--- a/src/test/java/jp/ac/u_ryukyu/ie/cr/JDBCSqliteTest.java	Thu Dec 01 03:46:38 2016 +0900
+++ b/src/test/java/jp/ac/u_ryukyu/ie/cr/JDBCSqliteTest.java	Thu Dec 01 03:54:30 2016 +0900
@@ -13,6 +13,10 @@
         try {
             Class.forName("org.sqlite.JDBC");
 
+            /*
+            - create db file on working directory. name ex. @windows -> C:/workingspace/test.db", @mac -> "jdbc:sqlite:workingspace/test.db
+            - do not need create table and columns in Sqlite console.
+             */
             Connection conn = DriverManager.getConnection("jdbc:sqlite:C:/sqlite/database.db");
 
             Statement stmt = conn.createStatement();
@@ -35,6 +39,7 @@
             ResultSet get_user = stmt.executeQuery("select * from user where name=\'Kono\'");
             ResultSet rs = stmt.executeQuery("with recursive n as (select * from user where id="+ get_user.getInt("id") +" union all select user.* from user, n where user.parent_id = n.id) select * from n");
 
+            // get all children from root.
             while (rs.next()){
                 System.out.println("User ->  " + rs.getString("name"));
             }