[c#] What represents a double in sql server?

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.

You should map it to FLOAT(53)- that's what LINQ to SQL does.

It sounds like you can pick and choose. If you pick float, you may lose 11 digits of precision. If that's acceptable, go for it -- apparently the Linq designers thought this to be a good tradeoff.

However, if your application needs those extra digits, use decimal. Decimal (implemented correctly) is way more accurate than a float anyway -- no messy translation from base 10 to base 2 and back.

float is the closest equivalent.

SqlDbType Enumeration

For Lat/Long as OP mentioned.

A metre is 1/40,000,000 of the latitude, 1 second is around 30 metres. Float/double give you 15 significant figures. With some quick and dodgy mental arithmetic... the rounding/approximation errors would be the about the length of this fill stop -> "."

Also, here is a good answer for SQL-CLR Type Mapping with a useful chart.

From that post (by David):

A Float represents double in SQL server. You can find a proof from the coding in C# in visual studio. Here I have declared Overtime as a Float in SQL server and in C#. Thus I am able to convert

int diff=4;
attendance.OverTime = Convert.ToDouble(diff);

Here OverTime is declared float type

For SQL Sever:

Decimal Type is 128 bit signed number Float is a 64 bit signed number.

The real answer is Float, I was incorrect about decimal.

The reason is if you use a decimal you will never fill 64 bit of the decimal type.

Although decimal won't give you an error if you try to use a int type.

Here is a nice reference chart of the types.

float in SQL Server actually has [edit:almost] the precision of a "double" (in a C# sense).

float is a synonym for float(53). 53 is the bits of the mantissa.

.NET double uses 54 bits for the mantissa.