbers:

float
real

Date/Time Types:

date
datetimeoffset
datetime2
smalldatetime
datetime
time

Text Data:

char
varchar
text

Unicode Text:

nchar
nvarchar
ntext

Binary Data:

binary
varbinary
image

Special Types:

cursor
timestamp
hierarchyid
uniqueidentifier
sql_variant
xml
table

What would be the best C# data type to use for each of these SQL Server types?

2

Working with SQL Server mappings comes down to getting precision right and handling nulls properly. Here’s what I’ve learned: bigint goes to long, int stays int, smallint becomes short, and tinyint maps to byte. Both decimal and numeric should use C#'s decimal type - don’t lose that precision. Money types? Also decimal. Float becomes double, real maps to float. Most date/time stuff uses DateTime, but datetimeoffset needs DateTimeOffset or you’ll lose timezone info. Text types like varchar, nvarchar, char, and nchar all become string. Binary data uses byte arrays. Watch out for uniqueidentifier - that’s Guid in C#. For xml, you can use XmlDocument or string depending on what you’re doing with it. And remember nullable variants when your columns allow nulls.

3

most of em map pretty easy, like bigint to long, varchar/nvarchar = string, and for datetimes just go with DateTime or DateTimeOffset. but watch out for sql_variant (use object) and hierarchyid (needs special care). also, dont forget nullable types if ur db lets nulls!

4

hey! data mapping can be tricky. are u using entity framework or just doing it all by hand? also, how r your sql columns with nulls? if they allow nulls, u might need to use nullable types like int? instead of int. what’s your plan?