org.postgresql.util.PSQLException: ERROR: column user0_.id does not exist - Hibernate

Question

I have a model class that is mapped to a postgres database using hibernate. My model class is:

@Entity
@Table(name=\"USER\")
public class User {

    @Id 
    @G         


        

Answer 1

Solution

In PostgreSQL you have to specify the name of schema like so :

@Table(name="table_name", schema = "myapp")
                          ^^^^^^^^^^^^^^^^

Long Story

you got this error :

org.postgresql.util.PSQLException: ERROR: column user0_.id does not exist

because when you create a database in PostgreSQL, it create a default schema named public, so when you don't specify the name in the Entity then Hibernate will check automatically in the public schema.

---

Good practices

1. Don't use Upper letters in the name of database, schema, tables or columns in PostgreSQL. Else you should to escape this names with quotes, and this can cause Syntax errors, so instead you can use :

@Table(name="table_name", schema = "schame_name")
             ^^^^^^^^^^             ^^^^^^^^^^^

2. the keyword USER is reserved keyword in PostgreSQL take a look at

+----------+-----------+----------+-----------+---------+
| Key Word |PostgreSQL |SQL:2003  | SQL:1999  | SQL-92  |
+----------+-----------+----------+-----------+---------+
|  ....        ....       ....       ....       ....    |
+----------+-----------+----------+-----------+---------+
| USER     |  reserved |reserved  | reserved  | reserved|
+----------+-----------+----------+-----------+---------+

3. to difference between Dto and Entity its good practice to use Entity in the end of the name of your Entity for example UserEntity

Answer 2

For people getting this exception ,In postgres Whenever you write an Entity Class try to associate it with the correct schema (where your table is present), like this:

@Entity
@Table(name = "user", schema = "users_details")
public class User implements Serializable{

    @Column(name = "id")
    Long id;    //long is not recommended

   // Other data
}

As @YCF_L has said Don't use Upper_case letters in a table name or column name otherwise you will get this exception.

This convention becomes more important when their is a scenario where you have to auto generate the tables from entity classes or vice-versa.

Answer 3

Try Dropping the table from pg admin console (drop table schema_name.table_name)and make sure your entity class is proper annotated.For example @Table(name = "table_name", schema = "schema_name") on entity class

Answer 4

Should add schema name on the Entity class. For this example, when the schema name is public

@Table(name = "user", schema = "public")

See the PostgreSQL Admin view below

See here for more about SpringBoot Java and Postgre SQL connectivity: https://cmsoftwaretech.wordpress.com/2020/04/25/springboot-thymleaf-using-postgresql/

Answer 5

I obtained using general names like user are making troubles in the app.

I got the same issue as reported here with the following simple entity.

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.SequenceGenerator;

@Entity
public class User implements Serializable {

    private static final long serialVersionUID = 6843302791607583447L;

    @Id
    @SequenceGenerator(name = "user_id_seq", sequenceName = "user_id_seq", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "user_id_seq")
    private Long id;

    @Column
    private String name;

    @Column
    private String password;

    @Override
    public String toString() {
        return name;
    }

    public Long getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public void setName(final String name) {
        this.name = name;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(final String password) {
        this.password = password;
    }

}

All i did was renaming the entity from User to Sessionxuser (and renaming the datatable from user to sessionxuser to fix this issue.

Schema was still public.

Since pre- or postfix some names like mycoolappuser or usermycoolapp to avoid troubles like this.

Find below a list with reserved keywords and literals preventing using as table, column, and further customized names.

https://www.postgresql.org/docs/8.1/sql-keywords-appendix.html

In this case user is preserved for PostgreSQL, SQL:2003, SQL:1999 and SQL-92.

Answer 6

Use: @GeneratedValue(strategy = GenerationType.IDENTITY)

In your POJO class Id Field. This thing solved my error.