> > On Wed, Sep 1, 2010 at 8:59 AM, Dobrysmak <[email protected]>wrote: > Hi. > Okay, thanks ;-) > > This solution seems pretty good, but can i associate two records from > MESSAGES_USERS_RECIEVING and MESSAGES_USERS_SENDING to one (the same) > message record in messages table? If yes, then how? >
Yes, you can! ;) Looking on design, you can have the message "Hello" sent from "John" (a user) to "Mary" (other user), then you will have the following rows on database: *Table messages:* ID TEXT 1 Hello *Table users:* ID NAME 1 John 2 Mary *Table messages_users_receiving:* ID MESSAGE_ID USER_ID 1 1 2 (Mary) *Table messages_users_sending *ID MESSAGE_ID USER_ID 1 1 (the same) 1 (John) But here you can check your model: a message can be sent to one or more users, but can a message be sent from more than one user? If a message is sent only by a user, you should have a many to one relationship between message and user (the sender), and a many to many relationshop between the same tables (the receivers, that can be one or more users). Best regards, Francisco Souza Software developer at Giran and also full time Open source evangelist at full time English: http://www.franciscosouza.net Portuguese: http://www.franciscosouza.com.br Twitter: @franciscosouza +55 27 3026 0264 On Wed, Sep 1, 2010 at 8:59 AM, Dobrysmak <[email protected]>wrote: > Hi. > Okay, thanks ;-) > > This solution seems pretty good, but can i associate two records from > MESSAGES_USERS_RECIEVING and MESSAGES_USERS_SENDING to one (the same) > message record in messages table? If yes, then how? > > > > On 1 Wrz, 13:04, Francisco Souza <[email protected]> wrote: > > > On Wed, Sep 1, 2010 at 5:14 AM, Dobrysmak <[email protected] > >wrote: > > > [...] > > > > > "ConcurrentModificationError: Updated rowcount 0 does not match number > > > of objects updated 1" > > > > > Mabey there's a better way to do this? > > > Anyone have a clue? > > > > Hi :) > > > > you should have to many-to-many relationships and two association tables: > > messages_users_receiving and messages_users_sending. > > > > So you configure two many to many relationships with different secondary > > tables. > > > > Cheers, > > Francisco Souza > > Software developer at Giran and also full time > > Open source evangelist at full time > > > > English:http://www.franciscosouza.net > > Portuguese:http://www.franciscosouza.com.br > > Twitter: @franciscosouza > > +55 27 3026 0264 > > > > On Wed, Sep 1, 2010 at 5:14 AM, Dobrysmak <[email protected] > >wrote: > > > > > > > > > Hi. > > > I'm building a db with many-to-many relations, ex. > > > * Table Users > > > * Table Messages > > > * Table Messages_Users > > > > > when the users sends a message to other users i'm inserting that > > > message to the db like so, > > > > > *Messages <- insert 1 row with the message, values ( title, text , > > > date, etc... ) > > > > > *Messages_Users <- insert 2 rows ( one with connetion to the sending > > > user and message,second with connection to the recieving user and > > > message), values ( user_id, message_id, id_from, id_to, etc...) > > > > > at the process of inserting the second row to the Messages_Users table > > > i'm getting an error, > > > > > "ConcurrentModificationError: Updated rowcount 0 does not match number > > > of objects updated 1" > > > > > Mabey there's a better way to do this? > > > Anyone have a clue? > > > > > -- > > > You received this message because you are subscribed to the Google > Groups > > > "sqlalchemy" group. > > > To post to this group, send email to [email protected]. > > > To unsubscribe from this group, send email to > > > [email protected]<sqlalchemy%[email protected]> > <sqlalchemy%2bunsubscr...@googlegrou ps.com> > > > . > > > For more options, visit this group at > > >http://groups.google.com/group/sqlalchemy?hl=en. > > -- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<sqlalchemy%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/sqlalchemy?hl=en. > > -- You received this message because you are subscribed to the Google Groups "sqlalchemy" 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/sqlalchemy?hl=en.
