Distributed Database System

What is a Distributed Database in DBMS?

• Homogeneous: All sites use identical DBMS software and hardware. They are easier to design and manage because the systems are uniform.
• Heterogeneous: Different sites can use different DBMS software, hardware, and data models. This provides more flexibility but makes management and query processing more complex.

• Horizontal Fragmentation: The table is split by rows. Each fragment has a subset of the rows and is stored on a different site. This is useful when different locations need access to different sets of records (e.g., storing customer data for a specific region on a local server).
• Vertical Fragmentation: The table is split by columns. Each fragment has a subset of the columns and is stored on a different site. This is useful when different applications need access to different attributes of a record. The primary key is usually repeated in all fragments to allow for reconstruction of the original table.
• Hybrid Fragmentation: A combination of horizontal and vertical fragmentation. The table is first divided horizontally, and then each of those fragments is divided vertically.