How to join tables with a array of IDs

javascript, rethinkdb

Solution

You're using concatMap incorrectly, here's what you want the first part of your query to be.

r.table("stores")
 .concatMap(function (x) {
   return x("locations");
 })

Try running that, it should give you:

["5fa96762-...", "80362c86-...", ...]

Now we need to join this to the other table. To join an array of ids to a table you can use eqjoin like so:

array.eqJoin(function (row) { return row; }, table)

There's more details here: rql get multple documents from list of keys rethinkdb in javascript.

Putting it all together we get:

r.table("stores")
 .concatMap(function (x) {
   return x("locations")
 })
 .eqJoin(function (i) { return i; }, r.table("locations"))

To get back the documents from the stores:

r.table("stores")
 .concatMap(function (x) {
   return x("locations").map(function (loc) {
      return x.merge({locations: loc});
   });
 })
 .eqJoin("locations", r.table("locations"))

Problem

Attempting to use this example to join on an array of IDs: https://github.com/rethinkdb/rethinkdb/issues/1533#issuecomment-26112118 Stores table snippet ``` { "storeID": "80362c86-94cc-4be3-b2b0-2607901804dd", "locations": [ "5fa96762-f0a9-41f2-a6c1-1335185f193d", "80362c86-94cc-4be3-b2b0-2607901804dd" ] } ``` Locations table snippet ``` { "lat": 125.231345, "lng": 44.23123, "id": "80362c86-94cc-4be3-b2b0-2607901804dd" } ``` I'd like to select the stores and join their store locations. Original example from ReThinkDB contributor: ``` r.table("blog_posts") .concat_map(lambda x: x["comment_ids"].map(lambda y: x.merge("comment_id" : y))) .eq_join("comment_id", r.table("comments")) ``` My attempt to convert to JS ``` r.table("stores") .concatMap((function(x){ return x("locations").map((function(y){ return x("locations").add(y); })) })) .eqJoin("locations", r.table("locations")) ``` Result `RqlRuntimeError: Expected type ARRAY but found STRING`

Original source

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