Develop Reference

How to iterate through all Contentresolver entries?

I have a database in my app, which I fill with data and an ID.
Then I request the database with the ID's I want:
Cursor cursor = contentResolver.query(uriPath, null, "ID = ?", new String[]{id1, id2, etc.}, null);
This retrieves me a cursor with all requested ID's .
How can I retrieve all objects in my UriPath ?

Just enter the Uri and leave the rest null
Cursor cursor = contentResolver.query(uriPath, null, null, null, null);

how to filter multiple data on multiple column sqlite database

i want to filter multiple data such as
id = "1,3,5" from columnid which is having 1 to 10 id
and another column such as name
name = "a,e,d" from name column of 10 records
and another criteria such as age
age = "21,23,20" from age column of 10 records from same table,
one example i got is
Cursor cursor = db.query("TABLE_NAME",new String[]{"ColumnName"}, "ColumnName=?",new String[]{"value"}, null, null, null);
which is just for one column but i want to get data from multiple column, can anyone help me?

try this working example,
Cursor cursor =
db.query(TABLE_DIARYENTRIES,
new String[] {},
STUDENT_ID + " IN ("+resultStudent+")"+ " AND " +CLASS_NAME + " IN ("+resultClass+")"
+ " AND " +SUBJECT_NAME + " IN ("+resultSubject+")"
null, null, null, null);
and your result string should be 'a','b','c'

I really like the way Google's example is structured. Because for noobies such as myself it makes it really clear what I am doing. And it is also more robust to SQL injections. Here is my modified version of the Google example:
//Column(s) I want returned
String[] projection = {"ColumnIWantReturned"};
//Column(s) I want to filer on
String selection = "FilterColumn1 IN (?) and FilterColumn2 IN (?, ?)";
String[] selectionArgs = {"ArgumentForFilterColumn1", "FirstArgumentForFilterColumn2", "SecondArgumentForFilterColumn2"};
Cursor cursor = db.query(
"MyTable", // The table to query
projection, // The array of columns to return (pass null to get all)
selection, // The columns for the WHERE clause
selectionArgs, // The values for the WHERE clause
null, // don't group the rows
null, // don't filter by row groups
null // The sort order
);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
Log.d("this-is-a-test", cursor.getString(0));
cursor.moveToNext();
}
cursor.close();

Changing order of listview results from SQlite

I have a listview in my application that displays records according to the primary key _ID field with the lowest _ID number first. How can I change that so it is the highest _ID number first in the listview? i.e reverse the order.
The db query currently generating the listview is below. Thanks!
public Cursor fetch() {
String[] columns = new String[] { DatabaseHelper._ID, DatabaseHelper.SLOC, DatabaseHelper.FLOC, DatabaseHelper.DSNM, DatabaseHelper.SDATE, DatabaseHelper.STIME };
Cursor cursor = database.query(DatabaseHelper.TABLE_NAME, columns, null, null, null, null, null);
if (cursor != null) {
cursor.moveToLast();
}
return cursor;
}

use this query:
Cursor c = mDb.query(DATABASE_TABLE, rank, null, null, null, null, yourColumn+" DESC");

You can use rawQuery method to hit any custom query like this and add ORDER BY ASC or DESC as you wish.
public Cursor fetch() {
String queryString = "SELECT * FROM tablename ORDER BY _id DESC"
Cursor cursor = sqLiteDatabase.rawQuery(queryString);
if (cursor != null) {
cursor.moveToLast();
}
return cursor;
}

SimpleAdapter needs an _id field

I got this :
Cursor c = db.query("Org", null, null, null, null, null, null);
which means I choose a table "Org", but together with this I need to make this :
Cursor c = db.rawQuery(" SELECT "+ id + " AS _id")
because SimpleAdapter need to have an _id field necessarily for some reason or it will crash with an error. How do I combine this 2 into one query?

The second parameter of the query function is the list of columns.
If you want to rename a column, you cannot just blindy return all columns but have to list the desired columns:
String[] columns = new String[] { id+" AS _id", "Name", "Color", "whatever..." };
Cursor c = db.query("Org", columns, null, null, null, null, null);

For your statement : Cursor c = db.query("Org", null, null, null, null, null, null); the second parameter is wrong, you shoukd mention the column names in it.
public Cursor query (boolean distinct, String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy, String limit)
Whereas for,
Cursor c = db.rawQuery(" SELECT "+ id + " AS _id from Org");
means that you Select id and create an alias of it using AS into _id, and you are selecting this id from Org table.
so now you will be able to access the result from this query from the column name _id, and in order to access the result use:
c.moveToFirst();
while (c.moveToNext())
{
System.out.println(c.getString(c.getColumnIndex("_id"));
}

sqlite rand() unique _id return sqlite

How can i get a predifined(users choise) number of rows from my database and ensure that i display them only once? If use rand() limit 1, and return the cursor the same _id may return twice or more.
I use this
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query("THESIS Order BY RANDOM() LIMIT 1",new String[] { "*" }, null, null, null, null, null);
cursor.moveToFirst();
return cursor;

SELECT DISTINCT column_name(s) FROM table_name
distinct world will return unique output it will not give you repeated data