Question

Is there any similar thing like SQL Server’s UDF (where a function can be exported in a DLL and imported as a function in SQL Server) in Postgres?

For example the function I want to import has the following signature:

public static extern double* svd(double[] a, int d);

the Dll import looks like this:

[DllImport("D:\\my.dll", EntryPoint = "mydll")]

Answer 1

You can use the Create Function in Postgres:

CREATE FUNCTION svd(double*, int) RETURNS double*
AS 'c:/path/mydll.dll'
LANGUAGE 'C';

More info: http://www.postgresql.org/docs/current/static/xfunc-c.html

You’ll likely need to use composite types since it appears you’re manipulating matricies with variable numbers of rows and columns.