5.1.10 Data Deletion

Overview

This chapter covers deleting data from a GridDB collection.

Delete data

Delete data from a collection with specifying a Row key.

List.1 Delete Data (CollectionDeleteRow.java)

            // Get Collection
            Collection weatherStationCol =
                    store.getCollection("weather_station", WeatherStation.class);

            // Delete Row
            boolean deleteSucceed = weatherStationCol.remove("1");
            System.out.println("Delete Succeed:" + deleteSucceed);

            System.out.println("ID\tName\t\t\tLongitude\tLatitude\tCamera");
            for (int i = 0; i < WeatherStationLogic.JP_PREFECTURE; i++) {
                // Retrieve row by key
                WeatherStation weatherStation = weatherStationCol.get(String.valueOf(i + 1));
                if (weatherStation != null) {
                    System.out.println(String.format("%-3s\t%-20s\t%-10s\t%-10s\t%-5s",
                            weatherStation.id, weatherStation.name, weatherStation.latitude,
                            weatherStation.longitude, weatherStation.hasCamera));
                } else {
                    System.out.println(String.format("ID:%s is not exist", (i + 1)));
                }
            }
            

• L.28: Delete a Row with specifying the measuring instrument ID using Container.remove(String) method. If the deletion was sucesseful, the return value is True.
• L.32-42: Display the retrieved data after the deletion.

Execution results are as follows:

List.2 Result

Delete Succeed:true
ID  Name        Longitude   Latitude    Camera
ID: 1 does not exist
2   Aomori-Aomori   40.82444    140.74      false
3   Iwate-Morioka   39.70361    141.1525    true
4   Miyagi-Sendai   38.26889    140.87194   false
5   Akita-Akita 39.71861    140.1025    true
(Snip)

Complete Source Code

Complete source code used in this sample can be downloaded from the following.

Download: griddb-delete.zip