Metacenta

BI semantic layer · rule tableau-reads-unknown

Tableau data sources reading unmodelled tables

A Metacenta review checks this under the rule Tableau data sources read tables the warehouse layer builds. Everything below applies whether or not you ever commission one.

What this rule checks

For each Tableau data source that reads named database tables, this rule flags it when a table matches nothing the transformation layer builds or declares as a source. We compare names only, not schemas.

Why it matters

Its dashboards sit outside the tested pipeline. A change upstream cannot warn anyone that it will break them.

How to fix it

Point Tableau data sources at modelled tables. Point the data source at the modelled table that serves it. If another pipeline builds that table on purpose, tell us, and the finding comes out of your report.

When it is fine to leave

A small table maintained by hand, such as a list of targets, loaded straight into the warehouse. Load it through the pipeline as a seed when you can, so it is tested too.

What we need to check it

Tableau .twb or .twbx workbooks, plus a warehouse-side artefact: manifest.json, a SQL project or a lineage export. Without one, the rule declines. Excel sheets, text files, extracts and custom SQL are not matched. Findings are medium confidence.