Batch DB updates in practice stats and deltas

src/benchmark.rs

@@ -447,8 +447,8 @@ mod tests {
         let anchor = 1_000_000;
         assert_eq!(Benchmark::session_timestamp(anchor, 0, 1), anchor);
         assert_eq!(Benchmark::session_timestamp(anchor, 1, 1), anchor + 86400);
-        assert_eq!(Benchmark::session_timestamp(anchor, 1, 2), anchor + 172800);
-        assert_eq!(Benchmark::session_timestamp(anchor, 7, 1), anchor + 604800);
+        assert_eq!(Benchmark::session_timestamp(anchor, 1, 2), anchor + 172_800);
+        assert_eq!(Benchmark::session_timestamp(anchor, 7, 1), anchor + 604_800);
     }
 
     /// Verifies that exercise timestamps are calculated correctly within a session.

src/data.rs

@@ -99,8 +99,11 @@ impl TryFrom<f32> for MasteryScore {
 
 //@<lp-example-4
 /// The result of a single trial.
-#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+#[derive(Clone, Debug, Default, Deserialize, PartialEq, Serialize)]
 pub struct ExerciseTrial {
+    /// The ID of the exercise to which the trial belongs.
+    pub exercise_id: Ustr,
+
     /// The score assigned to the exercise after the trial.
     pub score: f32,
 
@@ -110,8 +113,11 @@ pub struct ExerciseTrial {
 //>@lp-example-4
 
 /// The delta between the predicted and actual score for a single exercise trial.
-#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+#[derive(Clone, Debug, Default, Deserialize, PartialEq, Serialize)]
 pub struct ExerciseDelta {
+    /// The ID of the exercise to which the delta belongs.
+    pub exercise_id: Ustr,
+
     /// The delta between the predicted and actual score.
     pub delta: f32,
 
@@ -1483,6 +1489,7 @@ mod test {
     #[test]
     fn exercise_trial_clone() {
         let trial = ExerciseTrial {
+            exercise_id: Ustr::from("exercise"),
             score: 5.0,
             timestamp: 1,
         };

src/error.rs

@@ -60,8 +60,8 @@ pub enum PracticeStatsError {
     #[error("cannot get scores for unit {0}: {1}")]
     GetScores(Ustr, #[source] anyhow::Error),
 
-    #[error("cannot record score for unit {0}: {1}")]
-    RecordScore(Ustr, #[source] anyhow::Error),
+    #[error("cannot record scores: {0}")]
+    RecordScore(#[source] anyhow::Error),
 
     #[error("cannot trim scores: {0}")]
     TrimScores(#[source] anyhow::Error),
@@ -77,8 +77,8 @@ pub enum PracticeDeltasError {
     #[error("cannot get deltas for unit {0}: {1}")]
     GetDeltas(Ustr, #[source] anyhow::Error),
 
-    #[error("cannot record delta for unit {0}: {1}")]
-    RecordDelta(Ustr, #[source] anyhow::Error),
+    #[error("cannot record deltas: {0}")]
+    RecordDelta(#[source] anyhow::Error),
 
     #[error("cannot trim deltas: {0}")]
     TrimDeltas(#[source] anyhow::Error),