MJB MJB - 20 days ago 11
Android Question

Adding a second table in a database

This is my first post! I hope you can help me out! :-)

I used the code provided by the NotePadExample from the developers doc to create a database. Now I want to add a second table to store different data. I can add notes without a problem, and the notes table is created in a similar way as my routes table is. I simply "copied" and edited the given code, but when I try to insert into the new table I get an error saying:


"0ERROR/Database(370): android.database.sqlite.SQLiteException: no such table: routes: , while compiling: INSERT INTO routes(line, arrival, duration, start) VALUES(?, ?, ?, ?);"


Can someone please take quick look at my DbAdapter class, especially the onCreate() method. and give me a hint or a solution? I really don't see any problem. My code compiles without any errors..

CODE:



public class DbAdapter {

public static final String KEY_FROM = "title";
public static final String KEY_TO = "body";
public static final String KEY_ROWID = "_id";

public static final String KEY_START = "start";
public static final String KEY_ARRIVAL = "arrival";
public static final String KEY_LINE = "line";
public static final String KEY_DURATION = "duration";

private static final String DATABASE_NAME = "data";
private static final String DATABASE_NOTESTABLE = "notes";
private static final String DATABASE_ROUTESTABLE = "routes";

private static final String TAG = "DbAdapter";
private DatabaseHelper mDbHelper;
private SQLiteDatabase mDb;

/**
* Database creation sql statement
*/
private static final String DATABASE_CREATE_NOTES =
"create table notes (_id integer primary key autoincrement, "
+ "title text not null, body text not null)";

private static final String DATABASE_CREATE_ROUTES =
"create table routes (_id integer primary key autoincrement, "
+ "start , arrival , "
+ "line , duration );";

private static final int DATABASE_VERSION = 3;

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(DATABASE_CREATE_NOTES);
Log.d(TAG, "created notes table");

db.execSQL(DATABASE_CREATE_ROUTES);
Log.d(TAG, "created routes table");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS notes");
db.execSQL("DROP TABLE IF EXISTS routes");
onCreate(db);
}
}

/**
* Constructor - takes the context to allow the database to be
* opened/created
*
* @param ctx the Context within which to work
*/
public DbAdapter(Context ctx) {
this.mCtx = ctx;
}

/**
* Open the notes 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 DbAdapter open() throws SQLException {
mDbHelper = new DatabaseHelper(mCtx);
mDb = mDbHelper.getWritableDatabase();
return this;
}

public void close() {
mDbHelper.close();
}


/**
* Create a new note using the title and body provided. If the note is
* successfully created return the new rowId for that note, otherwise return
* a -1 to indicate failure.
*
* @param title the title of the note
* @param body the body of the note
* @return rowId or -1 if failed
*/
public long createNote(String title, String body) {

ContentValues initialValues = new ContentValues();
initialValues.put(KEY_FROM, title);
initialValues.put(KEY_TO, body);

return mDb.insert(DATABASE_NOTESTABLE, null, initialValues);
}

/**
* Create a new route using the title and body provided. If the route is
* successfully created return the new rowId for that route, otherwise return
* a -1 to indicate failure.
*
* @param start the start time of the route
* @param arrival the arrival time of the route
* @param line the line number of the route
* @param duration the routes duration
* @return rowId or -1 if failed
*/

public long createRoute(String start, String arrival, String line, String duration){

ContentValues initialValues = new ContentValues();
initialValues.put(KEY_START, start);
initialValues.put(KEY_ARRIVAL, arrival);
initialValues.put(KEY_LINE, line);
initialValues.put(KEY_DURATION, duration);

return mDb.insert(DATABASE_ROUTESTABLE, null, initialValues);
}

/**
* Delete the note with the given rowId
*
* @param rowId id of note to delete
* @return true if deleted, false otherwise
*/
public boolean deleteNote(long rowId) {
return mDb.delete(DATABASE_NOTESTABLE, KEY_ROWID + "=" + rowId, null) > 0;
}

/**
* Return a Cursor over the list of all notes in the database
*
* @return Cursor over all notes
*/
public Cursor fetchAllNotes() {
return mDb.query(DATABASE_NOTESTABLE, new String[] {KEY_ROWID, KEY_FROM,
KEY_TO}, null, null, null, null, null);
}

/**
* Return a Cursor over the list of all routes in the database
*
* @return Cursor over all routes
*/
public Cursor fetchAllRoutes() {
return mDb.query(DATABASE_ROUTESTABLE, new String[] {KEY_ROWID, KEY_START,
KEY_ARRIVAL, KEY_LINE, KEY_DURATION}, null, null, null, null, null);
}

/**
* Return a Cursor positioned at the note that matches the given rowId
*
* @param rowId id of note to retrieve
* @return Cursor positioned to matching note, if found
* @throws SQLException if note could not be found/retrieved
*/
public Cursor fetchNote(long rowId) throws SQLException {
Cursor mCursor =
mDb.query(true, DATABASE_NOTESTABLE, new String[] {KEY_ROWID,
KEY_FROM, KEY_TO}, KEY_ROWID + "=" + rowId, null,
null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;

}

/**
* Return a Cursor positioned at the route that matches the given rowId
*
* @param rowId id of route to retrieve
* @return Cursor positioned to matching route
* @throws SQLException if note could not be found/retrieved
*/
public Cursor fetchRoute(long rowId) throws SQLException {
Cursor mCursor =
mDb.query(true, DATABASE_ROUTESTABLE, new String[] {KEY_ROWID,
KEY_START, KEY_ARRIVAL, KEY_LINE, KEY_DURATION}, KEY_ROWID + "=" + rowId, null,
null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;

}

/**
* Update the note using the details provided. The note to be updated is
* specified using the rowId, and it is altered to use the title and body
* values passed in
*
* @param rowId id of note to update
* @param title value to set note title to
* @param body value to set note body to
* @return true if the note was successfully updated, false otherwise
*/
public boolean updateNote(long rowId, String title, String body) {
ContentValues args = new ContentValues();
args.put(KEY_FROM, title);
args.put(KEY_TO, body);
return mDb.update(DATABASE_NOTESTABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
}

public void deleteRoutesTable(SQLiteDatabase db){
db.delete("routes", null, null);
}
}


ADD



I want to implement a method like

public void deleteTableRoutes(SQLiteDataBase db){
db.delete("routes", null, null);
}


My problem: I want to call this function from a point where I have no reference to my db (as far as I know) to pass as an argument for my deleteTableRoutes(SQLiteDataBase) ...

MJB MJB
Answer

Instead of:

@Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                + newVersion + ", which will destroy all old data");
        db.execSQL("DROP TABLE IF EXISTS notes");
        onCreate(db);
    }

I had to modify the method like the following:

@Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                + newVersion + ", which will destroy all old data");
        db.execSQL("DROP TABLE IF EXISTS notes");
        db.execSQL("DROP TABLE IF EXISTS routes"); // line added
        onCreate(db);
    }

And I instead of:

private static final int DATABASE_VERSION = 2;

I changed it to:

private static final int DATABASE_VERSION = 3;

However, I'm not completely aware of the REAL affect the change to the database version had.

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