How to Implement Cassandra Counter Columns with phantom-dsl? - scala

Question

This is an extension to this question:
How to increment Cassandra Counter Column with phantom-dsl?
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In Thiagos example the two tables; 'songs' & 'songs_by_artist' both have the same rows but with different partitions (primary keys / clustering columns)
CREATE TABLE test.songs (
song_id timeuuid PRIMARY KEY,
album text,
artist text,
title text
);
CREATE TABLE test.songs_by_artist (
artist text,
song_id timeuuid,
album text,
title text,
PRIMARY KEY (artist, song_id)
) WITH CLUSTERING ORDER BY (song_id ASC);
This means inserting, updating and deleting across both tables within the SongsService works with the same base data / rows.
How would you for example have a table such as 'artist_songs_counts', with columns 'song_id' (K) and 'num_songs' (++) and ensure that 'SongsService' adds corresponding row to each table; 'songs' & 'songs_by_artist' & 'artist_songs_counts' (where there are different numbers of row but information should be linked, such as the artist info).
CREATE TABLE test.artist_songs_counts (
artist text PRIMARY KEY,
num_songs counter);

Answer 1

SongsService extends ProductionDatabaseProvider that gives to you an object called database where you have access to tables under a certain database:
/**
* Find songs by Id
* #param id
* #return
*/
def getSongById(id: UUID): Future[Option[Song]] = {
database.songsModel.getBySongId(id)
}
Or even better, handling two tables at the same time:
/**
* Save a song in both tables
*
* #param songs
* #return
*/
def saveOrUpdate(songs: Song): Future[ResultSet] = {
for {
byId <- database.songsModel.store(songs)
byArtist <- database.songsByArtistsModel.store(songs)
} yield byArtist
}
Since through a database object you can access all tables that belongs to a specific Database, I would implement a counter for artist the following way:
def increment(artist: String): Future[ResultSet] = {
update
.where(_.artist eqs artist)
.modify(_.numSongs += 1)
.future()
}
Then the saveOrUpdate method could be written as below:
def saveOrUpdate(song: Song): Future[ResultSet] = {
for {
byId <- database.songsModel.store(songs)
byArtist <- database.songsByArtistsModel.store(songs)
counter <- database.artistSongsCounter.increment(song.artist)
} yield byArtist
}