Definition:

A database that is stored in more than one physical location.

Types:

• Separated – data split into more than one location. No data is duplicated,

• Partitioned – data split into more than one location. Entire database is duplicated at a central location. All data exists in two locations.

• Distributed – data split into more than one location. Index to entire database exists at central location. No data is duplicated, only indexed.

• Duplicated – entire database is duplicated at more than one location.

Advantages (Separated or distributed versus centralized):

• Improved response time
• Uses smaller hardware
• Reduced communications vulnerability
• Decreased communications cost

Disadvantages (Separated or distributed versus centralized):

• Complexity
• Harder to find what you need
• Increased security risk
• Cannot optimize without centralized data

Advantages (Partitioned or duplicated versus centralized):

• Database backup
• Improved response time
• Operational overloads can be shifted

Disadvantages (Partitioned or duplicated versus centralized):

• Increased communications vulnerability
• Complexity
• Increased communications costs
• Increased security risk
• Higher hardware costs