Develop Reference

How to fix empty string while fetching it from Database?

I am fetching a string from Database using the column id. When I enter a query in SQLite DB Browser it returns what is need but the same query returns nothing when coded through Java.
My Data Base contains a table named drugs which has 3 columns i.e. drug_id, drug_name and drug_overview. Using drug_id i am fetching drug_overview. I have tried the query in db browser which returns me the correct string from drug_overview but the same query returns nothing when coded through java.
SQLite DB Browser query:
SELECT * FROM drugs Where drug_id = 50;
JAVA CODE:
String query105 = "SELECT * FROM drugs Where drug_id = " + drug_id;
Log.e("TESTDB1","Drugs table query: " + query105);
Cursor c105 = db.rawQuery(query105,null);
if (c105 != null){
while (c105.moveToNext()){
String overview = c105.getString(c105.getColumnIndexOrThrow("drug_overview"));
Log.e("TESTDB1","Overview: " + overview);
}
c105.close();
}
Expected result is Overview: Acyclovir is an antiviral drug. It slows the growth and spread of the herpes virus in the body. It will not cure herpes, but it can lessen the symptoms of the infection.Acyclovir is used to treat infections caused by herpes viruses, such as genital herpes, cold sores, shingles, and chicken pox, as well as varicella (chickenpox), and cytomegalovirus.Acyclovir may also be used for purposes not listed in this medication guide.
But the actual result is Overview:
empty
. When i change the id in my query it gives the correct result from a different drug.

I am afraid that your problem may be with the actual data itself as Mike said in comment, I think your database in the files is old and you haven't copied the latest to folder. Try to re-install and delete old database

Your query returns 0 or 1 lines so I think you should use c105.moveToFirst() instead of c105.moveToNext(). moveToNext is supposed to be used for a list, not for a single entry. Do something like:
if (c105.moveToFirst()){
String overview = c105.getString(c105.getColumnIndex("drug_overview"));
// do something with the result
}
c105.close();

value of FeedEntry.COLUMN_NAME_UPDATED while creating a sql database

I am creating a sql database in my app and I am following the documentation on the official developer guide of android, at the webpage
http://developer.android.com/training/basics/data-storage/databases.html#ReadDbRow.
I don't understand what is the meaning of the FeedEntry.COLUMN_NAME_UPDATED value.
What should is value be? What does it mean actually?

It's the name of the update column in the feed table ;)
// How you want the results sorted in the resulting Cursor
String sortOrder = FeedEntry.COLUMN_NAME_UPDATED + " DESC";

Android: Where can I get the result from the SQLite command?

I am new for developing Android. May I ask where can I get the result of the sqlite command?
I would like to join 2 tables as follow: But How can I get the result in my application?
Quite confused about that and already search for several topics in google. Now, I can only get the result in the console by using adb shell. But it is meaningless.
SELECT Customers.FirstName, Customers.LastName, SUM(Sales.SaleAmount) AS SalesPerCustomer
FROM Customers JOIN Sales
ON Customers.CustomerID = Sales.CustomerID
GROUP BY Customers.FirstName, Customers.LastName

If you have the database object, you can just call
db.query() which will return a Cursor object, which contains the
query results.
here is a nice tutorial that could help you:
http://www.vogella.com/articles/AndroidSQLite/article.html

Sqlite support CREATE TABLE AS SELECT syntax. So try the following sql
private static final String TABLE_CREATE = "CREATE TABLE " + TABLE_NAME + " AS SELECT Customers.FirstName, Customers.LastName, SUM(Sales.SaleAmount) AS SalesPerCustomer
FROM Customers JOIN Sales
ON Customers.CustomerID = Sales.CustomerID
GROUP BY Customers.FirstName, Customers.LastName";
Execute it by:
SQLiteDatabase db;
//initialize db
db.execSQL(TABLE_CREATE);

SQL open a table confusion

I needed to store some data related to class periods in an Android project. After looking at my options, I thought a SQL database would be a good choice. Unfortunately, I can't seem to get my statement to actually open a database. My open database statement string goes like this:
"create table "+ DATABASE_PERIOD+" (_id integer primary key autoincrement,"
+KEY_CLASSTITLE+" text not null, "+KEY_PERIOD+" text not null,
"+KEY_XPERIODS+" text not null, "+KEY_DOUBLEPERIODS+" text not null);
I based it off of the Notepad project on the Android website. I just added a few more fields, but it is unable to open the database. If you guys want the error message or some other kind of info, I'll try to get it for you (This is my first time with SQL so I don't really know what is needed to fix this up). Thanks in advance!
The error message I'm getting goes like this:
android.database.sqlite.SQLiteException: no such table: periodData: , while
compiling: SELECT DISTINCT _id, title, period, xPeriods, doublePeriods FROM
periodData WHERE _id = -1
And as it says there, I'm using SQLite.
My code to put some data into the table in my Database Helper class:
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_CLASSTITLE, title);
initialValues.put(KEY_PERIOD, period);
initialValues.put(KEY_XPERIODS, xPeriods);
initialValues.put(KEY_DOUBLEPERIODS, doublePeriods);
return mDb.insert(DATABASE_PERIOD, null, initialValues);
I started using private static strings to ensure that my calls aren't incorrect (Thanks Barak for the catch!)

Your issue is the table name (as the error message indicates). From the code you show you created a table called "period". Yet you try to query it using the table name "periodData".
Two ways to fix it:
1) Change the table name in your database to periodData (more difficult as it involves re-creating the db).
2) Change the table name in your query from "periodData" to "period".

Check out the dev topic on http://developer.android.com/guide/topics/data/data-storage.html#db
You'll create a DbHelper class to help you open the database and your code will look something like:
SQLiteDatabase db = dbHelper.getReadableDatabase();
Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, sortOrder);
Hope this was helpful.

call sql from another class for android app

Hi
I have created a database for my application and i have added items to the database using methods from the database class. I am encountering a problem do when i try to execute a sql query in the other class(app.java), i need to reference a database and thats where im having the problem!
this is the sql query im trying to execute(in database.java)
public void getData(SQLiteDatabase db, String data){
String sql =
"SELECT permissions FROM genres WHERE name = "+data+";";
db.execSQL(sql);
}
and this is how i am calling it(in app.java)
appData.getData(db, chosenGenre);
I just dont no what to put for the "db" part in appData.getPermissions(db, chosenGenre);
Does anyone know how to do this?
Thanks

You would typically use a SQLiteOpenHelper to create the database files (if necessary) and obtain a SQLiteDatabase object which is used to access the actual database (files on disk read by SQLite).
http://developer.android.com/reference/android/database/sqlite/SQLiteOpenHelper.html
Here's a nice tutorial
http://www.anotherandroidblog.com/2010/08/04/android-database-tutorial/2/

You don't show the code where you define the database manager 'db'! If you are using a database created outside the android device, you might get some help from this link:
http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/
Also, I have found that it's best to frame all table names and supplied values in single quotes a la -
String sql = "SELECT permissions FROM 'genres' WHERE name = '" + data + "'";
Note that the semicolon is not required.