I have a MyDBAdapter class, that can do selects, but I also need to do
DELETE FROM user Where email="given value by variable String"
I don’t know how to do deletes on MyDBAdapter with android, I’m very newbie with this, can someone complete my class adding that function to delete users by email please?
This is my class:
public class MyDbAdapter {
private static final String TAG = "NotesDbAdapter";
private DatabaseHelper mDbHelper;
private SQLiteDatabase mDb;
private static final String DATABASE_NAME = "gpslocdb";
private static final String PERMISSION_TABLE_CREATE = "CREATE TABLE permission ( fk_email1 varchar, fk_email2 varchar, validated tinyint, hour1 time default '08:00:00', hour2 time default '20:00:00', date1 date, date2 date, weekend tinyint default '0', fk_type varchar, PRIMARY KEY (fk_email1,fk_email2))";
private static final String USER_TABLE_CREATE = "CREATE TABLE user ( email varchar, password varchar, fullName varchar, mobilePhone varchar, mobileOperatingSystem varchar, PRIMARY KEY (email))";
private static final int DATABASE_VERSION = 2;
private final Context mCtx;
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("DROP TABLE IF EXISTS user");
db.execSQL("DROP TABLE IF EXISTS permission");
db.execSQL(PERMISSION_TABLE_CREATE);
db.execSQL(USER_TABLE_CREATE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
//db.execSQL("DROP TABLE IF EXISTS user");
//db.execSQL("DROP TABLE IF EXISTS permission");
//onCreate(db);
}
@Override
public void onOpen(SQLiteDatabase db) {
super.onOpen(db);
//onCreate(db);
}
public void clearDb(SQLiteDatabase db) {
db.execSQL("DROP TABLE IF EXISTS user");
db.execSQL("DROP TABLE IF EXISTS permission");
onCreate(db);
}
}
/**
* Constructor - takes the context to allow the database to be
* opened/created
*
* @param ctx the Context within which to work
*/
public MyDbAdapter(Context ctx) {
this.mCtx = ctx;
}
/**
* Open the database. If it cannot be opened, try to create a new
* instance of the database. If it cannot be created, throw an exception to
* signal the failure
*
* @return this (self reference, allowing this to be chained in an
* initialization call)
* @throws SQLException if the database could be neither opened or created
*/
public MyDbAdapter open() throws SQLException {
mDbHelper = new DatabaseHelper(mCtx);
mDb = mDbHelper.getWritableDatabase();
return this;
}
public void close() {
//clearDB();
mDbHelper.close();
}
public long createUser(String email, String password, String fullName, String mobilePhone, String mobileOperatingSystem) {
ContentValues initialValues = new ContentValues();
initialValues.put("email", email);
initialValues.put("password", password);
initialValues.put("fullName", fullName);
initialValues.put("mobilePhone", mobilePhone);
initialValues.put("mobileOperatingSystem", mobileOperatingSystem);
return mDb.insert("user", null, initialValues);
}
public long createPermission(String email1, String email2, String validated, String hour1, String hour2,
String date1, String date2, String weekend, String fk_type) {
ContentValues initialValues = new ContentValues();
initialValues.put("fk_email1", email1);
initialValues.put("fk_email2", email2);
initialValues.put("validated", validated);
initialValues.put("hour1", hour1);
initialValues.put("hour2", hour2);
initialValues.put("date1", date1);
initialValues.put("date2", date2);
initialValues.put("weekend", weekend);
initialValues.put("fk_type", fk_type);
return mDb.insert("permission", null, initialValues);
}
public void clearDB() {
mDbHelper.clearDb(mDb);
}
public Cursor fetchAllUsers() {
return mDb.query("user", new String[]{"email", "password", "fullName", "mobilePhone", "mobileOperatingSystem"}, null, null, null, null, null);
}
public Cursor fetchAllPermissions() {
return mDb.query("permission", new String[]{"fk_email1", "fk_email2", "validated", "hour1", "hour2", "date1", "date2", "weekend", "fk_type"}, null, null, null, null, null);
}
public Cursor fetchUser(String email) throws SQLException {
Cursor mCursor = mDb.query(true, "user", new String[]{"email", "password", "fullName", "mobilePhone", "mobileOperatingSystem"}
, "email" + "=" + email, null, null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
public void deleteUser(String email) throws SQLException {
Delete From permission Where fk_email1 = 'pablo@upv.es' and fk_email2 = 'fanny@test.es'
}
public List<Friend> retrieveAllFriends() {
List<Friend> friends = new ArrayList<Friend>();
Cursor result = fetchAllUsers();
if (result.moveToFirst()) {
do {
friends.add(new Friend(result.getString(result.getColumnIndexOrThrow("email")), result.getString(result.getColumnIndexOrThrow("password")), result.getString(result.getColumnIndexOrThrow("fullName")), result.getString(result.getColumnIndexOrThrow("mobilePhone")), result.getString(result.getColumnIndexOrThrow("mobileOperatingSystem"))));
} while (result.moveToNext());
}
return friends;
}
public List<Permission> retrieveAllPermissions() {
List<Permission> permissions = new ArrayList<Permission>();
Cursor result = fetchAllPermissions();
if (result.moveToFirst()) {
do {
permissions.add(new Permission(result.getString(result.getColumnIndexOrThrow("fk_email1")),
result.getString(result.getColumnIndexOrThrow("fk_email2")),
Integer.parseInt(result.getString(result.getColumnIndexOrThrow("validated"))),
result.getString(result.getColumnIndexOrThrow("hour1")),
result.getString(result.getColumnIndexOrThrow("hour2")),
result.getString(result.getColumnIndexOrThrow("date1")),
result.getString(result.getColumnIndexOrThrow("date2")),
Integer.parseInt(result.getString(result.getColumnIndexOrThrow("weekend"))),
result.getString(result.getColumnIndexOrThrow("fk_type"))));
} while (result.moveToNext());
}
return permissions;
}
}
mDb.delete(DATABASE_NAME, "email" + "=" + value_to_delete, null);