Assuming you mean that the database type is decimal(6, 2), then this means that your column is set up to store 6 places (scale), with 2 to the right of the decimal (precision). You should treat this as a decimal CLR type. A sample would be 1234.56 .
The syntax for the double data type is DOUBLE PRECISION(m,d) where ‘m’ is the total number of digits and ‘d’ is the number of digits following the decimal point. For example, DOUBLE(7,5) means that it will store a value with seven digits and five decimals.