Beyond basic files: why a lakehouse contract beats a CSV on a share drive

Shared folders have carried us this far. They will not carry us any further.

The CSV-on-a-share-drive problem

A CSV on a share drive is a great way to move data once. It is a terrible way to move data twice. No schema guarantees, no freshness signal, no lineage, no owner; by the third copy, three different definitions of the same column.

What a contract gives you

• Schema with teeth. Types, nullability, unique constraints, and a version.
• Freshness SLOs. A promise about when the data is current, with a signal when it breaks.
• Policy at the edge. Classification, consent, and AI-use rights declared alongside the data.

Contracts are not paperwork. They are the thing that lets a downstream team trust a number without asking. That trust is the whole point of a data platform.