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Get records that don't have their ID in a seperate String Set - DynamoDB

I'm using Amazon Dynamo DB to down load a number of records to Android.
I have 2 Tables.
Table 1 contains a Set of Strings containing ID's
Table 2 has records each with an individual ID.
I want to download 10 records from Table 2 only if the record ID does not appear in the Set of strings in Table 1.
I can do this by downloading all the records in table 2 and then not saving /displaying the ones that appear in the String Set in table 1. However is there a way to only download the ones that don't appear in the String Set?
Any ideals would be appreciated.
Many Thanks

In order to query a dynamodb you need the attribute to either be a range key or partition key which in terns need to be scalar so you cannot directly query what you want. Your best chance of doing what you want if I understand your requirement is scan operation. Scan the whole table(2) and then use queryExpression to filter the results you get using a nested query in table one. This demands you to make the "Set of Strings" either either partition or range key in your first table.

Read from a Single Table and write it to different database tables using spring batch

I am kind of new to spring batch processing. I want to have the following functionality-
Read from a single table of Mysql Database.
Call the item processor which will parse the data into 5 different objects.
Call Item writer to write these 5 objects to 5 different tables ( condition is the id returned after the first insert from first object is used for the second object in the table data).
How can I achieve this using Spring batch, is there any alternate approach which I can use to increase the performance and get the functionality?
Any Help will be appreciated.
Thanks!!

Linking an editable tableView to a database in javaFX

I'm working on a project for JavaFX and databasing practice (mostly I'm a beginner), where I have a unique class which holds records about concerts (name, location, date etc). I originally held these in an observable arraylist which populated a table view. From here the records could be editted, deleted or new ones added.
I am now storing these in a database using ORMLite and sqlite. This is so I can perform filtering on the data (ie show all events in a particular location) and then show this on the table.
My issue is that when I read in the data from the database I convert it to a ObservableArrayList so the table view can use it, but by creating the new array list my edit/new/delete buttons only effect this list and not the database. The problem is that every time I perform a query such as adding or deleting records to the database, it needs to re-produce the observableArrayList for the tableView which is taking around 5 seconds with ~250k records.
Is there a more efficient way to work with databases and javaFx tableViews?

Is there a more efficient way to work with databases and javaFx tableViews?
How about setting some sort of dirty flag on the records when you update certain fields and then go through your list of records and only make the DAO calls on those that are dirty? Maybe an enum with CREATE, DELETE, UPDATE, NONE.
Another idea would be to do your dao.update(...), dao.delete(...), or dao.create(...) calls whenever you update an record although you may want to do the chances all once time.
Last idea is to keep 4 arrays. One with the entire list, one for the new records, one for the dirty records, and one for the records to be deleted. You would add the records to the lists as edit/new/delete buttons are pressed and then at the end you can save them all at once.

Loading a Single column out of 50 Using Load() of Hibernate

Suppose there are 50 columns in database table. Each column contains image(binary data). You need to display only one one image out of 50 at a time. How would you achieve the same via hibernate? Keep in mind that executing load on the table will result in loading complete row while we need only one column data.

Pavnesh, I am answering the question in a geenral fashion. If you just one one column from the table create a named query and return that single column, and retrieve the data in your DAO class with proper datatype.
and if you want just a single row use query.setMaxresult function and give the value as 1 and then you can select the particular column value from the row,but however in this case only the top row it will return.

Fetching records one by one from PostgreSql DB

There's a DB that contains approximately 300-400 records. I can make a simple query for fetching 30 records like:
SELECT * FROM table
WHERE isValidated = false
LIMIT 30
Some more words about content of DB table. There's a column named isValidated, that can (as you correctly guessed) take one of two values: true or false. After a query some of the records should be made validated (isValidated=true). It is approximately 5-6 records from each bunch of 30 records. Correspondingly after each query, I will fetch the records (isValidated=false) from previous query. In fact, I'll never get to the end of the table with such approach.
The validation process is made with Java + Hibernate. I'm new to Hibernate, so I use Criterion for making this simple query.
Is there any best practices for such task? The variant with adding a flag-field (that marks records which were fetched already) is inappropriate (over-engineering for this DB).
Maybe there's an opportunity to create some virtual table where records that were already processed will be stored or something like this. BTW, after all the records are processed, it is planned to start processing them again (it is possible, that some of them need to be validated).
Thank you for your help in advance.

I can imagine several solutions:
store everything in memory. You only have 400 records, and it could be a perfectly fine solution given this small number
use an order by clause (which you should do anyway) on a unique column (the PK, for example), store the ID of the last loaded record, and make sure the next query uses where ID > :lastId