Conditional Operations

put-item!, delete-item! and update-item! accept a :when option, consisting of a nest of vectors, describing conditions which are required to hold for the operation to succeed.

query! & scan! accept a :filter option with identical structure (used for Dynamo-side filtering of query results).

In addition to :and, :or & :not, the supported operations are:

• [:begins-with path substring]
• [:exists path]
• [:contains path substring-or-set-member]
• [:in path [v1 v2 .. v100]]
• [:between path lo hi]
• :<, :<=, :=, :>, :>=, :<>

Paths

Paths are vectors describing locations within an item - a top-level attribute [:attr], or nested value [:attr :key], [:list-attr 0 :list-key 2].

Generally, the operators will interpret a vector passed as the first argument to be an attribute path, and a vector as the second to be a literal.

In the rare cases when it's necessary, explicitly distinguishing attribute paths from literal vectors can be done with the #hildebrand/path and #hildebrand/literal reader tags (or by applying metadata).

Examples

[:and
 [:<= [:age] 34]
 [:in [:age] [30 33 34]]
 [:not [:in [:age] #{30 34}]]
 [:or
  [:begins-with [:hobby] "Sta"]
  [:begins-with [:hobby] "Stra"]]]

[:and
  [:or
   [:between [:age] 10 30]
   [:between [:age] 33 40]]
 [:exists [:garbage]]]

[:= 30 30]

[:= [:data :age] 30]