How can i check to see if my sqlite table has data in it?

Question

EDIT, Changed the code slightly based on answers below, but still haven\'t got it working. I also added a log message to tell me if getCount was returning > 0, and i

Answer 1

My app was crashing trying the above codes, so I did this and now it's working perfectly!

public boolean checkIfEmpty()
{
    Cursor cursor = getDatabase().query(DatabaseHelper.Products.TABLE,
            DatabaseHelper.Products.COLUMNS, null, null, null, null, null);

    if (cursor != null)
    {
        try
        {
            //if it is empty, returns true.
            cursor.moveToFirst();
            if (cursor.getInt(0) == 0)
                return true;
            else
                return false;
        }

        //this error usually occurs when it is empty. So i return true as well. :)
        catch(CursorIndexOutOfBoundsException e)
        {
            return true;
        }

    }
    return false;
}

Answer 2

You can check it manually :

1. Go to DDMS in File Explorer. /data/data/(your application package)/databases Here you'll get your database file. And if you want to see inserted values in table.

2. Copy adb, aapt, AdbWinApi.dll and AdbWinUsbApi.dll files from platform_tools to tools folder.

3. Then Open Command Prompt and set your path to "Tools" directory where your android setup exist. It look like as :- (Local Drive):\Android\android-sdk-windows\tools

4. After set path you'll write command "adb shell" without quotes. E:\Developers\Android\android-sdk-windows\tools> adb shell

5. Press Enter and write path of DDMS told above:- # sqlite3 /data/data/(Your Application Package)/databases/name of database

6. Press Enter sqlite>.tables

7. Press Enter And you'll get all table's name existing in that database.

sqlite> Select * from table name

All data exists in that table will show.

For any further query feel free to comment.

Answer 3

Another alternative to the one already mentioned would be to use the function queryNumEntries from de class DatabaseUtils.

An example may be as follows:

public boolean checkEmpty(SQLiteDatabase db, String table){
        return DatabaseUtils.queryNumEntries(db, table) == 0;
}

Answer 4

The query SELECT COUNT(*) on an existing table should never return null. If there are no rows in the table, it should return one row containing the value zero.

Conversely, a row with a non-zero value indicates that it's not empty.

In both cases, one row should be returned, meaning that it will always go through the

//do nothing everything's as it should be

section.

To fix it, leave your query as-is (you don't want to do select column_name simply because that would be unnecessary and possibly a little inefficient). Leave it as select count(*), which will always return one row, and use the following code (tested only in my head so be careful):

Cursor cur = db.rawQuery("SELECT COUNT(*) FROM CAT_BUD_TAB", null);
if (cur != null) {
    cur.moveToFirst();                       // Always one row returned.
    if (cur.getInt (0) == 0) {               // Zero count means empty table.
        for (int i = 0; i < 13; i++) {
            db.execSQL (catInsertArray[i]);
        }
    }
}

Answer 5

The rawQuery returns a Cursor object which is positioned before the first entry (See more info here) SELECT COUNT(*) will always return a result (considering the table exists)

So I would do:

if (cur != null){
    cur.moveToFirst();
    if (cur.getInt(0) == 0) {
      // Empty 
    }

}

Answer 6

My way of checking was something like this:

Cursor cursor = db.query(DbHelper.DB_NAME,DbHelper.DB_C_ID_ONLY,null,null,null,null,null);
if(cursor.isAfterLast())

I get the _id entries which in my case are auto-increment. If the DB is empty, isAfterLast for sure returns true.