So I am working with a legacy database using JPA/Hibernate. Our booleans are stored as a VARCHAR(5) with the values of either 'true' or 'false', This does not lend its self to using the built in Hibernate type or either yes_no or true_false.
I tried using Hibernates org.hibernate.usertype.UserType interface to create a user type. This almost worked. I was able to successfully read and write data. The problem was that if I had a query in which I want to statically use true or false I had to singe quote the true or false. See below for what did and did not work.
What I wanted
Select ss from StudentSupportSurvey ss where ss.stopNags = true
What I had to do
Select ss from StudentSupportSurvey ss where ss.stopNags = 'true'
UserType that worked
Notice that I did not implement UserType I instead extended AbstractSingleColumnStandardBasicType. In my opinion it is probably always better to override one of the abstract classes found in org.hibernate.type then to implement UserType.
package org.yfu.util.hibernate;
import java.io.Serializable;
import org.hibernate.dialect.Dialect;
import org.hibernate.type.AbstractSingleColumnStandardBasicType;
import org.hibernate.type.DiscriminatorType;
import org.hibernate.type.PrimitiveType;
import org.hibernate.type.StringType;
import org.hibernate.type.descriptor.java.BooleanTypeDescriptor;
import org.hibernate.type.descriptor.sql.VarcharTypeDescriptor;
public class TrueFalseBooleanUserType extends AbstractSingleColumnStandardBasicType<Boolean>
implements PrimitiveType<Boolean>, DiscriminatorType<Boolean>{
private static final long serialVersionUID = -2794554001044861116L;
public TrueFalseBooleanUserType() {
super(VarcharTypeDescriptor.INSTANCE, BooleanTypeDescriptor.INSTANCE);
}
@Override
public String getName() {
return "yfu_boolean";
}
public Class getPrimitiveClass() {
return boolean.class;
}
public Boolean stringToObject(String xml) throws Exception {
return fromString( xml );
}
public Serializable getDefaultValue() {
return Boolean.FALSE;
}
public String objectToSQLString(Boolean value, Dialect dialect) throws Exception {
return StringType.INSTANCE.objectToSQLString( value.booleanValue() ? "true" : "false", dialect );
}
}
This allowed me to right my query like this:
Select ss from StudentSupportSurvey ss where ss.stopNags = true
