Question

I am new to Android programming and am trying to understand the best practices.

I want to do multiple inserts into two different database tables, but as one transaction (as the tables shared a foreign key). I want my function to return a result so that I can display a Toast or something to say that an error occurred, otherwise I want to return the row ID of the first insert.

I believe one way of doing this is sort-of as follows (Disclaimer: psuedo-ish code, probably won’t compile!):

Long result = -1;
myDatabase.beginTransaction();
try {
   // Insert into first table
   ContentValue someValues = new ContentValues();
   someValues.put("dbfield1", 1);
   result = myDatabase.insert(DATABASE_TABLE_1, null, someValues);

   if (-1 != result ) {         
       // Insert into second table
       someValues.clear();
       someValues.put("dbfield2", 2);

       if( myDatabase.insert(DATABASE_TABLE_2, null, someValues) < 0 ) {
           result = -1;
       }
   }

   mDatabase.setTransactionSuccessful();
} catch(Exception e) {
    // An error occurred
    result = -1;
} finally {
   mDatabase.endTransaction();
}

Is there a simpler/better way of doing this?

Answer 1

You can override bulkInsert inside your ContentProvider
your Code looks fine. The Method should return the inserted Rows Value but you can customize that so you return only the first ID.

public int bulkInsert(Uri uri, ContentValues[] values) {
    Log.e("BULK", "Bulk insert started for URI" + uri.toString());
    bulkSqlDB = database.getWritableDatabase();
    int numInserted;

    bulkSqlDB.beginTransaction();
    try {
        for (ContentValues cv : values) {
            insert(uri, cv);
        }
        bulkSqlDB.setTransactionSuccessful();
        numInserted = values.length;
    } finally {
        getContext().getContentResolver().notifyChange(uri, null);
        bulkSqlDB.endTransaction();
    }
    return numInserted;
}