Mis - Types of Databases

Topics: Internet, Internet Protocol, IPv6 Pages: 5 (1496 words) Published: January 17, 2013
Types of DBMS: Hierarchical Databases
There are four structural types of database management systems: hierarchical, network, relational, and object-oriented.

Hierarchical Databases (DBMS), commonly used on mainframe computers, have been around for a long time. It is one of the oldest methods of organizing and storing data, and it is still used by some organizations for making travel reservations. Related fields or records are grouped together so that there are higher-level records and lower-level records, just like the parents in a family tree sit above the subordinated children. Based on this analogy, the parent record at the top of the pyramid is called the root record. A child record always has only one parent record to which it is linked, just like in a normal family tree. In contrast, a parent record may have more than one child record linked to it. Hierarchical databases work by moving from the top down. A record search is conducted by starting at the top of the pyramid and working down through the tree from parent to child until the appropriate child record is found. Furthermore, each child can also be a parent with children underneath it. The advantage of hierarchical databases is that they can be accessed and updated rapidly because the tree-like structure and the relationships between records are defined in advance. Hierarchical databases are so rigid in their design that adding a new field or record requires that the entire database be redefined.

Types of DBMS: Network Databases

Network databases are similar to hierarchical databases by also having a hierarchical structure. There are a few key differences, however. Instead of looking like an upside-down tree, a network database looks more like a cobweb or interconnected network of records. In network databases, children are called membersand parents are called owners. The most important difference is that each child or member can have more than one parent (or owner). two limitations must be considered when using this kind of database. Similar to hierarchical databases, network databases must be defined in advance. There is also a limit to the number of connections that can be made between records.

Types of DBMS: Relational Databases

In relational databases, the relationship between data files is relational, not hierarchical Relational databases connect data in different files by using common data elements or a key field. Data in relational databases is stored in different tables, each having a key field that uniquely identifies each row. Relational databases are more flexible than either the hierarchical or network database structures.

Types of DBMS: Object-oriented Databases (OODBMS)
Able to handle many new data types, including graphics, photographs, audio, and video, object-oriented databases represent a significant advance over their other database cousins. an object-oriented database can be used to store data from a variety of media sources, such as photographs and text, and produce work, as output, in a multimedia format. Object-oriented databases have two disadvantages. First, they are more costly to develop. Second, most organizations are reluctant to abandon or convert from those databases that they have already invested money in developing and implementing. COMPUTING TYPES:

CLUSTER COMPUTING: clustering means linking together two or more systems to handle variable workloads or to provide continued operation in the event one fails. Each computer may be a multiprocessor system itself. For example, a cluster of four computers, each with two CPUs, would provide a total of eight CPUs processing simultaneously. When clustered, these computers behave like a single computer and are used for load balancing, fault tolerance, and parallel processing. Two or more servers that have been configured in a cluster use a heartbeat mechanism to continuously monitor each other’s health. Each server sends the other an I am OK message at regular...
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