Error executing DDL alter table if exists task.city

The error Error executing DDL "alter table if exists task.city add constraint FKtjrg7h2j3ehgycr3usqjgnc2u foreign key (id) references task.house" via JDBC Statement" I Don't understand how to solve it, I was already looking for a solution, but I check my database and Entity, everything is correct. I created the database from scratch myself. I work in Postgresql. Added the error log.

Properties

spring.datasource.url=jdbc:postgresql://localhost:5432/innotechnum
spring.datasource.username=***
spring.datasource.password=***
spring.datasource.driver-class-name=org.postgresql.Driver
spring.jpa.database=postgresql
spring.jpa.hibernate.ddl-auto=update
spring.jpa.database-platform=org.hibernate.dialect.PostgreSQL10Dialect
spring.jpa.properties.hibernate.jdbc.lob.non_contextual_creation=true
spring.jpa.open-in-view= true
spring.jpa.show-sql=true

City

@Data
@Entity
@Table(name = "city", schema = "task")
public class City {

    @Id
    @GeneratedValue(strategy= GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @Column(name = "id_region", nullable = false)
    private Integer id_region;
    @Column(name = "name", nullable = false)
    private String name;
}

house

@Data
@Entity
@Table (name = "house", schema = "task")
public class House {

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;
    
    @OneToMany(cascade = {CascadeType.DETACH, CascadeType.MERGE, CascadeType.PERSIST,
            CascadeType.REFRESH
    })
    @JoinColumn(name = "id")
    private Set<City> city;
    
    @OneToMany(mappedBy = "house")
    private Set<Contract> contract;

    @Column(name = "id_landlord", nullable = false)
    private Long id_landlord;
    @Column(name = "outside", nullable = false)
    private String outside;
    @Column(name = "rooms", nullable = false)
    private Integer rooms;
    @Column(name = "price", nullable = false)
    private Double price;
    @Column(name = "description", nullable = false)
    private String description;
}

LOGS:

org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "alter table if exists task.city add constraint FKtjrg7h2j3ehgycr3usqjgnc2u foreign key (id) references task.house" via JDBC Statement
	at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67) ~[hibernate-core-5.4.20.Final.jar:5.4.20.Final]
	at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlString(AbstractSchemaMigrator.java:559) ~[hibernate-core-5.4.20.Final.jar:5.4.20.Final]
	at
	...

This is the code that Postgresql gives me:

CREATE TABLE task.city
(
    id integer NOT NULL DEFAULT nextval('task.city_id_seq'::regclass),
    id_region integer NOT NULL,
    name character varying(250) COLLATE pg_catalog."default" NOT NULL,
    CONSTRAINT city_pkey PRIMARY KEY (id)
)

TABLESPACE pg_default;

ALTER TABLE task.city
    OWNER to root;

You should not use unidirectional @OneToMany association. Try to add the

@ManyToOne(fetchType = LAZY)
@JoinColumn(name = "house_id")
private House house;

to the City class.

P.S. Do you sure you need one-to-many association from house to city but not vice versa? City may have many houses, but house belongs to the particular city.

Hmm, try

public class House {
  ...
  @ManyToOne(optional = false)
  @JoinColumn(name = "city_id", referencedColumnName = "id")
  private Set<City> city;
  ...
}

btw,

• should not use @Data lombok in an entity class
• spring.jpa.hibernate.ddl-auto=update can change update to none. You should manage schema on your own.