Processing methods
| Method | Characteristics |
|---|---|
| Batch processing | Transactions accumulated and processed in groups; control totals easy; data not current between runs |
| Real-time / online | Immediate processing and master file update; data always current; requires stronger access controls and logging |
Databases
- Relational database — data in tables of rows and columns, linked by primary keys and foreign keys
- DBMS — the software layer managing storage, retrieval, and security
- Referential integrity — a foreign key must match an existing primary key, preventing orphan records
- Normalization — organizing data to eliminate redundancy and update anomalies
- Data warehouse — an integrated store optimized for analysis rather than transaction processing; a data lake holds raw data in native formats
IMPORTANT — the ACID properties of reliable transaction processing: Atomicity (all or nothing), Consistency (valid state to valid state), Isolation (concurrent transactions don't corrupt one another), and Durability (committed data survives failure).
ERP systems
An ERP integrates finance, procurement, HR, and operations into one database. Benefits: single source of truth, reduced reconciliation, standardized processes. Risks: concentration — a single point of failure and a place where inappropriate access can cross the whole business — plus complex, high-risk implementations.
Cloud service and deployment models
| Model | Customer manages | Example |
|---|---|---|
| IaaS | OS, middleware, applications, data | Virtual servers and storage |
| PaaS | Applications and data only | Managed application platform |
| SaaS | Data and user access configuration only | Hosted accounting or CRM software |
Deployment models: public, private, hybrid, and community cloud.
EXAM TIP: Cloud adoption is a shared responsibility model. Moving to SaaS shifts infrastructure controls to the provider, but the customer always retains responsibility for its own data, user access provisioning, and vendor oversight — which is why SOC reports matter.