Type of Databases

Ad-hoc databases

This is one of the earliest database types. It will not store data so as to optimize storage or queries, but to be read as a whole by a particular application. For a low volume of data, Ad-hoc databases are very efficient and convenient. It is typically accessed by a single application. However, it becomes very unwieldy, inefficient, and unmanageable when it grows beyond the size of available memory, as access patterns change, and they need to be shared between applications.

Hash-based databases

Hashes of data records and compacts keys which uniquely identify a record. It is easy to manage and easy to retrieve a particular record. Hash-based DBMS includes this mechanism. It is popular because of its simplicity, and used when an application needs the records, one at a time from the database by using a well defined key. For example, in a user authentication process, when a particular user tries to enter the system, at that moment it will check against a particular user ID.

Hierarchical databases

Hierarchical databases contain regular records in a more structured way. This database type is more suitable if it contains tightly coupled records of information. The main problem in a hierarchical database model is that you cannot add a record to a child table until it has already been incorporated into the parent table. And hierarchical databases contain redundant data and have an inflexibility in querying.

Relational databases

This is the main type of database in database technologies. This will reduce data redundancy and increase the speed of complex queries. It consists of a large number of tools and APIs to support them. It is more useful when many records are being combined and cross-referenced to synthesize results.Relational DBMS are designed to model very highly structured data which has been modeled with mathematical care and up to standard; for if not the advantages of the relational model will be lost.

Object databases

Object databases more likely translate the techniques of object-oriented programming to data storage models. Data are organized as distinct objects and belong to a particular class, which might use inheritance to acquire aspects of other classes. Each object contains a set of attributes and relationships to other objects. Finally it provides natural API for access using object oriented languages such as C++, Java.