Which of the following is not a type of database?Answer areaHierarchicalNetworkDistributedDecentralized

Step 1: Identify Types of Databases

To determine which option is not a type of database, we need to define the various types provided:

1. Hierarchical Database: This database organizes data in a tree-like structure, with records having a single parent and multiple children.
2. Network Database: This model allows each record to have multiple parent and child records, forming a graph structure.
3. Distributed Database: This system involves data being stored on multiple sites, but is managed as a single database by the user.
4. Decentralized Database: This typically refers to a database that does not rely on a central controlling node or server.

Step 2: Analysis of Options

Out of the mentioned types:

• Hierarchical is a well-established database model.
• Network is also a recognized database model.
• Distributed is a valid term used in database management.
• Decentralized, while it can describe certain architectures, is not a standard database model like the others.

Step 3: Conclusion

Considering the definitions and types of databases, the option that is not recognized as a traditional type of database is Decentralized.

Final Answer

Decentralized is not a type of database.