work on docs

docs/DEV.md

@@ -15,6 +15,50 @@ The `public/js` folder contains all the client-side JS:
 - **public / js / map.js** - handles creation of maps and points for the `map` view. Uses ARC GIS JS API.
 - **public / js / util.js** - handles odd things, such as generation of `HTML` for the template, and disabling/enabling views.
 
+## Creating a new PSQL Query
+The process of adding new server-side queries and allowing the client-side to access those functions, without providing access to the data, can be a little tricky. I have outlined the process I use here in the hopes that it will be helpful.
+1. In `queries.js` create a new function to get information using a programmed query string. This should look something like the example below:
+```js
+...
+const getSomething = (request, response) => {
+    var query = 'SELECT something from SOMETABLE;'
+    serverOut(query); // print the query text
+    pool.query(query, (error, results) => {
+        if (error) {
+            throw error // error from query string
+        }
+        response.status(200).json(results.rows) // return the results
+    })
+}
+module.exports = {
+    ...
+    getSomething, // this must match the route in index.js
+    ...
+}
+```
+2. In `index.js`, create a route so that the client-side will be able to access the routes in `queries.js`. This should look something like this:
+```js
+app.get('/something', q.getSomething); // should match the name in module.exports
+```
+3. We can now access the route from client-side. For example, in the file `public/js/data.js`. This should look something like this:
+```js
+function getSomthing(){
+    $.ajax({
+        type: 'GET',
+        url: '/something', // should match the name in index.js
+        success: function(response) { 
+            console.table(response); // show the full result
+
+            // a renderer could be made to use this data here
+        },
+        error: function(xhr, status, err) {
+            console.log(xhr.responseText); // if query fails
+        }
+    });
+}
+```
+
+
 ## HTML Template
 For style and `CSS` information, refer to the [ customization guide](CUSTOM.md). 
 HTML template exists in `views/index.ejs`.
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