Map a tinyint as boolean hibernate

Question

I have a BOOLEAN type in a MySQL table (TINYINT(1)) and I'm trying to map the boolean field in an entity but this generates an exception:

org.hibernate.HibernateException: Wrong column type in maegul.users for column admin. Found: bit, expected: boolean

I changed the field in my entity to byte and make the respective changes so it acts a boolean, and I get:

org.hibernate.HibernateException: Wrong column type in maegul.users for column admin. Found: bit, expected: tinyint

I tried using the @Type annotation on the field:

@Type(type = "org.hibernate.type.NumericBooleanType")

but I get:

org.hibernate.HibernateException: Wrong column type in maegul.users for column admin. Found: bit, expected: integer

Answer 1

From what I read here :

org.hibernate.HibernateException: Wrong column type in maegul.users for column admin. Found: bit, expected: integer

It seems Hibernate is expecting an integer and got a bit.

Which mean your annotation is now correct :

@Type(type = "org.hibernate.type.NumericBooleanType") 

But maybe it has updated your database to set as Bit instead of integer, thus the error.

If you really need a TinyInt, you can use @Type AND @Column, to set as Integer, of type TinyInt :

@Column(columnDefinition = "TINYINT") @Type(type = "org.hibernate.type.NumericBooleanType") public boolean admin = true; 

Answer 2

Better use BIT(1) instead of TINYINT(1)

@Column(nullable = false, columnDefinition = "BIT", length = 1)
private boolean flag = false;

Answer 3

You can do it from Dialect which will not require tedious col level annotation at all places:

import org.hibernate.Hibernate;
import org.hibernate.dialect.PostgreSQLDialect;
import java.sql.Types;

public class PostgresCustomConversionDialect extends PostgreSQLDialect {

    public PostgresCustomConversionDialect() {
        super();
        this.registerColumnType( Types.BIT, "numeric(1, 0)" );
        this.registerColumnType( Types.BOOLEAN, "numeric(1, 0)" );
    }

    public String toBooleanValueString(boolean bool) {
        return bool ? "1" : "0";
    }

}

Then use this custom dialect as postgres dialect in - "hibernate.dialect"