Cayenne generates the appropriat AUTO_PK_SUPPORT table regardless of the pk generation strategy, but if your pk generation strategy is "Database Generated" (AND if your db + driver support auto-pk generation), it won't actually use it; it will allow the database to generate the id and use the generated id.
Robert On Tue, Apr 20, 2010 at 9:15 AM, Joe Baldwin <[email protected]>wrote: > Michael, > > I need a simple verification (because the webhost tech person is very > confused). > > To explain further: I am using Cayenne Modeler to design the entities, and > to create the database tables in MySQL. (i.e. Tools - Generate Database > Schema). My understanding, and my tests have proved, if you set [PK > Generation Strategy] to "Database-Generated", and [Auto Incremented] to "oid > (INTEGER)" then Cayenne Modeler will "request/instruct/ask " MySQL to create > a table, then set the oid as the primary key, and set auto_increment to > "true" for that field. > > The following code was generated by the Cayenne Modeler (I deleted > everything not having to do with the table or key) > > CREATE TABLE pickers.product (PRIMARY KEY (oid)) ENGINE=InnoDB; > CREATE TABLE AUTO_PK_SUPPORT ( TABLE_NAME CHAR(100) NOT NULL, > NEXT_ID BIGINT NOT NULL, UNIQUE (TABLE_NAME)); > DELETE FROM AUTO_PK_SUPPORT WHERE TABLE_NAME IN ('product'); > INSERT INTO AUTO_PK_SUPPORT (TABLE_NAME, NEXT_ID) VALUES ('product', > 200); > > > The question now is: Has Cayenne Modeler generated SQL that creates a table > named "product", with a primary key "oid", whose value is automatically > created by MySQL's InnoDB engine, using auto_increment, at the time of the > INSERT? Another way of asking this is: In this scenario, does Cayenne > generate the key, or does MySQL generate the key? > > I would like to forward a brief response to the webhost. > > Thanks, > Joe > > > > > On Apr 20, 2010, at 9:25 AM, Michael Gentry wrote: > > > Hi Joe, > > > > Your wording on #2 and #3 was a little curious to me. I don't know if > > you used Cayenne Modeler to generate your schema or if you are using > > an existing schema. Cayenne (at runtime) doesn't really instruct the > > database (MySQL) to auto-generate keys. Cayenne will nont provide a > > value for "oid" when inserting the record and that essentially > > instructs MySQL to auto-generate a key. You set this up when you > > create your product table, for example. The database needs to know > > that it is responsible for auto-generating the keys -- Cayenne won't > > tell it at runtime (other than leaving the key out on insert). > > > > Maybe I'm a bit off on what you were asking, but it seems like you are > > expecting Cayenne to tell MySQL to generate the keys when it actually > > works the other way around: MySQL is supposed to know to generate the > > key and Cayenne then asks it for the key it generated. > > > > mrg > > > > PS. BTW, your settings are correct to use the auto-generated key > > feature in MySQL, just be sure the table was created to auto-generate > > on your "oid" column. > > > > > > On Mon, Apr 19, 2010 at 8:03 PM, Joe Baldwin <[email protected]> > wrote: > >> I apologize for this, but I am being forced to verify a configuration > that is pretty obvious. > >> > >> Please refer to the attached CM configuration panel for an Entity. > >> > >> 1. The Primary Key "PK Generation Strategy" is set to > "Database-Generated". Please verify that this means that the PK Generation > Strategy is Database Generated. > >> 2. The Primary Key "Auto Increment" is set to "oid (INTEGER)". Please > verify that the field being auto-incremented is "oid". > >> 3. Please verify that (with the DBMS set to MySQL) that the two previous > parameters instruct MySQL to use its auto_increment feature to create a new > "oid" value for inserted records. > >> > >> Thanks > >> Joe > >> > >> > >> > >
