How to maintain relationships when importing data into Parse.com - mysql

Question

I have a database that I'd like to import into Parse.com but having trouble wrapping my head around how the data should be stored in Parse and maintain relationship between this data.
Here's my current data and their relationship.
Table 1: Videos
-> VideoName
-> URL
Table 2: Performers
-> PerformerName
-> Bio
Table 3: Games
-> GameName
-> GameDetail
Table 4: Seasons
-> SeasonName
-> SeasonDetail
The relationships are:
-> Each Season can have more than one video, but each video can only be associated with one season.
-> Each video can have one or more Game
-> Each Video can have one or more Performer
-> Each Game can be associated with one or more Video
-> Each Game can be associated with one or more Performer
-> Each Performer can be in one or more Videos
-> Each Performer can be associated with one or more Game.
This means that there's many to many relationships between the data.
If someone can help me get my thinking straight on how Parse does relational databases/information I'd appreciate it. I have already read the Relational Data documentation but I'm not fully understanding how it applies to my data.
I would like to be able to export the data out of my database and import it into Parse. I am open to any suggestion on getting this data into Parse and maintaining relationships.
I need the relationships because the app is going to be pulling queries like:
-> Retrieve all videos where performer = x
-> Retrieve all games where performer = x
-> Retrieve all performers where game = x
-> Retrieve all videos where season = x
plus others as needed.
I hope someone can help. If you can provide specific examples based on the information I have above that would be excellent! :-)

Answer 1

Parse supports relationships in a number of ways:
Pointer (think foreign key ID)
Array of Pointers (think join table, but only when you always want to get all of them)
Relation (think join table, where you want to query for a sub-set)
What you use depends greatly on your queries. In your case I would suggest the following:
Videos:
Name (string)
URL (string)
Season (pointer)
Games (array, assuming this is a short list)
Performers (array)
Performers:
Name (string)
Bio (string, possibly with HTML or other markup)
Games:
Name (string)
Detail (string)
Performers (array)
Seasons:
Name (string)
Detail (string)
For your queries (in JavaScript since you didn't specify a language):
// setup bits
var Video = Parse.Object.extend("Video");
var Performer = Parse.Object.extend("Performer");
var Game = Parse.Object.extend("Game");
var Season = Parse.Object.extend("Season");
// All videos where performer = x
var videosForPerformerQuery = new Parse.Query(Video);
// assumes performerX has been retrieved or initialised with an ID
// equalTo in this case will find records where performerX is in the array of performers
videosForPerformerQuery.equalTo('performers', performerX);
// if you need to output the full list of performers:
videosForPerformerQuery.include('performers');
// if you need the full season object:
videosForPerformerQuery.include('season');
videosForPerformerQuery.find({
success: function(results) {
// TODO: handle array of video objects in results
},
error: function(error) {
// TODO: handle error
}
});
// All games where performer = x
var gamesForPerformerQuery = new Parse.Query(Game);
// .. identical to above ..
// All performers where game = x
var gameQuery = new Parse.Query(Game);
gameQuery.include('performers');
// gameObjectID is a string key, e.g. "xWMyZ4YEGZ"
gameQuery.get(gameObjectId, {
success: function(game) {
// TODO: game.performers array should be populated, use it
},
// .. error handler too ..
});
// All videos where season = x
var videosForSeason = new Parse.Query(Video);
videosForSeason.equalTo('season', seasonX);
// .. find same as above examples ..
Sometimes you'll want bi-directional joins. You can either manually populate an Array/Relation on each end, or use a new object to hold the relations (especially if the relation contains extra info). Example:
GamePerformers:
Game (pointer)
Performer (pointer)
Role (string)
Query it and include the Game/Performer as needed:
var GamePerformers = Parse.Object.extend("GamePerformers");
var performersForGameQuery = new Parse.Query(GamePerformers);
performersForGameQuery.equalTo('game', gameX);
performersForGameQuery.include('performer');
performersForGameQuery.find({
success: function(results) {
for (var i = 0; i < results.length; i++) {
var object = results[i];
console.log('Performer: '
+ object.get('performer').get('name')
+ ' played role: '
+ object.get('role'));
}
}
});