Summary: We can't make some database migrates on MySQL because we can't DROP column with foreign key. Suggestions?
Em segunda-feira, 18 de agosto de 2014 09h46min49s UTC-3, Diogo Munaro escreveu: > > Hey guys, I'm trying to do CI (continuous integration) on web2py > application. > > I really need automatic database migration and web2py is really good with > it, but using MySQL I notice that we have some caveats > <http://www.web2py.com/books/default/chapter/29/06/the-database-abstraction-layer#MySQL> > : > > I can live without more than one alter table on migrations, but I can't > without this other caveat that is not specified by web2py but is on mysql > manual > <http://dev.mysql.com/doc/refman/5.6/en/create-table-foreign-keys.html>: > > Setting foreign_key_checks to 0 can also be useful for ignoring foreign >> key constraints during LOAD DATA and ALTER TABLE operations. *However, >> even if foreign_key_checks = 0, MySQL does not permit the creation of a >> foreign key constraint where a column references a nonmatching column type*. >> Also, if a table has foreign key constraints, ALTER TABLE cannot be used to >> alter the table to use another storage engine. To change the storage >> engine, you must drop any foreign key constraints first. >> > > So, I can't drop a column without dropping it's foreign key constraints > first, and I always get error 150 if I try. > > Now I'm migrating my database to Postgres, because web2py REALLY support > migrations on it. Just look this citation inside postgres manual > <http://www.postgresql.org/docs/9.1/static/sql-altertable.html>: > > *This form drops a column from a table. Indexes and table constraints >> involving the column will be automatically dropped as well.* You will >> need to say CASCADE if anything outside the table depends on the column, >> for example, foreign key references or views. If IF EXISTS is specified and >> the column does not exist, no error is thrown. In this case a notice is >> issued instead. >> > > What should we do to solve this issue with MySQL? A Stackoverflow > question > <http://stackoverflow.com/questions/338978/mysql-innodb-need-to-delete-column-and-accompanying-foreign-key-constraint-a> > said > that we should create a table replica, apply migrations on it and than > migrate data. > > I don't know any other migrations solutions that do it on python. I think > South have same problem because new Django 1.7 migration feature South-like > have a lot of caveats: > https://docs.djangoproject.com/en/dev/topics/migrations/ > > What do you think about make migrations as stackoverflow question suggest? > ( > http://stackoverflow.com/questions/338978/mysql-innodb-need-to-delete-column-and-accompanying-foreign-key-constraint-a > ) > > Is there another way to do that with MySQL? > > >> Regards > -- Resources: - http://web2py.com - http://web2py.com/book (Documentation) - http://github.com/web2py/web2py (Source code) - https://code.google.com/p/web2py/issues/list (Report Issues) --- You received this message because you are subscribed to the Google Groups "web2py-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to web2py+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
