Do you need to finish a Snowflake migration before building a context layer?

No. Defining your key figures during a migration can make it go better. Approved definitions tell the migration team what each report needs, give you a way to check that old and new systems agree, and stay valid when sources move. Waiting risks migrating inconsistent logic and fixing it afterward.

This matters even more after a merger, when several banks' data may move to Snowflake at once.

Why defining first helps

1. It sets the target. The migration team knows which fields and logic each figure depends on.
2. It gives you a test. Run each definition on old and new systems and compare.
3. It survives the move. The definition stays the same; only where it points changes.

How to do both at once

1. Pick the figures that must not break, such as regulatory and board metrics.
2. Define and approve them against current systems.
3. Map them to the new Snowflake tables as each domain lands.
4. Compare results on both sides until the old system retires.

How Preql helps

Preql works with your existing systems and data warehouses, and is a Snowflake partner. Approved definitions are versioned with audit trails, so finance can see what was agreed before the migration and check it against the new platform.

FAQ

Will we have to redo the definitions after migration?

Usually not. The mappings change; the definitions and approvals should stay.

What if we're merging several banks onto Snowflake?

Agree one definition per key figure, map each bank's systems to it, and reconcile before cutover.