What represents a double in sql server?

Question

I have a couple of properties in C# which are double and I want to store these in a table in SQL Server, but noticed there is no double type, so what is best to use, decimal or float?

This will store latitude and longitude values, so I need the most accurate precision.

Thanks for the responses so far.

Answer 1

You can either use float or real. ‘float’ is used for the newer version of SQL server whereas, ‘real’ is used for the older version of SQL Server.

Float: You can use float or float(53) as their functionalities are the same.

Note: ‘real’ is equal to float(24) but not equal to float/float(53).

• In SQL Server, decimal(x, y) is used only when exact decimal numbers are needed not for the floating-point. But, in C# ‘decimal’ data is used as it’s 128-bit floating-point number. 

• MYSQL doesn’t have the same precision as the 64-bit double type in .NET

• In C#, ‘float’ is of 32-bit, hence it’s more equivalent in SQL to the float(24)/real data-type in MSSQL than the float(53)/float.

• In your case, to represent the latitude and longitude within one-meter precision you need 5 places after the decimal point and for the degrees you need up to 3 digits before the decimal point.

• In MSSQL, you can use float(24) or decimal(8,5) which will be best according to your needs. But, if you are working in C# then the float is good enough.

• For users, it’ll be more convenient to round up to 5 decimal places rather than a bunch of insignificant digits.