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1package com.example.android.sunshine.app.data;
2
3import android.content.Context;
4import android.database.sqlite.SQLiteDatabase;
5import android.database.sqlite.SQLiteOpenHelper;
6
7import com.example.android.sunshine.app.data.WeatherContract.LocationEntry;
8import com.example.android.sunshine.app.data.WeatherContract.WeatherEntry;
9
10/** Manages a local database for weather data. */
11public class WeatherDbHelper extends SQLiteOpenHelper {
12
13    // If you change the database schema, you must increment the database version.
14    private static final int DATABASE_VERSION = 2;
15
16    static final String DATABASE_NAME = "weather.db";
17
18    public WeatherDbHelper(Context context) {
19        super(context, DATABASE_NAME, null, DATABASE_VERSION);
20    }
21
22    @Override
23    public void onCreate(SQLiteDatabase sqLiteDatabase) {
24        final String SQL_CREATE_WEATHER_TABLE =
25                "CREATE TABLE " + WeatherEntry.TABLE_NAME + " (" +
26                // Why AutoIncrement here, and not above?
27                // Unique keys will be auto-generated in either case.  But for weather
28                // forecasting, it's reasonable to assume the user will want information
29                // for a certain date and all dates *following*, so the forecast data
30                // should be sorted accordingly.
31                WeatherEntry._ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +
32
33                // the ID of the location entry associated with this weather data
34                WeatherEntry.COLUMN_LOC_KEY + " INTEGER NOT NULL, " +
35                WeatherEntry.COLUMN_DATE + " INTEGER NOT NULL, " +
36                WeatherEntry.COLUMN_SHORT_DESC + " TEXT NOT NULL, " +
37                WeatherEntry.COLUMN_WEATHER_ID + " INTEGER NOT NULL," +
38
39                WeatherEntry.COLUMN_MIN_TEMP + " REAL NOT NULL, " +
40                WeatherEntry.COLUMN_MAX_TEMP + " REAL NOT NULL, " +
41
42                WeatherEntry.COLUMN_HUMIDITY + " REAL NOT NULL, " +
43                WeatherEntry.COLUMN_PRESSURE + " REAL NOT NULL, " +
44                WeatherEntry.COLUMN_WIND_SPEED + " REAL NOT NULL, " +
45                WeatherEntry.COLUMN_DEGREES + " REAL NOT NULL, " +
46
47                // Set up the location column as a foreign key to location table.
48                " FOREIGN KEY (" + WeatherEntry.COLUMN_LOC_KEY + ") REFERENCES " +
49                LocationEntry.TABLE_NAME + " (" + LocationEntry._ID + "), " +
50
51                // To assure the application have just one weather entry per day
52                // per location, it's created a UNIQUE constraint with REPLACE strategy
53                " UNIQUE (" + WeatherEntry.COLUMN_DATE + ", " +
54                WeatherEntry.COLUMN_LOC_KEY + ") ON CONFLICT REPLACE);";
55
56        sqLiteDatabase.execSQL(SQL_CREATE_WEATHER_TABLE);
57
58        final String SQL_CREATE_LOCATION_TABLE =
59                "CREATE TABLE " + LocationEntry.TABLE_NAME + " (" +
60                LocationEntry._ID + " INTEGER PRIMARY KEY, " +
61                LocationEntry.COLUMN_LOCATION_SETTING + " TEXT UNIQUE NOT NULL, " +
62                LocationEntry.COLUMN_CITY_NAME + " TEXT NOT NULL, " +
63                LocationEntry.COLUMN_COORD_LAT + " REAL NOT NULL, " +
64                LocationEntry.COLUMN_COORD_LONG + " REAL NOT NULL);";
65
66        sqLiteDatabase.execSQL(SQL_CREATE_LOCATION_TABLE);
67
68
69    }
70
71    @Override
72    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int oldVersion, int newVersion) {
73        // This database is only a cache for online data, so its upgrade policy is
74        // to simply to discard the data and start over
75        // Note that this only fires if you change the version number for your database.
76        // It does NOT depend on the version number for your application.
77        // If you want to update the schema without wiping data, commenting out the next 2 lines
78        // should be your top priority before modifying this method.
79        sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + LocationEntry.TABLE_NAME);
80        sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + WeatherEntry.TABLE_NAME);
81        onCreate(sqLiteDatabase);
82    }
83}