Hi, regarding the usage of "XORable" on page 145: ---begin include--- PAGE 145 SQLXorable is something that can be XORed, for example in orderby and groupby expressions. The Field class is derived from SQLXorable. Here is an example.
1. myorder=db.mytable.myfield.upper() | db.mytable.id 2. db().select(db.table.ALL,orderby=myorder) ---end include--- An XOR is an "eXclusive" OR which tests if the inputs are the same or different, resulting in a True if and only if one but not both inputs are True, and False otherwise. (reference: http://en.wikipedia.org/wiki/Truth_table) A B XOR ========= F F F F T T T F T T T F >From the code example that follows on pg145 it seems to me that you are referring to the OR function (by using the bitwise OR operator '|') which can be used to set flags in a bitfield (or is this operator overloaded?) I am unfamiliar with the use of "XOR" in this context. Is this an error? As I read this section while thinking of the XOR function, it makes no sense to me. I take it that the meaning is that one, two or more fields can be flagged as included. Does this bitwise or'ing mean that the first field is the dominant and the second field is the minor field in the sorting order? Is it the default ordering of value content (string order, numeric order) of the fields that are included in the or'ing? So if I wanted to sort first by "id" in the example above, I would list it first in the or'ing ? --- Rb On Jul 11, 7:57 am, Massimo Di Pierro <[email protected]> wrote: > Chapters 7 and 8 have been revised including corrections from Mr > Admin, Fran and Jonathan. > > web2py_manual_678.pdf > 1982KViewDownload --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "web2py Web Framework" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/web2py?hl=en -~----------~----~----~----~------~----~------~--~---
