How to fix empty string while fetching it from Database?

Question

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.

"drug_overview" looks rather like a column name than it does a column_index — Stultuske
– Stultuske, Commented Mar 28, 2019 at 13:02
c105.getColumnIndex("drug_overview") returns the column index — Huzaifa Asif
– Huzaifa Asif, Commented Mar 28, 2019 at 13:04
did you check that your database on the device is correctly filled by removing the WHERE part? — Christian
– Christian, Commented Mar 28, 2019 at 13:06
Yes my database is not empty as i can fetch the name of the drug by the same query — Huzaifa Asif
– Huzaifa Asif, Commented Mar 28, 2019 at 13:08
You are missing this line SQLiteDatabase db = this.getReadableDatabase(); — primo
– primo, Commented Mar 28, 2019 at 13:11

Usman Iqbal · Accepted Answer · 2019-03-29 13:35:53Z

0

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

edited Mar 29, 2019 at 13:35

answered Mar 29, 2019 at 13:33

Usman Iqbal

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2 Comments

Huzaifa Asif Over a year ago

Thank You Sir! I had to uninstall my app and then reinstall it with new database that's all!

Usman Iqbal Over a year ago

That's great. Happy to know that your problem is resolved.

Nicola Gallazzi · Accepted Answer · 2019-03-28 13:27:07Z

0

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();

answered Mar 28, 2019 at 13:27

Nicola Gallazzi

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14 Comments

Huzaifa Asif Over a year ago

Well i have multiple entries in it and i am fetching a list of drugs from it. So i had to use next. c105.moveToNext()

Nicola Gallazzi Over a year ago

Multiple entries with the same drug_id?

Nicola Gallazzi Over a year ago

Are you checking if c105.moveToNext() is true?

Nicola Gallazzi Over a year ago

You can also try to use getColumnIndexOrThrow to see if your column name is mispelled

Huzaifa Asif Over a year ago

No multiple entries with different drug id's

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