These are some common data modeling patterns.
Graffy’s caching algorithms work better if every value in the data has only one canonical path. Consider, for example, a provider that allows users to be retrieved by ID as well as by email address. Both these queries are supported:
{ user: { uid1: { name: true } } }
{ user: [{
$key: { email: 'bob@example' },
name: true
}] }
Result graphs must have the same keys as the query, so when the query uses a path that is not the canonical one, we provide it in $ref. The results for the query on the right would then be:
{ user: [{
$key: { email: 'bob@example' },
$ref: ['users', 'uid1'],
name: 'Bob Example'
}] }
Graffy doesn’t really support mutable arrays. Sure, we can use integers as keys, but there are no operations to insert or remove items while ensuring sequential array indices. Writing an array in Graffy will therefore replace the existing value completely, rather than adding or removing elements.
When specifying a query or graph, arrays are used commonly to represent nodes whose children have non-string keys (i.e. using the $key attribute). If the $key attribute is absent, or if the values in the array are not objects, we consider the integer index to be the key, and consider
There are different scenarios where we might use an array in JavaScript, and there are different ways to represent them in Graffy.
For example, an array of sentences in an article. We want to preserve order and allow storing duplicates. Paginated reads are possible, but partial updates are not.
This is the default treatment of arrays in graphs. They may be written like { prop: ['item1', 'item2'] } and read like { prop: [{ $first: 3 }] }.
These may hold any sort of JSON value, not just scalars.
For example, an array representing a game state in a board game like Battleship. These have the same properties as lists, but also require updates to values at specific indexes. We still can’t add or remove items.
These can be created using arrays and read using range keys just as with lists. To write to a specific index, use { prop: [{ $key: 2, $val: 'FF' }] }.
It is usually more convenient to give string names to each item in a small tuple. For example, if you’re storing coordinates of a point in a tuple, consider modelling it as an object with properties x and y instead.
TBD