4.Dbms, their functions and classifications. Analytical and operational databases.

A database management system consists of software that operates databases, providing

• Storage

• Access

• Security

• Backup

Database management systems can be categorized according to

• The database model that they support, such as relational or XML

• The type(s) computer they support, such as a server cluster or a mobile phone

• The query language(s) that access the database , such as SQL or XQuery

• Performance trade-offs such as maximum scale or maximum speed or others

Also databases can be classified by function and database model

I. Function

Analytic(al)

Operational

II. Database model

Flat file,Hierarchical,Network,Relationaa

An analytical database is used to store information from different types of databases such as selected operational databases and external databases. Other names given to analytical databases are information databases, management databases or multi-dimensional databases. The data stored in an analytical database is used by the management for analysis purposes, hence the name. The data in an analytical database cannot be changed or manipulated

In its day to day operation, an organisation generates a huge amount of data. Think of things such as inventory management, purchases, transactions and financials. All this data is collected in a database which is often known by several names such as operational/ production database, subject-area database (SADB) or transaction databases.

An operational database is usually hugely important to organisations as they include the customer database, personal database and inventory database i.e. the details of how much of a product the company has as well as information on the customers who buy them. The data stored in operational databases can be changed and manipulated depending on what the company requires.

5.Database models. Flat file model. Hierarchical model

Essentially a data model is a "description" of both a container for data and a methodology for storing and retrieving data from that container. Actually, there isn't really a data model "thing". Data models are abstractions, oftentimes mathematical algorithms and concepts. You cannot really touch a data model. But nevertheless, they are very useful. The analysis and design of data models has been the cornerstone of the evolution of databases. As models have advanced so has database efficiency.

Flat file database model is a database that stores data in a plain text file. Each line of the text file holds one record, with fields separated by delimiters, such as commas or tabs.

Hierarchical database model

• Perhaps the most intuitive way to visualize this type of relationship is by visualizing an upside down tree of data. In this tree, a single table acts as the "root" of the database from which other tables "branch" out.

• Relationships in such a system are thought of in terms of children and parents such that a child may only have one parent but a parent can have multiple children. Parents and children are tied together by links called "pointers"

• The hierarchical structure is used primarily today for storing geographic information and file systems.