filters.md

Any valid Walkable S-expression that evaluates to boolean (not just some truthy values) can be used in a filter.

Using filters directly in query's parameters

`[{(:people/all {:filters [:or [:like :person/name "jon%"]
                               [:< :person/yob 1970]]})
   [:person/name :person/yob]]}

{% hint style="info" %} This is called supplied-conditions in Walkable query builder engine's source code. {% endhint %}

Filters in :extra-conditions floor-plan

You may want to enforce filters for specific idents/joins:

• For DRY reason: you don't want to retype the same filter set again and again.
• For security reason: once you define some constraints to limit what the clients can access for an ident or join, they're free to play with whatever left open to them.

;; floor-plan
{:extra-conditions {:people/all [:= :person/hidden false]
;; any valid filter will work
                    :person/friends [:or
                                     [:like :person/name "jon%"]
                                     [:like :person/name "mary%"]]}}

Joins in filters

You've seen filters used against columns of the current table. If you have defined some :joins in your floor-plan, you can also put constraints on columns of the joined tables, too.

;; find all people whose name starts with "jon" or whose friend's name
;; starts with "jon".
`[{(:people/all {:filters [:or [:like :person/name "jon%"]
                               {:person/friend [:like :person/name "jon%"]}]})
[:person/name :person/yob]}]

You can have many such joins in filters and combine them with other expressions using :and/:or/:not however you like.