3. Distributed vs. Centralized
Centralized database can produce a bottleneck
Large volume of data input
Large database
Large volume of queries
In distributed databases, data consistency, replication, and
retrieval can be more problematic
Consistency of schemas
Retrieval in case the data location is not known
Communication overhead to ensure database consistency
9. Relational Operations
• Select operation, to create a subset of records that meet a
states criterion
• Join operation, combines two or more tables
• Project operation, subset of columns