Grails

Grails documentation for discriminator has incorrect examples

Details

  • Type: Bug Bug
  • Status: Open Open
  • Priority: Minor Minor
  • Resolution: Unresolved
  • Affects Version/s: 1.1.1
  • Fix Version/s: None
  • Component/s: Documentation
  • Labels:
    None
  • Environment:
    n/a

Description

It appears that the documentation for discriminator has examples that are incorrect. Here is the URL to the documentation.

http://grails.org/doc/latest/ref/Database%20Mapping/discriminator.html

The example shows the following...

class Content {
...
}
class PodCast extends Content{
...
static mapping =

{ discriminator column:"content_type", value: "audio" }

}

However it has been my experience that placing the static mapping in the super class is required or the default column name will be used. I think this is how the example should read in order to specify your own column name for the discriminator.

class Content {
...
static mapping =

{ discriminator column:"content_type", value: "audio" }

}
class PodCast extends Content{
...
}

Thanks!

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Graeme Rocher added a comment -

Assigning all documentation related issues to 1.2 final since they don't represent a change to the codebase

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Graeme Rocher added a comment - Assigning all documentation related issues to 1.2 final since they don't represent a change to the codebase
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Joshua Burnett added a comment -

fixed here
http://github.com/basejump/grails-doc/commit/016aa7fcbc7c1b4170536533c094cafd416b247b

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Joshua Burnett added a comment - fixed here http://github.com/basejump/grails-doc/commit/016aa7fcbc7c1b4170536533c094cafd416b247b
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Dave Cramer added a comment -

I just tried the example in the docs fixed and with postgresql I get the following

create table entity (id int8 not null, version int8 not null, long2 int8 not null, long1 int8 not null, name varchar(255) not null, parent_id int8, discriminator varchar(-1) not null, primary key (id))

The class is:

class Entity {

Entity parent
String name
Long long1
Long long2

static mapping =

{ discriminator column:'discriminator',value:"foo" }

static constraints = {
}
}

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Dave Cramer added a comment - I just tried the example in the docs fixed and with postgresql I get the following create table entity (id int8 not null, version int8 not null, long2 int8 not null, long1 int8 not null, name varchar(255) not null, parent_id int8, discriminator varchar(-1) not null, primary key (id)) The class is: class Entity { Entity parent String name Long long1 Long long2 static mapping = { discriminator column:'discriminator',value:"foo" } static constraints = { } }
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kenwei added a comment -

To avoid the "varchar(-1)" problem in postgresql, I change the discriminator declaration as following:

class Entity {
String name

static mapping =

{ discriminator column: [name:'level', length:50] }

}

It finally works, but that causes another problem which is that discriminator value won't work in this class (but works fine in subclasses.)

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kenwei added a comment - To avoid the "varchar(-1)" problem in postgresql, I change the discriminator declaration as following: class Entity { String name static mapping = { discriminator column: [name:'level', length:50] } } It finally works, but that causes another problem which is that discriminator value won't work in this class (but works fine in subclasses.)

People

  • Assignee:
    Burt Beckwith
    Reporter:
    Daniel Mikusa
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    Updated:
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