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();

How to Close SQLite Cursor and other open SQLite database?

I am trying to write a code in Android and going through following errors. I am opening a SQLite database and using Cursor.
Java Code
for(int y3=0;y3<10;y3++)
{
String sql_query5= "SELECT * FROM Data WHERE Id="+y3+"";
Cursor cur5 = SQLiteDatabase.openDatabase(db, null, SQLiteDatabase.OPEN_READWRITE).rawQuery(sql_query5, null);
if(cur5.moveToNext())
{
//
}}
So i need to display the Age in the layout but i am facing SQLiteCantOpenDatabaseException and Database object not closed. I don't understand the errors.
Please let me know some solution and suggestion !!!

Do not use hard-coded file paths. You have no guarantees about the structure of the filesystem.
Learn to use SQLiteOpenHelper. This is what helps you create and maintain your SQLite database. Instead of trying to open the database yourself, you create a new SQLiteOpenHelper and call getReadableDatabase().
When you are done reading from a Cursor, call cursor.close().
If you want to close the database, you can call close() on it as well; just be aware that any cursors you got by querying it will no longer be able to give you data, so make sure you are finished them those before closing the database.

add '' in your
String sql_query5= "SELECT * FROM Data WHERE Id='"+y3+"' ";

How to check if a table exists in Android?

I'm trying to query on a table dormpolicy
String operatorName = "46001";
String selection = "(plmn = '"+operatorName+"')";
URI CONTENT_URI_DORMPOLICY = Uri.parse("content://nwkinfo/nwkinfo/dormpolicy");
cursor = phone.getContext.getContentResolver().query(CONTENT_URI_DORMPOLICY, null, selection, null, null);
I get error log:
SQLiteQuery: exception: no such table: dormpolicy;
query: SELECT * FROM dormpolicy WHERE ((plmn = '46001'))
This issue happen not always in my phone.
It seems that sometimes,when I access the table before the table was created.
Is there any way that before I query the table, I check if the table exist?
And how?

My answer is twofold:
To strictly answer the question, I will redirect you to How does one check if a table exists in an Android SQLite database?
But rather than manually checking for tables' existence, I suggest you use the SQLiteOpenHelper class. This will help you manage your tables in a structured way. That includes handling database upgrades. Have a look at this for a quick start: http://developer.android.com/guide/topics/data/data-storage.html#db

How can load some value in the sqlite-database

I have a database now i have to check whether it is empty or not. if empty i have to write the code for insert values otherwise i have to update the values of the fields.
please help me..

You can try something like this:
// Open or crare
myDB = this.openOrCreateDatabase("MyDatabaseName", MODE_PRIVATE, null);
//Check if exists (if not create the table)
myDB.execSQL("CREATE TABLE IF NOT EXISTS MyTableName (Name1 VARCHAR, Name2 VARCHAR);");
//Insert or update your lines
myDB.execSQL("INSERT INTO MyTableName (Name1 , Name2 ) VALUES ('XXX', 'YYY');");

Have you done the Google Notepad tutorials 1,2,3? they have a bunch of database help
Hope that can help

It's possible to include a .db file in your application package and use that as the starting point for your device-side database. It goes in the assets folder. You'll have to manually copy the values out of that .db into the one on the device in your startup method, but it saves putting a bunch of SQL INSERT calls in code.
The MOTODEV Studio Database perspective will assist you with this. You can use it to create a .db from scratch and populate it with your default values. Then, there is a wizard that will set up a content provider and accessor classes for the fields if you need them.
Disclaimer: I'm the product manager for MOTODEV Studio.

How to access an existing sqlite database in Android?

So far we have developed apps in android that create database on runtime. We like to know how can we access a pre-built or existing database/sqlite file in our android app? Please provide detail

Take a look at the documentation for android.database.sqlite.SQLiteDatabase.
In particular, there's an openDatabase() command that will access a database given a file path.
SQLiteDatabase db = SQLiteDatabase.openDatabase(path, null, 0);
Just specify the path to your database as the path variable, and it should work.

I have followed the same road and found two issues:
Include the _id field on any table you create and make sure it is
part of the columns to return when you query any table.
You may run into an error like Failed to open the database. closing
it.. This is because we are copying the database from an existing
file instead of creating tables on top of a db created by the sqlite
android API and the table android_metadata may not exist. For
creating it just run the following query on your db:
CREATE TABLE android_metadata (locale TEXT);
And add the corresponding locale, for example en_US

First copy your SDCARD and give it's path in the variable "DBNAME" in the following example.
it will be something like "/sdcard/persons.db" if you are directly pulling it to sdcard.

Use this for accessing database in application :
Context context = getApplicationContext();
context.getDatabasePath(DataBaseHelper.database_Name);