I set SybaseDialect's supportsNotNullUnique to false, but SchemaExport is still creating tables with "not null unique" in them.

Possible fix...

org.hibernate.mapping.Table#sqlCreateString has the following check:

boolean useUniqueConstraint = col.isUnique() && ( !col.isNullable() || dialect.supportsNotNullUnique() );

Should that "!" be there? It seems that "unique" should be added iff 1.) col is unique and 2.) col IS nullable or supportsNotNullUnique.