5.1.9 Data Retrieval
Overview
This chapter covers retrieving data using the GridDB API.
Retrieve data
Retrieve data in a collection with specifying a Row key.
List.1 Data Read (WeatherStationLogic.java)// Get Collection CollectionweatherStationCol = store.getCollection("weather_station", WeatherStation.class); }
- L.24-25: Retrieve a collection by specifying a container name
List.2 Data Read by Row Key(CollectionRetrieve.java)
try { 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)); System.out.println (String.format("% - 3s \t% -20s \t% -10s \t% -10s \t% -5s", weatherStation.id, weatherStation.name, weatherStation.latitude, weatherStation.longitude, weatherStation.hasCamera)); } } Finally { // Close Connection weatherStationCol.close (); }
- L.31: Retrieve a Row with specifying the measuring instrument ID of the key.
Execution results are as follows.
ID Name Longitude Latitude Camera 1 Hokkaido-Sapporo 43.06417 141.34694 true 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: collection-retrieve.zip