Develop Reference

CursorIndexOutOfBounds Exception: Index 0 requested, with a size of 0

I tried to read the SQLite database column and store each values in an String array. I did the following but it returned exception cursoroutofbounds. Help me figure out what I'm doing wrong?
public String[] getPlaces(){
SQLiteDatabase db = this.getReadableDatabase();
String [] columns = {"place1"};
c = db.query("rates_table", columns, null, null, null, null, null);
String[] places = new String[c.getColumnCount()];
c.moveToNext();
for(int i=0; i<c.getColumnCount(); i++)
places[i] = c.getString(i);
return places;
}

Here :
String[] places = new String[c.getColumnCount()];
c.getColumnCount() will return count of column in row instead of number of rows in column. use c.getCount() to initialize places Array:
String[] places = new String[c.getCount()];
Or use ArrayList .

I worked out for sometime and found out the solution:
public String[] getPlaces(){
SQLiteDatabase db = this.getReadableDatabase();
String [] columns = {"place1"};
c = db.query("rates_table", columns, null, null, null, null, null);
c.moveToFirst();
ArrayList<String> places = new ArrayList<String>();
while(!c.isAfterLast()) {
places.add(c.getString(c.getColumnIndex("place1")));
c.moveToNext();
}
c.close();
return places.toArray(new String[places.size()]);
}

You need to change your query and further processing at multiple places. Rectify your third parameter of query method to a proper where clause or keep it null. Loop through the cursor properly and add it to your String.
public String[] getPlaces(){
SQLiteDatabase db = this.getReadableDatabase();
String [] columns = {"place1"};
c = db.query("rates_table", columns, null, null, null, null, null);
if (c.getCount() > 0) {
String[] places = new String[c.getCount()];
int i=0;
c.moveToFirst();
do {
places[i] = c.getString(c.getColumnIndex(0)));
} while (c.moveToNext());
return places;
}
c.close();
db.close();
}

First you have an issue with c = db.query("rates_table", columns, "place1", null, null, null, null);
The third parameter will result in no rows being selected.
You could use c = db.query("rates_table", columns, null, null, null, null, null); , which would return all rows.
Or you could use c = db.query("rates_table", columns, "place1 = 'myplace'", null, null, null, null);, in which case only rows that have the value myplace in the column place1 would be shown.
The best practice way is to use the 3rd and 4th parameter in conjunction where you use ? placeholders in the 3rd parm (e.g "place1=?") and corresponding args in the 4th parameter (e.g. new String[]{"myplace"}), so to replicate the previous query you could have c = db.query("rates_table", columns, "place1=?", new String[]{"myplace}, null, null, null);
Using c.moveToNext, will try to move to the next (initially the first) row of the cursor. However, if it cannot move (i.e. there are no rows, as would be the case as described above) it will not fail, rather it returns false (true if the cursor could be moved).
So You need to check this otherwise, in the case of no rows, an attempt to access a row will fail with Cursor out of bounds Index 0 requested, with a size of 0 (i.e. you requested the first (index 0) when the size of the cursors (number of rows) is 0.
There are various ways to check.
However I suspect you will then wonder why your loop only displays 1 column. That would be because you have said in the query to just get 1 column.
If you changed the query's 2nd parameter to null, it would get all columns.
At a guess you want to return an array of all places.
Assuming this then :-
// get Cursor with all rows(3rd parm null) for the place1 column (2nd parm)
c = db.query("rates_table", columns, null, null, null, null, null);
// Create String array according to the number of rows returned.
String[] places = new String[c.getCount()];
// loop through all rows setting the respective places element with the
// value obtained from the Cursor
while (c.moveToNext) {
places[c.getPosition()] = csr.getString(csr.getColumnIndex("place1"));
}
csr.close(); // Should always close a Cursor
return places;

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();

Skip deleted/empty rows sqlite

I am populating AChartEngine from sqlite database and I need all of the data to be displayed. The problem I'm having is when I delete a record the graph series stops populating at the deleted record. I need to find a way to skip over deleted/empty records and continue populating my graph. I need it to do it the same way listview skips over deleted records and keeps on displaying all rows. I am very new to a lot of this and am having a very difficult time with this. I have tried to write if statements in order to skip deleted/empty rows but nothing seems to work. Thank you for helping!
in my graphing activity:
for (int i = 1; !c.isAfterLast(); i++) {
String value1 = db.getValue1(i);
String value2 = db.getValue2(i);
c.moveToNext();
double x7 = Double.parseDouble(value1);
double y7 = Double.parseDouble(value2);
myseries.add(x7, y7);
}
I am getting error: CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
If I surround with try and catch it will populate rows up until the deleted record.
"EDIT"
in my sqlite database:
public String getValue1(long l) {
String[] columns = new String[]{ EMP_DEPT };
Cursor c = db.query(EMP_TABLE, columns, EMP_ID + "=" + l, null, null, null, null);
if (c != null){
c.moveToFirst();
String value1 = c.getString(0);
return value1;
}
return null;
}
public String getValue2(long l) {
String[] columns = new String[]{ EMP_DATE1 };
Cursor c = db.query(EMP_TABLE, columns, EMP_ID + "=" + l, null, null, null, null);
if (c != null){
c.moveToFirst();
String value2 = c.getString(0);
return value2;
}
return null;
}

Your issue is that your safety net for commands on rows that don't exist is to use if (c != null){ and then perform your commands inside that block, but a Cursor request from a query will never come up null, it will instead result in a cursor object with no rows.
A more appropriate solution to use this as your safety net instead if (c.moveToFirst()){ Because the method itself returns a boolean for if the method actually carried itself out in the first place - true if it moved and false if not (which occurs when there's no rows to move into). another check, if you wish, would be to see how many rows the cursor has with c.getCount().
Additionally, you should combine your methods so that you don't make redundant queries to the database:
public String[] getValues(long l) {
String[] results = new String[2];
String[] columns = new String[]{ EMP_DEPT, EMP_DATE1 };
Cursor c = db.query(EMP_TABLE, columns, EMP_ID + "=" + l, null, null, null, null);
if (c.moveToFirst()) {
results[0] = c.getString(0);
results[1] = c.getString(1);
} else {
Log.d("GET_VALUES", "No results formed from this query!");
}
return results;
}

You should use a single query to get all values at once:
SELECT Date1 FROM MyTable WHERE id BETWEEN 1 AND 12345
or:
db.query(EMP_TABLE, columns, EMP_ID + " BETWEEN 1 AND " + ..., ...);
Then missing values will just not show up when you iterate over the cursor.

How to query a single item based on its name in a sql database and return cursor?

I have a database with all food items. I want to search the database for a variable food item and get its Cursor. Let us take food item = Oranges as an example. The following line gives the correct result when typed in terminal.
SELECT * from food WHERE item = 'Oranges'
To implement it I made a method called getOneItem in the class which extends SQLiteOpenHelper as below.
public Cursor getOneItem(String itemName) {
return myDataBase.query(TABLE, null, C_NAME+" = " +itemName , null, null, null, null);
}
But when the method is called I get the error "No such column: Oranges, while compiling
SELECT * from table WHERE item = Oranges
Why is the computer searching for a column called Oranges and not searching inside the column for Oranges?
When I modified the method to:
public Cursor getOneItem(String itemName) {
return myDataBase.query(TABLE, null, C_NAME+" = '" +itemName +"'", null, null, null, null);
}
I get CursorIndexOutOfBoundException, Index -1 requested with size of 1

Second argument should not be null... Specify the columns that u need to display..
return myDataBase.query( TABLE, new String[] {
C_NAME
},
C_NAME + "= ?" ,
new String[] { itemName }, ,
null,
null,
null);

How to pass multiple values to query dynamically in android?

In my project I have to select multiple values and pass it to a query. i.e page1 contains checkboxes. I am storing the selected checkbox id's into an array.
I am shuffling that array and getting the values randomly. Now I need to pass these random values to a query. Using IN operator in database I can pass the values
statically but how can I pass the values dynamcially to the query.
For ex:(Passing values statically)
SELECT * FROM Persons WHERE person_id IN ('21','22')
In the above query the id's 21 and 22 are know previously and so we are passing statically but I want to send the values to query dynamically.
Page1:
public static ArrayList<String> chksublist = new ArrayList<String>();
Page2:
Collections.shuffle(chksublist );
SELECT * FROM Persons WHERE person_id IN ('21','22')
In the above line I want to send the random values which are in chksublist array.

String query = "SELECT * FROM Persons WHERE person_id IN (" + TextUtils.join(",", chksublist) + ")";
But shuffling the chksublist before sending it to your SQL query has no impact on the result set you get from SQL. It will not randomly permute your results. Remove Collections.shuffle(chksublist); and use
String query = "SELECT * FROM Persons WHERE person_id IN (" + TextUtils.join(",", chksublist) + ") ORDER BY RANDOM()";

see how values are dynamicaly passed
// Getting single contact
public Contact getContact(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
KEY_NAME, KEY_PH_NO }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
// here new String[] { String.valueOf(id) } value is added dynamicaly which is passed to the function
if (cursor != null)
cursor.moveToFirst();
Contact contact = new Contact(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2));
// return contact
return contact;
}

You can generate your query like this
int values[]; //it contains your generated values like 21,22....
String query="SELECT * FROM Persons WHERE person_id IN (";
for(int i=0;i<values.length;i++){
query=query+"'"+values[i]+"'";
if(i<values.length-1){
query=query+","; //No , after last values
}
}
query+=")";
finally pass this query.

Try it
cursor = database.query(tablename,
new String[] {"TopName"}, "id IN(?,?)", new String[]{"2","3"}, null, null, null);
using raw query
String query = "SELECT * FROM Persons WHERE person_id IN ("+parameter1+","+parameter2+")";
db.rawQuery(query);