On Sun, Jan 8, 2012 at 21:31, Mike Christensen <mike@xxxxxxxxxxxxx> wrote: > On Sun, Jan 8, 2012 at 10:12 AM, Francisco Figueiredo Jr. > <francisco@xxxxxxxxxx> wrote: >> On Sun, Jan 8, 2012 at 06:54, Mike Christensen <mike@xxxxxxxxxxxxx> wrote: >>>>>>>> According to the manuals, Postgres has smallint (2 byte), integer (4 >>>>>>>> bytes) and bigint (8 bytes).. I use a lot of structures with "bytes" >>>>>>>> in my code and it's kinda annoying to cast DB output from Int16 to >>>>>>>> Byte every time, especially since there's no explicit cast in .NET and >>>>>>>> you have to use System.Convert(). >>>>>>>> >>>>>>>> Is there a work-around, or do people just cast or use Int16 in their >>>>>>>> data structures? Just wondering.. I know on modern computers it >>>>>>>> probably doesn't make any difference anyway.. >>>>>>> >>>>>>> >>>>>>> Is this just about programmer convenience or is it about space efficiency >>>>>>> in >>>>>>> the database? BYTEA might help you. Or try declaring a DOMAIN over >>>>>>> SMALLINT that limits allowed values to the range of a byte. -- Darren >>>>>>> Duncan >>>>>> >>>>>> >>>>>> This is purely programmer convenience. >>>>>> >>>>>> Basically, I want Npgsql to marshal the value as a .NET Byte type, if >>>>>> I can find a way to do that I'm happy. Perhaps it's more of a Npgsql >>>>>> question, though I'm curious as to why Postgres doesn't have an >>>>>> intrinsic tinyint or byte type. >>>>> >>>>> >>>>> Maybe Postgres doesn't need a Byte type predefined because it gives you the >>>>> means to define the type yourself, such as using DOMAIN. >>>>> >>>>> Generally speaking, I believe it is more important for a type system to >>>>> provide the means for arbitrary user-defined types which can be used in all >>>>> the places as built-in-defined types, than to have large numbers of >>>>> built-in-defined types. >>>> >>>> Precisely. postgresql's extensable nature allows you to build your >>>> own types as well. If it's popular enough it'll make it into contrib, >>>> then maybe core. My guess is that there's some non-trivial cost to >>>> maintaining each core type, and since a byte type isn't required by >>>> the SQL spec, it would take some effort to get a standard one included >>>> in the core. >>> >>> That makes sense. >>> >>> I guess my question is more of a NpgSql question then. Is there a way >>> to create a custom PG type, and have npgsql serialize that type in a >>> dataset to a .NET Byte type? >>> >>> I'd probably be better off posting on the npgsql mailing list, but >>> perhaps someone here knows as well.. >>> >> >> >> Hi! >> >> Npgsql already has support to map .Net byte data type to int2 and vice-versa. >> >> You can see all the supported type mappings in this file: >> http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/npgsql/Npgsql2/src/NpgsqlTypes/NpgsqlTypesHelper.cs?rev=1.41&content-type=text/x-cvsweb-markup >> >> Check method PrepareDefaultTypesMap(). >> >> I hope it helps. > > Thanks! I'll have to mess around with this a bit more.. From what > I've seen so far, functions that have int2 out parameters will return > Int16 through the DataReader.. Maybe I'm doing something wrong.. > > Mike I think you aren't doing anything wrong. int2 postgresql datatypes are supposed to be mapped to .net int16 types. Do you have a simple example? What type were you expecting in the datareader? Maybe there is a missing mapping in Npgsql. Thanks in advance. -- Regards, Francisco Figueiredo Jr. Npgsql Lead Developer http://www.npgsql.org http://gplus.to/franciscojunior http://fxjr.blogspot.com http://twitter.com/franciscojunior -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
