BrainTrust Investment Lab › Band 3 — Loading (Delivering to the Kimball STAR)
Band 3 — Loading (Delivering to the Kimball STAR) · book 464-469 · grain: one dimension per walk sheet
History is never overwritten here. When an attribute changes, the old truth keeps its row and its dates — ask what the world looked like on any given day and get the answer as it was, not as it is now.
completed
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dim_security
completedrunningawaiting its turn · owedfailedexcluded
The contract — what each step must produce
| # | step | page | what the book requires |
|---|---|---|---|
| 2 | a type PER ATTRIBUTE, not per table | p.464 | 'there are three basic responses: type 1 overwrite, type 2 add a new row, and type 3 add a new column' |
| 3 | the five columns, applied | p.466 | 'and make appropriate updates to these housekeeping columns: Change Date (change date as foreign key to date dimension outrigger) Row Effective… |
| 4 | the as-of date, never a drifting provider stamp | p.466 | 'Always use the system or as-of date to derive the type 2 effective time stamps.' |
| 5 | the type 1/3 side effect | p.465 | 'Type 1 updates invalidate any aggregates built upon the changed column, so the dimension manager (subsystem 17) must notify the affected fact… |
| 6 | the overwrite reaches back -- but never into bronze | p.465 | 'Type 1 updates must be propagated forward from the earliest permanently stored staging tables to all affected staging tables, so if any of them are… |