app/src/main/java/uk/me/njae/sunshine/data/WeatherDbHelper.java

   1 package uk.me.njae.sunshine.data;
   2
   3 import android.content.Context;
   4 import android.database.sqlite.SQLiteDatabase;
   5 import android.database.sqlite.SQLiteOpenHelper;
   6
   7 import uk.me.njae.sunshine.data.WeatherContract.LocationEntry;
   8 import uk.me.njae.sunshine.data.WeatherContract.WeatherEntry;
   9
  10
  11 /**
  12  * Manages a local database for weather data.
  13  */
  14 public class WeatherDbHelper extends SQLiteOpenHelper {
  15
  16     // If you change the database schema, you must increment the database version.
  17     private static final int DATABASE_VERSION = 1;
  18
  19     public static final String DATABASE_NAME = "weather.db";
  20
  21     public WeatherDbHelper(Context context) {
  22         super(context, DATABASE_NAME, null, DATABASE_VERSION);
  23     }
  24
  25     @Override
  26     public void onCreate(SQLiteDatabase sqLiteDatabase) {
  27         // Create a table to hold locations.  A location consists of the string supplied in the
  28         // location setting, the city name, and the latitude and longitude
  29         final String SQL_CREATE_LOCATION_TABLE = "CREATE TABLE " + LocationEntry.TABLE_NAME + " (" +
  30                 LocationEntry._ID + " INTEGER PRIMARY KEY," +
  31                 LocationEntry.COLUMN_LOCATION_SETTING + " TEXT UNIQUE NOT NULL, " +
  32                 LocationEntry.COLUMN_CITY_NAME + " TEXT NOT NULL, " +
  33                 LocationEntry.COLUMN_COORD_LAT + " REAL NOT NULL, " +
  34                 LocationEntry.COLUMN_COORD_LONG + " REAL NOT NULL, " +
  35                 "UNIQUE (" + LocationEntry.COLUMN_LOCATION_SETTING +") ON CONFLICT IGNORE"+
  36                 " );";
  37
  38         final String SQL_CREATE_WEATHER_TABLE = "CREATE TABLE " + WeatherEntry.TABLE_NAME + " (" +
  39                 // Why AutoIncrement here, and not above?
  40                 // Unique keys will be auto-generated in either case.  But for weather
  41                 // forecasting, it's reasonable to assume the user will want information
  42                 // for a certain date and all dates *following*, so the forecast data
  43                 // should be sorted accordingly.
  44                 WeatherEntry._ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +
  45
  46                 // the ID of the location entry associated with this weather data
  47                 WeatherEntry.COLUMN_LOC_KEY + " INTEGER NOT NULL, " +
  48                 WeatherEntry.COLUMN_DATETEXT + " TEXT NOT NULL, " +
  49                 WeatherEntry.COLUMN_SHORT_DESC + " TEXT NOT NULL, " +
  50                 WeatherEntry.COLUMN_WEATHER_ID + " INTEGER NOT NULL," +
  51
  52                 WeatherEntry.COLUMN_MIN_TEMP + " REAL NOT NULL, " +
  53                 WeatherEntry.COLUMN_MAX_TEMP + " REAL NOT NULL, " +
  54
  55                 WeatherEntry.COLUMN_HUMIDITY + " REAL NOT NULL, " +
  56                 WeatherEntry.COLUMN_PRESSURE + " REAL NOT NULL, " +
  57                 WeatherEntry.COLUMN_WIND_SPEED + " REAL NOT NULL, " +
  58                 WeatherEntry.COLUMN_DEGREES + " REAL NOT NULL, " +
  59
  60                 // Set up the location column as a foreign key to location table.
  61                 " FOREIGN KEY (" + WeatherEntry.COLUMN_LOC_KEY + ") REFERENCES " +
  62                 LocationEntry.TABLE_NAME + " (" + LocationEntry._ID + "), " +
  63
  64                 // To assure the application have just one weather entry per day
  65                 // per location, it's created a UNIQUE constraint with REPLACE strategy
  66                 " UNIQUE (" + WeatherEntry.COLUMN_DATETEXT + ", " +
  67                 WeatherEntry.COLUMN_LOC_KEY + ") ON CONFLICT REPLACE);";
  68
  69         sqLiteDatabase.execSQL(SQL_CREATE_LOCATION_TABLE);
  70         sqLiteDatabase.execSQL(SQL_CREATE_WEATHER_TABLE);
  71     }
  72
  73     @Override
  74     public void onUpgrade(SQLiteDatabase sqLiteDatabase, int oldVersion, int newVersion) {
  75         sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + LocationEntry.TABLE_NAME);
  76         sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + WeatherEntry.TABLE_NAME);
  77         onCreate(sqLiteDatabase);
  78     }
  79 }