Where there is a will, there is a way... :-)
On 2011-02-16, at 9:34 PM, Michael Schrag wrote: > Re: removing/renaming --- you just can't remove until one version later. > You'd have to trigger manage updates in the meantime. The pain you go through > is just a factor of how much you can't go down :) > > Sent from my iPad > > On Feb 16, 2011, at 11:04 PM, Chuck Hill <ch...@global-village.net> wrote: > >> On Feb 16, 2011, at 7:19 PM, Michael Schrag wrote: >>>> >>>> Be aware that it might cause problems if you deploy a new version that do >>>> database schema changes. For example, if you change the constraint on a >>>> column so that it cannot accept NULL anymore and the older version of your >>>> app don't have that change in its model, current sessions in the older >>>> version will get an JDBC exception when they try to put NULL in the column >>>> where the constraint was changed. >>>> >>>> Many other database changes will also cause problems. If you need to >>>> update the schema, you pretty much have to schedule a service outage. >>> You just have to be a lot more careful and have stricter rules about what >>> kind of changes you allow. For instance, you can't add new not null >>> constraints unless you have default values (at least initially). >>>> >> >> OK, that was a rather large brush for me to tar it with. Removing or >> renaming columns is a problem that I don't think you can get around. >> Adding nullable columns is OK. >> >> >> Chuck >> >> -- >> Chuck Hill Senior Consultant / VP Development >> >> Practical WebObjects - for developers who want to increase their overall >> knowledge of WebObjects or who are trying to solve specific problems. >> http://www.global-village.net/products/practical_webobjects >> >> >> >> >> >> >> -- Chuck Hill Senior Consultant / VP Development Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems. http://www.global-village.net/products/practical_webobjects
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