/*
 * This transformation is uni-directional in direction "rdbms" and maps classes in packages to tables in schemas.
 * It is based upon the example in the official QVT specification at http://www.omg.org/cgi-bin/apps/doc?ptc/05-11-01.pdf.
 */

transformation uml2rdbms  ( uml : UML , rdbms : RDBMS ) {

	key RDBMS::Table {name, schema};
	key RDBMS::Column {name, owner};
	key RDBMS::Key {name, owner};

	-- map each package to a schema
        top relation PackageToSchema {
	  
	  pn : String;
	  
	  checkonly domain uml p : UML::Package {
	    name = pn
	  };
	  
	  enforce domain rdbms s : RDBMS::Schema {
	    name = pn
	  };
	  
	}
	
	
	-- map each persistent class to a table
	top relation ClassToTable {
	  
	  cn, prefix : String;
	  
	  checkonly domain uml c : UML::Class {
	    namespace = p : UML::Package {
	    },
	    kind = 'Persistent',
	    name = cn
	  };
	  
	  enforce domain rdbms t : RDBMS::Table {
	    schema = s : RDBMS::Schema {
	    },
	    name = cn,
	    column = cl : RDBMS::Column {
	      name = 'TID',
	      typeT = 'NUMBER'
	    },
	    keyK = k : RDBMS::Key {
	    	name = 'PK',
	      	column = cl
	    }
	  };
	  
	  when {
	    PackageToSchema(p, s);
	  }
	  
	  where {
	    AttributeToColumn(c, t, prefix);

            = (prefix) ('EMPTY');
	    --prefix = '';
	  }
	  
	}
	
		
	relation AttributeToColumn {

	  an, pn, cn, sqltype : String;

	  primitive domain prefix : String;
	  
	  checkonly domain uml c : UML::Class {
	    attribute = a : UML::Attribute {
	      name = an,
	      typeT = p : UML::PrimitiveDataType {
	        name = pn
	      }
	    }
	  };
	  
	  enforce domain rdbms t : RDBMS::Table {
	    column = cl : RDBMS::Column {
	      name = cn,
	      typeT = sqltype
	    }
	  };
	  
	  where {
	    --cn = if prefix = '' then an else prefix + an endif;
  
            or ( and (= (prefix) ('EMPTY')) (= (cn) (an)) )
               ( and (not (= (prefix) ('EMPTY'))) (= (cn) (prefix + an)) );

            -- sqltype = if pn = 'INTEGER' then 'NUMBER' else if pn = 'BOOLEAN' then 'BOOLEAN' else 'VARCHAR' endif endif;
            
            or (or ( and (= (pn) ('INTEGER')) (= (sqltype) ('NUMBER') ) )
                   ( and (= (pn) ('BOOLEAN')) (= (sqltype) ('BOOLEAN')) ))
               ( and (and (not (= (pn) ('INTEGER'))) (not (= (pn) ('BOOLEAN')))) (= (sqltype) ('VARCHAR')) );

	  }
	  
	}
		
}