Symfony Doctrine Insert: cannot insert into column "id"

Question

I'm modeling a vending machine where I got 3 Entities (Milk, Sugar, Coffee) and one table that lists all my coffee machines.

Now I want to insert a new value for the amount of milk left. The coffee machines are foreign keys in the resources tables.

However, I get this error, which does not seem to make sense, as I am just setting a foreign key field:

An exception occurred while executing a query: SQLSTATE[428C9]: <<Unknown error>>: 7 ERROR: cannot insert into column "id"
DETAIL: Column "id" is an identity column defined as GENERATED ALWAYS.
HINT: Use OVERRIDING SYSTEM VALUE to override.

Here are the tables (Postgres) (only coffee listed - milk and sugar have the same architecture):

create table coffee (
    id integer not null generated always as identity primary key,
    request_id bigint,
    logdate timestamp(0) without time zone not null,
    vmc_no integer,
    amount integer not null,
    constraint fk_request
        foreign key(request_id)
        references energyomat.request(id),
    constraint fk_vmc_company
        foreign key(vmc_no)
        references energyomat.vmc_company(vmc_no)
);

create table vmc_company (
    vmc_no integer not null unique primary key,
    register_date timestamp(0) without time zone not null
);

I've set the primitive fields and got the Entity of VmcCompany and set it as the foreign value (setVmcNo).

public function updateResources($vmcNo, $milkAmount, $sugarAmount, $coffeeAmount)
{
    $milk = new Milk();
    $sugar = new Sugar();
    $coffee = new Coffee();

    if($milkAmount != null) {
        $milk->setAmount($milkAmount);
        $milk->setLogdate(new \DateTime());
        $vmc = $this->doctrine->getRepository(VmcCompany::class)->find($vmcNo);
        $milk->setVmcNo($vmc);
        
        $manager = $this->doctrine->getManager();
        $manager->persist($milk);
    }

    if($sugarAmount != null) {
        $sugar->setAmount($sugarAmount);
        $sugar->setLogdate(new \DateTime());
        $vmc = $this->doctrine->getRepository(VmcCompany::class)->find($vmcNo);
        $sugar->setVmcNo($vmc);

        $manager = $this->doctrine->getManager();
        $manager->persist($sugar);
    }

    if($coffeeAmount != null) {
        $coffee->setAmount($coffeeAmount);
        $coffee->setLogdate(new \DateTime());
        $vmc = $this->doctrine->getRepository(VmcCompany::class)->find($vmcNo);
        $coffee->setVmcNo($vmc);

        $manager = $this->doctrine->getManager();
        $manager->persist($coffee);
    }

    $manager->flush();
}

Here are the Entity classes: Coffee:

<?php

namespace App\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * Coffee
 *
 * @ORM\Table(name="coffee", indexes={@ORM\Index(name="IDX_538529B3427EB8A5", columns={"request_id"}), @ORM\Index(name="IDX_538529B3651BF703", columns={"vmc_no"})})
 * @ORM\Entity
 */
class Coffee
{
    /**
     * @var int
     *
     * @ORM\Column(name="id", type="integer", nullable=false)
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="SEQUENCE")
     * @ORM\SequenceGenerator(sequenceName="coffee_id_seq", allocationSize=1, initialValue=1)
     */
    private $id;

    /**
     * @var \DateTime
     *
     * @ORM\Column(name="logdate", type="datetime", nullable=false)
     */
    private $logdate;

    /**
     * @var int
     *
     * @ORM\Column(name="amount", type="integer", nullable=false)
     */
    private $amount;

    /**
     * @var \Request
     *
     * @ORM\ManyToOne(targetEntity="Request")
     * @ORM\JoinColumns({
     *   @ORM\JoinColumn(name="request_id", referencedColumnName="id")
     * })
     */
    private $request;

    /**
     * @var \VmcCompany
     *
     * @ORM\ManyToOne(targetEntity="VmcCompany")
     * @ORM\JoinColumns({
     *   @ORM\JoinColumn(name="vmc_no", referencedColumnName="vmc_no")
     * })
     */
    private $vmcNo;

    

    public function getId(): ?int
    {
        return $this->id;
    }

    public function getLogdate(): ?\DateTimeInterface
    {
        return $this->logdate;
    }

    public function setLogdate(\DateTimeInterface $logdate): self
    {
        $this->logdate = $logdate;

        return $this;
    }

    public function getAmount(): ?int
    {
        return $this->amount;
    }

    public function setAmount(int $amount): self
    {
        $this->amount = $amount;

        return $this;
    }

    public function getRequest(): ?Request
    {
        return $this->request;
    }

    public function setRequest(?Request $request): self
    {
        $this->request = $request;

        return $this;
    }

    public function getVmcNo(): ?VmcCompany
    {
        return $this->vmcNo;
    }

    public function setVmcNo(?VmcCompany $vmcNo): self
    {
        $this->vmcNo = $vmcNo;

        return $this;
    }


}

VmcCompany:

<?php

namespace App\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * VmcCompany
 *
 * @ORM\Table(name="vmc_company")
 * @ORM\Entity
 */
class VmcCompany
{
    /**
     * @var int
     *
     * @ORM\Column(name="vmc_no", type="integer", nullable=false)
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="SEQUENCE")
     * @ORM\SequenceGenerator(sequenceName="vmc_company_vmc_no_seq", allocationSize=1, initialValue=1)
     */
    private $vmcNo;

    /**
     * @var \DateTime
     *
     * @ORM\Column(name="register_date", type="datetime", nullable=false)
     */
    private $registerDate;

    

    public function getVmcNo(): ?int
    {
        return $this->vmcNo;
    }

    public function getRegisterDate(): ?\DateTimeInterface
    {
        return $this->registerDate;
    }

    public function setRegisterDate(\DateTimeInterface $registerDate): self
    {
        $this->registerDate = $registerDate;

        return $this;
    }


}

I'm new to Symfony / Doctrine and so I guess I'm overseeing something, but just cannot find out what it is. Thanks for your help in advance.

Answer 1

If someone else runs into this problem:

You need to declare the id field in the database table as follows:

id integer NOT NULL GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,

The emphasis lies on BY DEFAULT instead of ALWAYS .

Otherwise Symfony runs into a conflict with Postgres while auto-incrementing.