How to check if a row exists in a table?

Question

I'm using this code to check if a row exists in my table:

public boolean checkIdiomInFavorite(Idiom idiom){
        String query = "SELECT *" +  " from " + IdiomsOpenHelper.TABLE_FAVORITE +
                " where " + IdiomsOpenHelper.COLUMN_FAV_ID + " = ?;";
        Cursor cursor = database.rawQuery(query,new String[] { String.valueOf(idiom.getId()) });
        if(cursor.moveToNext()){
            return true;
        }
        else{ 
            return false;
        }
    }

But always I get false.
Any idea?

Phantômaxx · Accepted Answer · 2014-09-28 12:12:47Z

1

I'd replace this

if(cursor.moveToNext()){
        return true;
    }
    else{ 
        return false;
    }

with

return(cursor.moveToFirst());

edited Sep 28, 2014 at 12:12

answered Sep 28, 2014 at 11:05

Phantômaxx

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12 Comments

Phantômaxx Over a year ago

Does the record exist in the specified table, with that condition matched?

Sirwan Afifi Over a year ago

Yes, I've tested in database, it returns the record.

Phantômaxx Over a year ago

What does idiom.getId() return?

Phantômaxx Over a year ago

So, does this query

String query = "SELECT * FROM " + IdiomsOpenHelper.TABLE_FAVORITE +                 " WHERE " + IdiomsOpenHelper.COLUMN_FAV_ID + " = 5";

work?

Sirwan Afifi Over a year ago

Yes it does, I test this query, it returns the record: codeSELECT * FROM Favorite WHERE _id = 5code

|

Squonk · Accepted Answer · 2014-09-28 12:45:00Z

Change this query string...

String query = "SELECT *" +  " from " + IdiomsOpenHelper.TABLE_FAVORITE +
            " where " + IdiomsOpenHelper.COLUMN_FAV_ID + " = ?;";

...to...

String query = "SELECT * from " + IdiomsOpenHelper.TABLE_FAVORITE +
            " where " + IdiomsOpenHelper.COLUMN_FAV_ID = " + idiom.getId();

Then change this line...

Cursor cursor = database.rawQuery(query,new String[] { String.valueOf(idiom.getId()) });

...to...

Cursor cursor = database.rawQuery(query, null);

Mehdi · Accepted Answer · 2014-09-28 11:05:36Z

use the code below:

public boolean checkIdiomInFavorite(Idiom idiom){
        String query = "SELECT *" +  " from " + IdiomsOpenHelper.TABLE_FAVORITE +
                " where " + IdiomsOpenHelper.COLUMN_FAV_ID + " = ?;";
        Cursor cursor = database.rawQuery(query,new String[] { String.valueOf(idiom.getId()) });
        if(cursor.moveToNext()){
            return true;
        }
        else{ 
            return false;
        }
    }

can u able to detect the deference? I am using SELECT *, what means all the columns ... or use any column name you actually have in that table.

You also can count the total rows of the table to check if it returns 0... if returns 0 then no data exists.

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