Slide 1 – TitleSlide 1 – Distributed Database Collection of logically related databases. Data is stored at different network-connected sites. DDBMS manages the distributed data. Distribution is hidden from users. Slide 2 – Types & Architecture Types: Homogeneous: Same DBMS at all sites. Heterogeneous: Different DBMSs at different sites. Architecture: Client–Server Peer-to-Peer Multi-DBMS Slide 3 – Distributed Database Design Distributed design decides how and where data is stored. Main techniques: Replication Fragmentation Goals: Better reliability Faster access Reduced network load Slide 4 – Replication Replication stores copies of the same data at multiple sites. Advantages: Higher reliability Faster response Reduced network load Disadvantage: More storage and complex updates Slide 5 – Fragmentation Fragmentation divides a database into smaller fragments. Types: Horizontal: Divides rows. Vertical: Divides columns and retains the primary key. Hybrid: Combines horizontal and vertical fragmentation. Slide 6 – Data Transparency Data transparency hides distribution complexity from users. Types: Fragmentation Transparency Replication Transparency Location Transparency Users can access distributed data as if it were a single database. Slide 7 – Concurrency Control Concurrency means multiple transactions execute simultaneously. Concurrency control maintains correctness and consistency. Challenges: Multiple data copies Site failures Communication failures Network partition Distributed deadlock Distributed commit Slide 8 – Concurrency Techniques Locking Techniques: Distinguished Copy Primary Site Primary Site with Backup Primary Copy Timestamp Protocol: Transactions are processed according to timestamps. Slide 9 – Validation & Recovery Validation-Based Protocol: Read Phase Validation Phase Write Phase Distributed Recovery handles: Site failure Communication failure Network failure Transaction failure Slide 10 – Distributed Commit & Summary Distributed Commit: Records local effects permanently. Maintains local logs. Maintains consistency across sites. Overall Flow: Distribute Data → Design → Control Transactions → Recover → Maintain Consistency