Stephan Szabo wrote:
When I say "same" I am talking about having a number 'stored' in double format in some client, inserting it in PostgreSQL float8 field and get it to the client as it was before:On Tue, 29 Oct 2002, Peter Eisentraut wrote:Pedro Miguel Frazao Fernandes Ferreira writes:Is there a way to set query output precision to maximum precision ? For the type of application I mentioned this is crucial. People want to get the 'same' numbers, from querys or dumps, as they inserted them.How do you define maximum precision and "same"? With simple test programs in C, using two digits more than DBL_DIG for printf specifier, it's easy for me to find numbers that "change" decimal string representation in the decimal representation -> double -> decimal representation conversion(*). The final double you get from the second conversion should be the same as the first, but is that what you need or do you need a stronger guarantee than that?
[Some client] (insert) [PostgreSQL] (query) [Some client]
(double number a)-------->(float8 number)------->(double number b)
"same" is so that a==b is true.
With current float8 output this is not allways true.
I believe this should allways be true for numbers which are originally stored in double format.
Thanks,
Pedro M. Ferreira
-- ---------------------------------------------------------------------- Pedro Miguel Frazao Fernandes Ferreira Universidade do Algarve Faculdade de Ciencias e Tecnologia Campus de Gambelas 8000-117 Faro Portugal Tel./Fax: (+351) 289 800950 / 289 819403 http://w3.ualg.pt/~pfrazao ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/users-lounge/docs/faq.html
