1. Data integration patterns

2. Context Several systems
The main need for integration is getting data between systems
All agree: The ”surface” of the systems must be consciously ”governed”/”designed”/”grow”

3. How to use a RDBMS as integration hub
Requires discipline
Consciously managed interface: GRANTs
Versioning of interfaces
Views/Materialized views/Exported data
Remote performance
Database links/materialized views/exported data

4. When to use a RDBMS as integration hub
You can live with DB-vendor marriage
Your primary db is single-point-of-failure already
You have mostly anemic service layer
Your dataset fits RDBMS user case
Your load is moderate

5. Why to use a RDBMS as integration hub
Predefined verbs (insert, select, update, delete), explicit schemas
(Like REST)
”Unique selling point”: Selects joins across systems
Can be retrofitted on top of existing portfolio