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One row of what, and when
Twelve on census day, nine today: both right. Say what one row is and which day it describes, before any SQL, and test both.
Topics › Analytics engineering › In the weeds of data crafting
Promises and proofs: promise it in a contract, prove it with a test, first
Since 1300, English silver has been tested before it's marked. A core model makes the same kind of promise: every gap between what the business expects and what the sources hold gets a decision, the contracts say what's promised, and the tests prove it, written before the code they check.
Builds on One row of what, and when
Watch the film
Press Play, or pick a chapter. Turn on Pause and think to stop for one question at the end of chapters.
Download the videoCaption filesRead the script
Where next?
You've seen the promises and the proofs. Now write some yourself.
See it in the project
Every card in the film shows a real file from the example dbt project. Open the ones each chapter shows, on GitHub, or run the whole project yourself.
- The gap register
requirements/requirements/sources/learning_platform/_learning_platform__requirements.ymlsources/learning_platform/_learning_platform__decisions.yml - The enterprise contract
dbt_project.ymlmodels/core/student/_core_student__models.yml - Two consumer contracts
dbt_project.ymlexposures/planning/_planning__exposures.ymlexposures/wallet/_wallet__exposures.yml - Tests first
models/core/course/_core_course__models.ymltests/generic/versions_do_not_overlap.sqlseeds/expected/planning/census_report.csvtests/reconciliation/reconcile_planning_with_census_report.sql - Logic, tested alone
models/intermediate/student/_int_student__models.yml - Warn or stop
models/staging/short_courses/_short_courses__models.ymlsources/short_courses/_short_courses__decisions.ymlsources/student_system/_student_system__sources.yml
Think it through
The four Pause and think questions, for a class or a team. Open one to see the answer.
In the series: In the weeds of data crafting
Film 5 of 10.
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Built in layers
Four layers turn the tests green. Each layer has one job; each CTE, one step; and the rule is written once.