Pavel Tisner

.gitignore

@@ -162,3 +162,11 @@ dist
 vite.config.js.timestamp-*
 vite.config.ts.timestamp-*
 
+
+.venv/
+.user.yml
+.env
+profiles.yml
+target/
+dbt_packages/
+logs/

AI_ASSIST.md

@@ -4,31 +4,74 @@ Document one place you used an LLM during this assignment.
 
 ## The problem
 
-<!-- TODO: describe the specific problem you asked an LLM about.
-     Example: "My safe_divide macro compiled but returned NULL for all rows even
-     when tip_amount and fare_amount were both non-zero." -->
-
-TODO
+After adding the `dbt_utils.unique_combination_of_columns` test to `fct_daily_borough_stats`, I ran `dbt parse`. The project parsed, but dbt showed a deprecation warning about generic test arguments. I wanted to understand what the warning meant and how to update the YAML syntax correctly.
 
 ## The prompt
 
-<!-- TODO: paste the exact prompt you sent to the LLM. -->
-
-TODO
+```text
+(.venv) pavel@Pavels-MacBook-Air c55-data-week-10 % ./.venv/bin/dbt parse --profiles-dir .
+/Users/pavel/Desktop/data _learn/c55-data-week-10/.venv/lib/python3.9/site-packages/urllib3/__init__.py:35: NotOpenSSLWarning: urllib3 v2 only supports OpenSSL 1.1.1+, currently the 'ssl' module is compiled with 'LibreSSL 2.8.3'. See: https://github.com/urllib3/urllib3/issues/3020
+  warnings.warn(
+23:12:57  Running with dbt=1.10.22
+23:12:58  Registered adapter: postgres=1.9.1
+23:12:58  Unable to do partial parsing because a project dependency has been added
+23:13:00  [WARNING][MissingArgumentsPropertyInGenericTestDeprecation]: Deprecated
+functionality
+Found top-level arguments to test dbt_utils.unique_combination_of_columns
+Arguments to generic tests should be nested under the arguments property.
+23:13:00  Performance info: /Users/pavel/Desktop/data _learn/c55-data-week-10/target/perf_info.json
+23:13:00  [WARNING][DeprecationsSummary]: Deprecated functionality
+Summary of encountered deprecations:
+- MissingArgumentsPropertyInGenericTestDeprecation: 1 occurrence
+To see all deprecation instances instead of just the first occurrence of each,
+run command again with the --show-all-deprecations flag. You may also need to
+run with --no-partial-parse` as some deprecations are only encountered during
+parsing.
+What should I change?
+```
 
 ## The response
 
-<!-- TODO: summarise or paste what the LLM returned. -->
+The LLM explained that the test logic was correct, but the YAML used an older style for passing arguments to a generic test. It said that in newer dbt style, test parameters should be placed under an explicit `arguments:` key.
+
+It suggested changing this:
+
+```yaml
+tests:
+  - dbt_utils.unique_combination_of_columns:
+      combination_of_columns:
+        - pickup_borough
+        - pickup_date
+```
+
+to this:
 
-TODO
+```yaml
+tests:
+  - dbt_utils.unique_combination_of_columns:
+      arguments:
+        combination_of_columns:
+          - pickup_borough
+          - pickup_date
+```
 
 ## Reflection
 
-<!-- TODO: what did you change, keep, or discard after reviewing the LLM's answer?
-     Be specific: "I kept the NULLIF suggestion but changed the column alias from
-     'ratio' to 'tip_pct' to match the assignment schema." -->
+I kept the `arguments:` suggestion because it removed the dbt deprecation warning while keeping the same test logic: one row per combination of `pickup_borough` and `pickup_date`.
+
+I did not change the grain of the mart or the tested columns. I only changed the YAML syntax for the generic test arguments.
+
+After the change, `dbt parse` ran without the deprecation warning, and the mart tests completed successfully:
+
+```text
+Done. PASS=4 WARN=0 ERROR=0 SKIP=0 NO-OP=0 TOTAL=4
+```
+
+Later, the full project build completed with one expected warning from the singular `avg_tip_pct` test:
 
-TODO
+```text
+Done. PASS=11 WARN=1 ERROR=0 SKIP=0 NO-OP=0 TOTAL=12
+```
 
 ---
 

macros/safe_divide.sql

@@ -3,8 +3,5 @@
 -- Use for tip_pct = tip_amount / fare_amount and similar ratio columns.
 
 {% macro safe_divide(numerator, denominator) %}
-    -- TODO: implement the macro body.
-    -- Use NULLIF(denominator, 0) to avoid division-by-zero errors.
-    -- Return only the SQL expression (no SELECT, no semicolon).
-    NULL
+    ({{ numerator }} / nullif({{ denominator }}, 0))
 {% endmacro %}

models/marts/_fct_daily_borough_stats.yml

@@ -2,23 +2,27 @@ version: 2
 
 models:
   - name: fct_daily_borough_stats
-    description: >
-      TODO: state the grain (one row per ___), the source lineage
-      (built from ___ and ___), and at least one known caveat
-      (e.g. rows dropped in staging, any WARN-severity tests).
-    # TODO: Task 5 -- add the compound uniqueness test on the mart's primary
-    # key (pickup_borough, pickup_date). You need the dbt_utils package for
-    # this: declare it in packages.yml and run `dbt deps` first.
+    description: "Daily borough-level mart for NYC Green Taxi trips. The grain is one row per pickup borough and pickup date. The model is built from stg_trips joined to stg_zones using pickup_location_id. Trips with null pickup location ids or negative fares are removed in staging, and trips with pickup location ids that do not match a known TLC zone are dropped by the inner join. High average tip percentages are checked by a warning-level singular test because unusual tips can occur in low-volume borough/date combinations."
+    tests:
+      - dbt_utils.unique_combination_of_columns:
+          arguments:
+            combination_of_columns:
+              - pickup_borough
+              - pickup_date
     columns:
       - name: pickup_borough
-        description: "TODO: explain what this column contains and where it comes from"
+        description: "Borough label of the TLC pickup zone. This comes from stg_zones.borough and can include NYC boroughs as well as labels such as EWR, Unknown, or NaN."
+        tests:
+          - not_null
       - name: pickup_date
-        description: "TODO: explain units and how it is derived"
+        description: "Calendar date of the trip pickup, derived from pickup_datetime. Unit: date."
+        tests:
+          - not_null
       - name: trip_count
-        description: "TODO: explain what is counted (unit: number of trips)"
+        description: "Number of taxi trips picked up in the borough on the date. Unit: trips."
       - name: total_fare
-        description: "TODO: explain units (USD) and what fare_amount represents"
+        description: "Sum of fare_amount for trips picked up in the borough on the date. Unit: US dollars."
       - name: avg_tip_pct
-        description: "TODO: explain the ratio (tip_amount / fare_amount)"
+        description: "Average of tip_amount divided by fare_amount for trips picked up in the borough on the date. Unit: decimal ratio, where 0.2 means 20%."
       - name: avg_trip_distance
-        description: "TODO: explain units (miles, from TLC source data)"
+        description: "Average trip_distance for trips picked up in the borough on the date. Unit: miles."

models/marts/fct_daily_borough_stats.sql

@@ -14,25 +14,15 @@ zones AS (
 )
 
 SELECT
-    -- TODO: join trips to zones on pickup_location_id = location_id.
-    --   Use an INNER JOIN: a few trips have a pickup_location_id with no matching
-    --   zone (e.g. 999). INNER JOIN drops those so pickup_borough is never NULL and
-    --   can serve as part of the mart's primary key (your not_null test needs this).
-    -- TODO: aggregate to grain (pickup_borough, pickup_date)
-    -- Required output columns:
-    --   pickup_borough   TEXT     - z.borough
-    --   pickup_date      DATE     - pickup_datetime::date
-    --   trip_count       BIGINT   - count(*)
-    --   total_fare       NUMERIC  - sum(fare_amount)
-    --   avg_tip_pct      NUMERIC  - avg(tip_pct)
-    --   avg_trip_distance NUMERIC - avg(trip_distance)
-    NULL AS pickup_borough,
-    NULL AS pickup_date,
-    NULL AS trip_count,
-    NULL AS total_fare,
-    NULL AS avg_tip_pct,
-    NULL AS avg_trip_distance
-
+    z.borough as pickup_borough,
+    t.pickup_datetime::date as pickup_date,
+    count(*) as trip_count,
+    sum(t.fare_amount) as total_fare,
+    avg(t.tip_pct) as avg_tip_pct,
+    avg(t.trip_distance) as avg_trip_distance    
 FROM trips t
--- TODO: add JOIN to zones here
--- TODO: add GROUP BY here
+inner join zones z
+    on t.pickup_location_id = z.location_id
+group by
+    z.borough,
+    t.pickup_datetime::date

models/staging/_sources.yml

@@ -2,9 +2,9 @@ version: 2
 
 sources:
   - name: nyc_taxi
-    schema: nyc_taxi     # TODO: confirm this matches the schema where raw_trips and raw_zones live
+    schema: nyc_taxi
     tables:
       - name: raw_trips
-        description: "TODO: one sentence on what this table contains and its grain"
+        description: "Raw NYC Green Taxi trip records, with one row per taxi trip."
       - name: raw_zones
-        description: "TODO: one sentence on what this table contains"
+        description: "Raw TLC taxi zone lookup table, with one row per location_id."

models/staging/_stg_trips.yml

@@ -2,19 +2,21 @@ version: 2
 
 models:
   - name: stg_trips
-    description: "TODO: state the grain (one row per ___) and what source this reads from"
+    description: "Cleaned trip-level staging model for NYC Green Taxi trips, with one row per trip from raw_trips after removing rows with missing pickup location ids or negative fares."
     columns:
       - name: pickup_datetime
-        description: "TODO"
-        # TODO: Task 5 -- add not_null tests on every column used as a join or
-        # group-by key. See the chapter's dbt Tests section for the syntax.
+        description: "Timestamp when the trip started; used to derive pickup_date in the daily borough mart."
+        tests:
+          - not_null
       - name: pickup_location_id
-        description: "TODO"
+        description: "TLC zone identifier where the trip started; used to join trips to stg_zones."
+        tests:
+          - not_null
       - name: fare_amount
-        description: "TODO"
+        description: "Fare amount charged for the trip, in US dollars."
       - name: tip_amount
-        description: "TODO"
+        description: "Tip amount paid for the trip, in US dollars."
       - name: trip_distance
-        description: "TODO"
+        description: "Trip distance, in miles."
       - name: tip_pct
-        description: "TODO"
+        description: "Tip amount divided by fare amount; null when fare amount is zero."

models/staging/_stg_zones.yml

@@ -2,11 +2,14 @@ version: 2
 
 models:
   - name: stg_zones
-    description: "TODO: state the grain and what source this reads from"
+    description: "Cleaned TLC taxi zone lookup staging model, with one row per location_id from raw_zones."
     columns:
       - name: location_id
-        description: "TODO"
-        # TODO: Task 5 -- this column is the join key. Which two generic tests
-        # guarantee a clean one-to-many join from stg_trips?
+        description: "Unique TLC zone identifier used to join trips to pickup boroughs."
+        tests:
+          - not_null
+          - unique
       - name: borough
-        description: "TODO"
+        description: "Borough label for the TLC zone, including NYC boroughs plus values such as EWR, Unknown, and NaN."
+        tests:
+          - not_null

models/staging/stg_trips.sql

@@ -3,11 +3,12 @@
 -- Downstream: fct_daily_borough_stats joins this to stg_zones.
 
 SELECT
-    -- TODO: select the columns you need for the mart:
-    --   pickup_datetime, pickup_location_id, fare_amount, tip_amount, trip_distance
-    --
-    -- TODO: add tip_pct using {{ safe_divide('tip_amount', 'fare_amount') }}
-    --
-    -- TODO: filter out rows where pickup_location_id IS NULL or fare_amount < 0
-
+    pickup_datetime, 
+    pickup_location_id, 
+    fare_amount, 
+    tip_amount, 
+    trip_distance,
+    {{ safe_divide('tip_amount', 'fare_amount') }} as tip_pct
 FROM {{ source('nyc_taxi', 'raw_trips') }}
+where pickup_location_id is not null
+  and fare_amount >= 0

models/staging/stg_zones.sql

@@ -1,7 +1,4 @@
--- Staging model: one row per TLC zone (265 zones).
--- Exposes location_id and borough for use as a lookup in the mart.
-
 SELECT
-    -- TODO: select location_id and borough from {{ source('nyc_taxi', 'raw_zones') }}
-
+    location_id,
+    borough
 FROM {{ source('nyc_taxi', 'raw_zones') }}

package-lock.yml

@@ -0,0 +1,5 @@
+packages:
+  - name: dbt_utils
+    package: dbt-labs/dbt_utils
+    version: 1.3.0
+sha1_hash: 226ae69cdfbc9367e2aa2c472b01f99dbce11de0

packages.yml

@@ -1,5 +1,3 @@
-# TODO: Task 5 -- declare the dbt-labs/dbt_utils package here, then run
-# `dbt deps` to install it. You need it for the compound uniqueness test
-# on the mart. See https://hub.getdbt.com/dbt-labs/dbt_utils/latest/
-# for the package block syntax.
-packages: []
+packages:
+  - package: dbt-labs/dbt_utils
+    version: 1.3.0