Question

I’m trying to use the query engine
SQLike and am struggling with the basic concept.

The JSON I’m using as my data source comes from my PHP code, like so:

var placesJSON=<? echo json_encode($arrPlaces) ?>;

Here’s a sample JSON:

var placesJSON=[{"id":"100","name":"Martinique","type":"CTRY"},{"id":"101","name":"Mauritania","type":"CTRY"},{"id":"102","name":"Mauritius","type":"CTRY"},{"id":"103","name":"Mexico","type":"CTRY"},{"id":"799","name":"Northern Mexico","type":"SUBCTRY"},{"id":"800","name":"Southern Mexico","type":"SUBCTRY"},{"id":"951","name":"Central Mexico","type":"SUBCTRY"},{"id":"104","name":"Micronesia, Federated States","type":"CTRY"},{"id":"105","name":"Moldova","type":"CTRY"}];

I understand (via this reference) that I first need to unpack my JSON like so:

var placesData = SQLike.q(
       {
       Unpack: placesJSON,
       Columns: ['id','name','type']
       }
    )

And the next step would be to query the results like so:

var selectedPlaces = SQLike.q(
               {
               Select: ['*'],
               From: placesData,
               OrderBy: ['name','|desc|']
               }

Lastly, to display the results in the browser I should use something like:

  document.getElementById("myDiv").innerHTML=selectedPlaces[0].name

This doesn’t work. The error I get is: selectedPlaces[0].name is undefined.

I’m pretty sure I’m missing out on something very simple. Any hints?

Answer 1

“Unpack” converts an array of arrays, like [["John", "Peterson", 38, 28000], ["Vicki", "Smith", 43, 89000]] into an array of objects. Since your Json is already in this format, there’s no need to unpack it.