Hi,
I'm prototyping a little graph library using SQLite. My idea is to store
vertices in a simple table like this:
CREATE TABLE "vertex" ("key" TEXT NOT NULL PRIMARY KEY, "metadata" JSON);
CREATE TABLE "edge" (
"id" INTEGER NOT NULL PRIMARY KEY,
"src" TEXT NOT NULL,
"dest" TEXT NOT NULL,
"metadata" JSON,
FOREIGN KEY ("src") REFERENCES "vertex" ("key"),
FOREIGN KEY ("dest") REFERENCES "vertex" ("key"));
What I'd like to do is allow querying of edges (or vertices) using a
*partial* metadata object. So if I had the following JSON object stored in
an edge's metadata:
{"k1": "v1", "k2": "v2", "k3": "v3"}
The user could provide me an object like {"k1": "v1", "k3": "v3"} and I
would be able to match the above edge's metadata.
I can see decomposing the user-provided dictionary and building up multiple
equality tests using the json_extract() function, e.g.:
select * from edge where json_extract(metadata, '$.k1') = 'v1' AND
json_extract(metadata, '$.k3') = 'v3';
But I was hoping there would be a more elegant way to express this that
someone would be able to share? It seems as though I should be able to use
`json_each()` (or even `json_tree()` if metadata could be nested?), but I'm
not sure how to formulate the query.
It'd be great if there were a JSON function like "json_contains()" where I
could write:
select * from edge where json_contains(metadata, '$', '{"k1": "v1", "k3":
"v3"}');
Any help appreciated!
Charlie
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