Rails model user ID PG ERROR: NotNullViolation

Question

I'm using rails 4, postgres 9.3 and devise, and at the moment of sign up an user, I'm getting the error of :

    PG::NotNullViolation: ERROR: the null value for column « usuario_id » violates the constraint not null. 

The primary key or ID of the table or model usuario is usuario_id and it's an integer.

I understand that it violates de constraint, but how can I autoincrement the ID without entering it through the sign up form?

I didn't do the migration 'cause it's unnecessary because I already have the tables in postgres. The only columns that I add are the devise ones. Anyway this is the table from postgresql.

                           Tabla «public.usuario»
    Column         |            Type            |                  Modifiers                   
------------------------+-----------------------------+---------------------------------
usuario_id             | integer                     | not null
comuna_id              | integer                     | not null
usuario_nombre         | character(256)              | 
usuario_apellidopat    | character(256)              | 
usuario_apellidomat    | character(256)              | 
usuario_rut            | character varying(1024)     | 
email                  | character varying(1024)     | 
usuario_nombre_usuario | character(256)              | 
password               | character varying(128)      | 
usuario_vip            | boolean                     | 
usuario_calle          | character varying(128)      | 
usuario_numero_calle   | smallint                    | 
usuario_villa          | character varying(128)      | 
usuario_numero_depto   | smallint                    | 
usuario_bloque         | smallint                    | 
encrypted_password     | character varying(255)      | not null valor por omisión      
reset_password_token   | character varying(255)      | 
reset_password_sent_at | timestamp without time zone | 
remember_created_at    | timestamp without time zone | 
sign_in_count          | integer                     | not null valor por omisión 0
current_sign_in_at     | timestamp without time zone | 
last_sign_in_at        | timestamp without time zone | 
current_sign_in_ip     | character varying(255)      | 
last_sign_in_ip        | character varying(255)      | 
confirmation_token     | character varying(255)      | 
confirmed_at           | timestamp without time zone | 
confirmation_sent_at   | timestamp without time zone | 
unconfirmed_email      | character varying(255)      | 
 Índexes:
"pk_usuario" PRIMARY KEY, btree (usuario_id)
"index_usuario_on_reset_password_token" UNIQUE, btree (reset_password_token)
"usuario_pk" UNIQUE, btree (usuario_id)
"relationship_34_fk" btree (comuna_id)
Foreign key constraints:
"fk_usuario_relations_comuna" FOREIGN KEY (comuna_id) REFERENCES comuna(comuna_id) ON UPDATE RESTRICT ON DELETE RESTRICT
Referenced by:
TABLE "compra_remate" CONSTRAINT "fk_compra_r_relations_usuario" FOREIGN KEY (usu_usuario_id) REFERENCES usuario(usuario_id) ON UPDATE RESTRICT ON DELETE RESTRICT
TABLE "compra_remate" CONSTRAINT "fk_compra_r_relations_usuario2" FOREIGN KEY (usuario_id) REFERENCES usuario(usuario_id) ON UPDATE RESTRICT ON DELETE RESTRICT
TABLE "compra_venta_especial" CONSTRAINT "fk_compra_v_relations_usuario" FOREIGN KEY (usu_usuario_id) REFERENCES usuario(usuario_id) ON UPDATE RESTRICT ON DELETE RESTRICT
TABLE "compra_venta_normal" CONSTRAINT "fk_compra_v_relations_usuario" FOREIGN KEY (usu_usuario_id) REFERENCES usuario(usuario_id) ON UPDATE RESTRICT ON DELETE RESTRICT
TABLE "compra_venta_especial" CONSTRAINT "fk_compra_v_relations_usuario2" FOREIGN KEY (usuario_id) REFERENCES usuario(usuario_id) ON UPDATE RESTRICT ON DELETE RESTRICT
TABLE "compra_venta_normal" CONSTRAINT "fk_compra_v_relations_usuario2" FOREIGN KEY (usuario_id) REFERENCES usuario(usuario_id) ON UPDATE RESTRICT ON DELETE RESTRICT
TABLE "notificacion" CONSTRAINT "fk_notifica_relations_usuario" FOREIGN KEY (usuario_id) REFERENCES usuario(usuario_id) ON UPDATE RESTRICT ON DELETE RESTRICT
TABLE "prod_of_nec" CONSTRAINT "fk_prod_of__relations_usuario" FOREIGN KEY (usuario_id) REFERENCES u:

Answer 1

First, in your User model migration, did change the primary key for the user table to be usuario_id ? See the following Stackoverflow question:

• How to change primary key in rails migration file?

Second, did you make sure that you overrode the naming convention for the primary key in your ActiveRecord models?

Something like this:

class User < ActiveRecord::Base
  self.primary_key = "usuario_id"
end

See the following section in the Rails Guide for more details.