On Saturday 30 August 2008 5:23:25 am Albretch Mueller wrote: > On Thu, Aug 28, 2008 at 7:50 PM, Adrian Klaver <aklaver@xxxxxxxxxxx> wrote: > > Define easily. > > ~ > OK, let me try to outline the approach I would go for: > ~ > I think "COPY FROM CSV" should have three options, namely: > ~ > 1) the way we have used it in which you create the table first > ~ > 2) another way in which defaults are declared, generally as: > ~ > 2.1) aggressive: data type, value and formatting analysis is done; if > only 1 or 0 are found declare then a BOOLEAN, if repeated data is > found (say state codes) and the stratification nodes cover the rest of > the data, stratify the data out to other extra table (they have a name > I can't recall now), index it ..., if data is kind of numeric with > front slashes and/or hyphen could they possibly be dates? if they are > definitelly dates convert them to bigint (and do the formatting in the > presentation code (also this a win-win situation with i18n code)) ... > ~ > 2.2) conservative: data type and value, but no formatting analysis is > done and the greater encompassing data type is selected, say for 1 or > 0 data use bytes [0, 255], for bytes use int, if something could be > encoded as char(2), use varchar instead, . . . > ~ > 2.3) dumn: just use the coarsest data type possible; bigint for > anything that looks like a number and varchar for the rest > ~ > the "dumn" option should suggest to the DBA the option they are > using, quantified consequences for their desicions (larger DBs for no > reason, approx. reduction in speed, . .) and how not to be "dumn" > ~ > 3) or you could define "import templates" declaring which specific > data types to use for data in a certain way, which could be declared > per column using regexps > ~ > > > I could go on, but the point is that table data types require some > > thought on the part of the DBA. > > ~ > Well, it still requires their minds and input, but they will have > jobs even if they get some help, don't you think so ;-) > ~ > lbrtchx This is a combination of more work then necessary and putting the cart after the horse. All I can see happening is delaying the point of decision to a later time and or dumping the decision process on someone else. There is already a "dumb" solution that has been brought many times on this list. It involve creating a holding table that has text only fields and copying the data into and then moving the data from there to a final table. As far as import templates I suggest looking at: http://pgloader.projects.postgresql.org/ It also addresses some of your other suggestions. It does not automatically create a table though. -- Adrian Klaver aklaver@xxxxxxxxxxx
