How to choose default fields in feed?

Question

Suppose you have already done defdb. I have a table "items" that has two fields: "id" (PK) and "item". I want to configure the object so that whenever I select it, I get only entries in the "item". Judging by the documentation , I thought the way korma/entity-fields is to do this.

 (require '[korma.core :as korma]) (korma/defentity items (korma/entity-fields :item)) (korma/select items) ;; Wanted: [{:item "foo"}] ;; Received: [{:id 1, :item "foo"}] 

I am using korma 0.3.0-beta7. How to make korma/select do what I want?

Answer 1

I don't think you can do this from defentity - the way that selection works without passing the list of fields explicitly is just select * .

How about a helper macro based on korma / select:

 (defmacro select-without-id [ent & body] `(let [query# (-> (korma/select* ~ent) (korma/fields (vec (:fields ~ent))) ~@body )] (korma/exec query#))) 

Answer 2

id is the name of the Pa-defauld PK column in Feed. That is why you see it in the list of results. You can remove it using the transform definition:

 (korma/defentity items (korma/entity-fields :item) (korma/transform #(dissoc % :id))) 

Answer 3

Try creating a new namespace with the following dependencies:

 (ns yourproject.path.kormastuff (:use [korma.core] [korma.db])) 

Then create your entities as such:

 (defentity items (entity-fields :item)) 

I think you are likely to click on the wall because you are trying to create a kernel alias and you are missing db. It is much better to push this stuff into your own file and call the queries you want with aliases, if you have chosen, from other namespaces, that is:

 (ns project.core (:use [project.path.kormastuff :as kormadb])) 

Then:

 (select kormadb/items) 

to get your results. That should work.

In REPL just type

 items 

on the command line to see the result that Feed will give you. There should not be any other fields. If you run (select the elements) in the REPL, you will see everything whether you want this to happen or not. To get a real result, you probably have to do (in the "% s" format) in a browser window or something like that.

If all this does not work, there is no shame in using normal (select db (fields [: item])). You will find that in any case you will be forced to destroy information.

EDIT :::

Sorry, I didn’t explain myself clearly.

You should not do

 (select kormadb/items) 

to get what you want. You only need to call the object itself, so you only need to call the elements in REPL, NOT (select elements) in REPL.

Would you like to do something like

 (def myQuery kormadb/items) $ myQuery 

and you will see that no other fields are selected by default.

You can also do

 (let [myQuery kormadb/items] (format "%s" myQuery)) 

I am changing here, but what I get is like this:

 {:table "items", :name "items", :pk :id, :db nil, :transforms (), :prepare s (), :fields ("\"items\".\"item\""), :rel {}} 

To use myQuery, you need to destroy the above hash map. I will leave this an exercise for you, because destructuring is important and difficult to learn if you do not collect your own hands, but I will give you a small place to start that will not give you an answer, but won’t give an error:

 (let [{myAlias :fields} myQuery] (format "%s" myAlias))