Gareth, this is awesome! Thanks for taking the time to answer in detail, I get it now and my horizon just expanded "by a bit"..... *drumroll!* ;)
Really, thanks, this is cool. Great link as well, I'll be reading up on this. Have a great day! Daniel On Apr 29, 10:48 pm, Gareth McCumskey <gmccums...@gmail.com> wrote: > Oh yes and per your original question .. the Criteria:BINARY_AND is a way to > tell your database to do a bitwise comparison. In SQL that would be & (not > &&) just like in PHP. > > On Thu, Apr 30, 2009 at 7:45 AM, Gareth McCumskey <gmccums...@gmail.com>wrote: > > > > > It uses an integer type, or tiny int if you will not be using many types. > > The bitwise operations don't need any specific type. If you want more info > > there is a nice little tutorial at > >http://www.litfuel.net/tutorials/bitwise.htm. That should explain better. > > Perhaps another small example here would help. This is directly from our > > code, from a batch script that does not use symfony to transfer > > classifications from the old "column per classification" schema of the old > > system mentioned in my blog post to the new schema using binary: > > > $classification_value = 0; > > > $classification_value = $get_batch_result->fields['isspam'] == 1 ? > > $classification_value + 1 : $classification_value; > > > $classification_value = $get_batch_result->fields['ishighspam'] == 1 ? > > $classification_value + 2 : $classification_value; > > > $classification_value = $get_batch_result->fields['issaspam'] == 1 ? > > $classification_value + 4 : $classification_value; > > > $classification_value = $get_batch_result->fields['isrblspam'] == 1 ? > > $classification_value + 8 : $classification_value; > > > $classification_value = $get_batch_result->fields['isfp'] == 1 ? > > $classification_value + 16 : $classification_value; > > > $classification_value = $get_batch_result->fields['spamwhitelisted'] == 1 ? > > $classification_value + 32 : $classification_value; > > > $classification_value = $get_batch_result->fields['spamblacklisted'] == 1 ? > > $classification_value + 64 : $classification_value; > > > $classification_value = $get_batch_result->fields['virusinfected'] == 1 ? > > $classification_value + 128 : $classification_value; > > > $classification_value = $get_batch_result->fields['nameinfected'] == 1 ? > > $classification_value + 256 : $classification_value; > > > $classification_value = $get_batch_result->fields['otherinfected'] == 1 ? > > $classification_value + 512 : $classification_value; > > > $classification_value = $get_batch_result->fields['quarantined'] == 1 ? > > $classification_value + 1024 : $classification_value; > > > The reason it works is because in PHP you can take a value from the > > classification and do a bitwise if: > > > if ($classification_value & 512) > > > So if the classification value had 512 (otherinfected) added onto it the > > result would be true. Another example is if I had a classification value of > > 768: > > > if ($classification_value & 512) > > > would still return true as well as: > > > if ($classification_value & 256) > > > and nothing else would because 512 + 256 = 768. > > > Hope that helps a bit more > > > On Thu, Apr 30, 2009 at 1:47 AM, Richtermeister <nex...@gmail.com> wrote: > > >> Hi Gareth, > > >> thanks for the explanation. The part about the 1, 2, 4, 8 step I get.. > >> but to me those would still be integers.. albeit not continuous. > >> I guess I am just not familiar with the bit datatype and how it is > >> used. > > >> If you don't mind me asking, what database storage type does this use? > > >> Thanks, > >> Daniel > > >> On Apr 29, 2:38 pm, Gareth McCumskey <gmccums...@gmail.com> wrote: > >> > If you used just integers then you wouldn't be able to work backwards > >> from > >> > the totalled number. For example: > > >> > - is_low_socring = 1 > >> > - is_high_scoring = 2 > >> > - is_virus = 3 > >> > - is_badcontent = 4 > > >> > If I had something that was just bad content it would be a 4. But If I > >> had > >> > something that was low_scoring and a virus it would also be 4... hmmm. > >> But > >> > if I use binary... > > >> > - is_low_socring = 1 > >> > - is_high_scoring = 2 > >> > - is_virus = 4 > >> > - is_badcontent = 8 > > >> > ONLY bad_content can be an 8, only low_scoring AND virus can be a 5 .. > >> etc > >> > etc. > > >> > Hope that helps > > >> > On Wed, Apr 29, 2009 at 6:01 PM, Richtermeister <nex...@gmail.com> > >> wrote: > > >> > > Hi Gareth, > > >> > > I just read your blog entry on that subject, and I have to admit that > >> > > it never occurred to me to use bits to store multiple flags in one > >> > > column. I like it! :) Thanks. > > >> > > My question, if I may, is why the classification column is not just an > >> > > integer? What is the Criteria::BINARY_AND for? > > >> > > Thanks for enlightening me :) > >> > > Have a great day. > >> > > Daniel > > >> > > On Apr 29, 1:09 am, Gareth McCumskey <gmccums...@gmail.com> wrote: > >> > > > Hi all, > > >> > > > I need the great minds that populate this liust to assist me with a > >> small > >> > > > dilema. We currently use an integer field that stores a range of > >> values > >> > > as a > >> > > > bitwise number depending on certain criteria of an item stored in > >> the db. > >> > > > What we want to do now is write a sql query like: > > >> > > > SELECT [columns] FROM [tablename] WHERE classification & 1 AND > >> > > > classification & ~2 > > >> > > > I am struggling to find the negation (~) operator as part of the > >> criteria > >> > > > syntax. So far I have: > > >> > > > $status_criterion = > >> $c->getNewCriterion(MailDetailsPeer::CLASSIFICATION, > >> > > 1, > >> > > > Criteria::BINARY_AND); > > >> $status_criterion->addAnd($c->getNewCriterion(MailDetailsPeer::CLASSIFICATION, > >> > > > 2 , Criteria::BINARY_AND)); > > >> > > > As you can see I have no negation on the second-line because I do > >> not > >> > > know > >> > > > how I should do that. There aren't any obvious options as part of > >> Propel. > > >> > > > ANy help would be appreciated guys :) > > >> > > > -- > >> > > > Gareth McCumskeyhttp://garethmccumskey.blogspot.com > >> > > > twitter: @garethmcc > > >> > -- > >> > Gareth McCumskeyhttp://garethmccumskey.blogspot.com > >> > twitter: @garethmcc > > > -- > > Gareth McCumskey > > >http://garethmccumskey.blogspot.com > > twitter: @garethmcc > > -- > Gareth McCumskeyhttp://garethmccumskey.blogspot.com > twitter: @garethmcc --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "symfony users" group. To post to this group, send email to symfony-users@googlegroups.com To unsubscribe from this group, send email to symfony-users+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/symfony-users?hl=en -~----------~----~----~----~------~----~------~--~---
