Re: violates not-null constraint question.

From: Joshua Pyle (joshua.t.pyl..mail.com)
Date: Sun Mar 12 2006 - 03:15:01 EST

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    Mike makes a point that I had trouble seeing when I first started
    using ORM's. In order to use the default values the ORM would havre
    the object and then read it evry time and insert or update was
    performed. This would cause slowdown and inefficiency.

    In the end default database values and an ORM just don't mix.

    --
    Joshua T. Pyle
    Go has always existed.
    

    On 3/11/06, Mike Kienenberger <mkienen..mail.com> wrote: > If you don't care about keeping the java object graph and the database > record in sync, then manually create the insert statement using an SQL > Template or with a direct JDBC call. > > There's no point using "regular Cayenne objects" in this case. > > It's not that I think that using "DB Default value" is bad. I think > default db values are a wonderful idea when used appropriately. > However, the use of a default DB value is incompatible with using an > ORM product like Cayenne since the java object state needs to match > the database record state for ORM to work. > > > > On 3/11/06, WONDER <mmmmmmmmm5..eb.de> wrote: > > Well It looks like the discussion going in the theme using DB default value > > or not. > > > > Your opinion is "using DB default value is bad". > > My opinion is "very good and important". > > > > You dont like it, so its ok for you, but I think its not good idea to > > prevent another developers using DB default value. > > > > btw, indeed solution 1 is not for me, and 2 is not practical. > > I want to use DB default value to do NOT set the value in java :) > > > > Accoring to I insert object in the DB, I know that the object and DB are > > going out of sync. As long as i know that, its ok. > > The problem i see, I know what i want and need "using DB default value", but > > i cant. > > > > Sako. > > > > > > ----- Original Message ----- > > From: "Mike Kienenberger" <mkienen..mail.com> > > To: <cayenne-use..bjectstyle.org> > > Sent: Sunday, March 12, 2006 1:12 AM > > Subject: Re: violates not-null constraint question. > > > > > > No, this is how it should work. There's a difference between "allows > > null" and providing a default non-null value. > > > > I think there are two ways you can handle this. > > > > 1) Don't put your is_active column in your model. This is probably > > not realistic in your case. > > > > 2) Have your generated Entity java class set the default rather than > > relying on the database to set the default. When you create the > > object, set a default value for that column. > > > > There are probably a number of reasons why having the database set the > > default is a bad idea, but the primary one is that there's no way for > > your java representation of the object to know what the database is > > doing, and your java object and your database record will be out of > > sync. > > > > > > On 3/11/06, WONDER <mmmmmmmmm5..eb.de> wrote: > > > It does not looks like you expliand. It is exactly as you explaind. > > > No i didnt recreate the table and i wont do that. > > > > > > I want to have it "disallow null" in DB and "allow null" in the model. > > > The default value in the DB should insert the default value. > > > > > > The problem is Cayenne sends "NULL" to DB. > > > > > > I dont think its good style to use NULL at all in Cayenne. According to > > > sending NULL to db mean > > > I have no way to use the defaul value feature of the DB. This is nonsence, > > > isnt it? > > > > > > Sako. > > > > > > ----- Original Message ----- > > > From: "Mike Kienenberger" <mkienen..mail.com> > > > To: <cayenne-use..bjectstyle.org> > > > Sent: Saturday, March 11, 2006 10:33 PM > > > Subject: Re: violates not-null constraint question. > > > > > > > > > It looks like you have set the is_active field as "allows null" in the > > > modeler, but you have set the database constraints to be "disallows > > > null". > > > > > > Have you tried recreating the table after making the mandatory change? > > > Or altering the table column to be nullable? > > > > > > -Mike > > > > > > > > > On 3/11/06, WONDER <mmmmmmmmm5..eb.de> wrote: > > > > Hello, > > > > > > > > CREATE TABLE account > > > > ( > > > > id int4 NOT NULL, > > > > username varchar(50) NOT NULL, > > > > "password" varchar(100) NOT NULL, > > > > is_checked bool DEFAULT false, > > > > > > > > ... > > > > > > > > In the Model i have unchecked DbEntity.Mandatory for "is_active" to > > > false. > > > > > > > > I get this error > > > > > > > > ERROR: null value in column "is_active" violates not-null constraint > > > > > > > > Is there any way to get arround this? > > > > > > > > I really dont know what sence does it make to send a NULL value to the > > DB > > > as > > > > > > > > ---------------------------------------------------------------- > > > > > > > > INSERT INTO public.account (id, inactive_username, is_active, > > is_checked, > > > > password, username) VALUES (?, ?, ?, ?, ?, ?) > > > > > > > > [batch bind: 47, NULL, NULL, 'false', '*****', 'XXXXX'] > > > > > > > > ---------------------------------------------------------------- > > > > > > > > It makes the default value technique useless, i hope there is way to > > > disable > > > > this. > > > > > > > > > > > > > > > > Sako. > > > > > > > > > > > > > > > > > > > > > > > > > > >



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