How to save data received from Arduino board in Android using SQL database?

Ok here's something that you could adapt, it shows how to create database and table(s) and then how to insert data and also a how to do a check check that the data exists.

Virtually all of the code is in the SQLiteOpenHelp subclass, which for my convenience I have called so46375780DBHelper (you would very likely rename this) this should be in a file named so46375780DBHelper.java :-

public class so46375780DBHelper extends SQLiteOpenHelper {

    public static final String DBNAME = "airquality";
    public static final int DBVERSION = 1;
    public static final String READINGS_TBL = "air_readings";
    public static final String READINGID_COL = "_id";
    public static final String READINGTIMESTAMP_COL = "timestamp";
    public static final String READINGLOCATION_COL = "location";
    public static final String READINGSENSOR1_COL = "sensor1";
    public static final String READINGSENSOR2_COL = "sensor2";
    public static final String READINGSENSOR3_COL = "sensor3";
    public static final String READINGAIRQLTY_COL = "airquality";

    SQLiteDatabase db;

    // SQL to create the table
    String tblcrtsql = "CREATE TABLE " + READINGS_TBL + "(" +
            READINGID_COL + " INTEGER PRIMARY KEY, " + // unqiue identifier
            READINGTIMESTAMP_COL + " INTEGER, " +
            READINGLOCATION_COL + " TEXT, " +
            READINGSENSOR1_COL + " TEXT, " +
            READINGSENSOR2_COL + " TEXT, " +
            READINGSENSOR3_COL + " TEXT, " +
            READINGAIRQLTY_COL + " TEXT" +
            ")";

    // Database Helper Constructor
    so46375780DBHelper(Context context) {
        super(context, DBNAME, null, DBVERSION);
        db = this.getWritableDatabase();    // Open the database
    }

    @Override
    // Called when Database is openbed when it doesn't already exist
    // ^^^^^^^^ IMPORTANT to note ^^^^^^^^
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(tblcrtsql); // Create the table(s)
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldversion, int newversio) {

    }

    public boolean insertReading(String location,
                                 String sensor1,
                                 String sensor2,
                                 String sensor3,
                                 String airquality) {
        ContentValues cv = new ContentValues();
        cv.put(READINGTIMESTAMP_COL,
                Long.toString(
                System.currentTimeMillis()
                )
        );
        cv.put(READINGLOCATION_COL,location);
        cv.put(READINGSENSOR1_COL,sensor1);
        cv.put(READINGSENSOR2_COL,sensor2);
        cv.put(READINGSENSOR3_COL,sensor3);
        cv.put(READINGAIRQLTY_COL,airquality);
        return (db.insert(READINGS_TBL,null,cv) < 1);
    }

    public void showAllDataToLog() {

        //get all rows eqv to SELECT * FROM air_readings;
        Cursor csr = db.query(READINGS_TBL,null,null,null,null,null,null);
        // Traverse the cursor
        while (csr.moveToNext()) {
            String rowinfo = "Row " +
                    csr.getPosition() +
                    " of " +
                    csr.getCount() + ".";
            for (int i=0; i < csr.getColumnCount();i++) {
                rowinfo = rowinfo +
                        "\n\t Column=" + csr.getColumnName(i) +
                        "\t Value=" + csr.getString(i);
            }
            Log.d("DBINFO",rowinfo);
        }
        csr.close(); // Should always close cursor when finished with them
    }
}

In brief you have the

• class variable declarations,
• the contructor
• overidden methods onCreate and onUpgrade (both required, but not necessarily required to do anything)
• insertReadings method that uses the SQLite update method, which utilises a ContentValues object for the column/value pairs. This method will return a value of 1 or greater (the rowid which equates to the _id column), if the insert was successful.
• showAllDataToLog just there to check the data exists.

Next it's just a matter of 2 steps to enable insertion of data, these steps are placed in the class (or classes) where the data will be inserted.

• 1 Create an instance of the SQLiteOpenHelper subclass e.g. :-

  so46375780DBHelper dbhlpr = new so46375780DBHelper(this);
  

• 2 Use the insertReading method to insert some data e.g. :-

  // Insert a row
  dbhlpr.insertReading(
          "001,345",          //coords
          "76.5",             // sensor 1 reading
          "57.3",             // sensor 2 reading
          "12.6",             // sensor 2 reading
          "LOUSY"             // air quality
  );
  

Note! made up readings, also you may wish to alter the method to utilise more relevant types (note SQlite is extremely flexible with types, with few limitations you can store any type if value in any type of column). However, when it comes to extracting the data from a Cursor you should chose the most appropriate get????? method (below only the getString method is used which is Ok for just checking the existence).

The following code will list the data to the log, it is only intended for initial re-assurance that the inserts are working :-

    // Check data (writes to the log)
    dbhlpr.showAllDataToLog();