diff options
Diffstat (limited to 'models/nutrient-measurement.rkt')
| -rw-r--r-- | models/nutrient-measurement.rkt | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/models/nutrient-measurement.rkt b/models/nutrient-measurement.rkt index 8c963b6..bc7a463 100644 --- a/models/nutrient-measurement.rkt +++ b/models/nutrient-measurement.rkt @@ -13,6 +13,7 @@ [get-nutrient-measurement-values (-> nutrient-measurement-or-id/c nutrient-value-hash/c)] [get-nutrient-measurement-value (-> nutrient-measurement-or-id/c nutrient? maybe-nutrient-value?)] + [get-latest-nutrient-measurement (-> (or/c nutrient-measurement? #f))] [get-latest-nutrient-measurement-value (-> nutrient? maybe-nutrient-value?)] [get-latest-nutrient-measurement-values (-> nutrient-value-hash/c)] [delete-nutrient-measurement! (-> nutrient-measurement-or-id/c void?)])) @@ -147,6 +148,12 @@ #:where (and (= nm.id ,(->nm-id nm-or-id)) (= nv.nutrient_id ,(nutrient-id nutrient)))))) +(define (get-latest-nutrient-measurement) + (define measurements (get-nutrient-measurements)) + (if (null? measurements) + #f + (first measurements))) + (define (get-latest-nutrient-measurement-value nutrient) (query-maybe-value (current-conn) (select value_ppm |