ERROR: null value in column violates not-null constraint

Question

CREATE TABLE medico
    (num_cedula serial NOT NULL UNIQUE,
     nome varchar(20) NOT NULL,
     especialidade varchar(20) NOT NULL,
     PRIMARY KEY(num_cedula));

CREATE TABLE consulta
    (num_cedula serial NOT NULL,
     num_doente serial NOT NULL,
     data_consulta date NOT NULL,
     nome varchar(20) NOT NULL,
     CHECK(EXTRACT(DOW FROM data_consulta) NOT IN (6,0)),
     UNIQUE(num_doente,data_consulta,nome),
     FOREIGN KEY(nome) REFERENCES instituicao(nome) ON UPDATE CASCADE,
     FOREIGN KEY(num_cedula) REFERENCES medico(num_cedula) ON UPDATE CASCADE,
     PRIMARY KEY(num_cedula,num_doente,data_consulta));

CREATE TABLE analise
    (num_analise serial NOT NULL UNIQUE,
     especialidade varchar(20) NOT NULL,
     num_cedula serial ,
     num_doente serial ,
     data_analise date ,
     data_registo date NOT NULL,
     nome varchar(20) NOT NULL,
     quant integer NOT NULL,
     inst varchar(20) NOT NULL,
     CONSTRAINT fk_analise FOREIGN KEY(num_cedula,num_doente,data_analise) REFERENCES consulta(num_cedula,num_doente,data_consulta) ON UPDATE CASCADE,
     FOREIGN KEY(inst) REFERENCES instituicao(nome) ON UPDATE CASCADE,
     PRIMARY KEY(num_analise));

这是我的代码，但是当我尝试插入另一个带有 num_cedula、num_doente、data_analise 作为 NULL 的“分析”时，它给了我这个错误（“错误：空值在“num_cedula”列中违反了非空约束详细信息：失败行包含 (32, Ortopedia, null, null, null, 2019-12-02, glicemia, 176, Instituicao1)。 SQL state: 23502") 我真的不知道为什么。另外，这是我使用的插入代码：

INSERT INTO analise VALUES(32,'Ortopedia',NULL,NULL,NULL,'2019-12-02','glicemia',176,'Instituicao1');

Answer 1

serial 数据类型不允许 null 值。 documentation 解释了在声明 serial 时幕后发生的事情（重点是我的）：

Thus, we have created an integer column and arranged for its default values to be assigned from a sequence generator. A NOT NULL constraint is applied to ensure that a null value cannot be inserted.

我不认为你真的想要 serial 这里。该数据类型的用例是创建一个自动递增的列。您可以改用 int，这样可以避免您遇到的问题。

ERROR: null value in column violates not-null constraint

ERROR: null value in column violates not-null constraint

sql

postgresql

foreign-keys

create-table