private String writeDropForeignKeys() {
        StringBuilder sb = new StringBuilder();
        Table fromTable;

        ForeignNode node;
        for ( int keyNum = 0; keyNum < foreignNodeList.size(); keyNum++ ) {
            node = foreignNodeList.get( keyNum );
            fromTable = tableMap.get( node.getFromTable() );
            sb.append( "ALTER TABLE " + fromTable.getTableName() );
            sb.append( " DROP CONSTRAINT FK_" + fromTable.getTableName() + "_" + keyNum + ";\n" );
        }
        return sb.toString();
    }