Arthitucture models of distributed database systems:
• Client-server model distributed databases: In a client-server distributed database, the nodes in the system are divided into clients and servers. The clients are responsible for submitting queries to the servers, and the servers are responsible for retrieving the data from the database.
• Peer-to-peer model distributed databases: In a peer-to-peer distributed database, all of the nodes in the system are equal. This means that any node can access data from any other node.
• Global Conceptual Schema − Depicts the global logical view of data.
• 2) Local Conceptual Schema − Depicts logical data organization at each site.
• 3) Local Internal Schema − Depicts physical data organization at each site.
• 4) External Schema − Depicts the user’s view of data.
• Multidatabase systems: A multidatabase system is a collection of independent databases that are connected together. Each database in a multidatabase system can use a different DBMS.
• Multi-database View Level − Depicts multiple user views comprising subsets of the integrated distributed database.
• 2) Multi-database Conceptual Level − Depicts integrated multi-database that comprises global
• logical multi-database structure definitions.
• 3) Multi-database Internal Level − Depicts the data distribution across different sites and multi-
• database to local data mapping.
• 4) Local database View Level − Depicts a public view of local data.
• 5) Local database Conceptual Level − Depicts local data organization at each site.
• 6) Local database Internal Level − Depicts physical data organization at each site.