Foreign key BIGSERIAL NULL Postgres - mysql

Question

I can not insert a record in the POSTGRES database, I want the foreign key to be null.
My table:
CREATE TABLE sad_avaliado (
id BIGSERIAL NOT NULL,
tenant_id INT8 NOT NULL,
funcionario_id BIGSERIAL NOT NULL,
epoca_id BIGSERIAL NOT NULL,
cca_id BIGSERIAL,
avaliador_id BIGSERIAL NOT NULL,
apagado boolean NOT NULL,
PRIMARY KEY (id)
);
alter table sad_avaliado add constraint sad_funcionario_fkey foreign key (funcionario_id) references sad_funcionario;
alter table sad_avaliado add constraint sad_epoca_fkey foreign key (epoca_id) references sad_epoca;
alter table sad_avaliado add constraint sad_cca_fkey foreign key (cca_id) references sad_cca;
alter table sad_avaliado add constraint sad_avaliador_fkey foreign key (avaliador_id) references sad_avaliador;
My SQL Insert:
INSERT INTO public.sad_avaliado(
id, tenant_id, funcionario_id, epoca_id, cca_id, avaliador_id, apagado)
VALUES (1, 1, 1, 1, null, 1, false);
My Error:
ERROR: null value in column "cca_id" violates not-null constraint

Answer 1

The foreign key references for BIGSERIAL should use BIGINT:
CREATE TABLE sad_avaliado (
id BIGSERIAL NOT NULL,
tenant_id INT8 NOT NULL,
funcionario_id BIGINT NOT NULL,
epoca_id BIGINT NOT NULL,
cca_id BIGINT,
avaliador_id BIGINT NOT NULL,
apagado boolean NOT NULL,
PRIMARY KEY (id)
);
I think this is the one exception to the notion that foreign key references should have the same type as the primary key. I mean, the underlying type is the same, but BIGSERIAL is used to specify that it is auto-incrementing (other databases use a separate keyword such as auto_increment or identity).

Answer 2

bigserial is meant for autoincremented id columns and it has default "not null" and creates one sequence.
And you should not specify your id in insert statements as it is inserted as default with nextval()
see this example
test=# create table test01 ( id bigserial );
CREATE TABLE
test=# \d test01*
Table "public.test01"
Column | Type | Collation | Nullable | Default
--------+--------+-----------+----------+------------------------------------
id | bigint | | not null | nextval('test01_id_seq'::regclass)
Sequence "public.test01_id_seq"
Type | Start | Minimum | Maximum | Increment | Cycles? | Cache
--------+-------+---------+---------------------+-----------+---------+-------
bigint | 1 | 1 | 9223372036854775807 | 1 | no | 1
Owned by: public.test01.id

Answer 3

Use bigint instead of bigserial.