Unsuccessful: alter table XXX drop constraint YYY in Hibernate/JPA/HSQLDB standalone

Question

I am trying to run some Hibernate/JPA examples using an in-memory HSQL DB. The error message I get is the following:

13:54:21,427 ERROR SchemaExport:425 - HH         


        

Answer 1

The Solution @Sander provided above works for MYSQL too. Just extend MySQL5InnoDBDialect instead like below:

import org.hibernate.dialect.MySQL5InnoDBDialect;

public class ImprovedMySQLDialect extends MySQL5InnoDBDialect {
    @Override
    public String getDropSequenceString(String sequenceName) {
        // Adding the "if exists" clause to avoid warnings
        return "drop sequence if exists " + sequenceName;
    }

    @Override
    public boolean dropConstraints() {
        // We don't need to drop constraints before dropping tables, that just leads to error
        // messages about missing tables when we don't have a schema in the database
        return false;
    }
}

Then in your datasource file change the following line:

dialect = org.hibernate.dialect.MySQL5InnoDBDialect

to

dialect = my.package.name.ImprovedMySQLDialect