Database Definition and DBMS

Database is a collection of information organized in such a way that a computer program can quickly select desired peices of data. 
You can think of database as an electronic filing system.

Traditional databases are organized by fields, records and files.
an alternative concept in database desing is known as Hypertest . In a Hypertext database any object, whether it be a piece of text, a picture, or a film can be linked to any other object.

To access information from the system you need DBMS(database management system) . This is a collection of programs that enables you to  store, modify and extract information from a database.

database is used as shorthand for DBMS, there are many different types of DBMSs, ranging from small systems that run on personal computers to huge systems that run on mainframes.

few database applications:
computerized library systesm, Automated teller machines, flight reservation systems,computerized parts inventory systems.

DBMSs can differ widely. The tersm relational , network, flat, and hierarchical all refer to the way a DBMS organizes information internally. The internal organization can effect how quickly and flexibly you can extract information.

requests for information from a database are made in the form of query,
ex: SELECT ALL WHERE NAME = "SMITH" AND AGE > 35
the set of rules for constructing quries is known as a query language.

Different DBMS's support different query languages, although there is a semi-standardized query language called SQL (structured query language) . Sophisticated languages for managing database systesm are called fourth generation languages.

DMBS formats:
the information from a database can be presented in a variety of formats. Most DBMSs include a report writer program that enables you to output data in the form of  a report. Many DBMSs also include a graphics component that enables you to output information in the form of graphs and  charts.


Generally a database manager provides users with the ability to control read/write access , specify report generation and analyze usage.Some databases offer ACID(atomicity, consistency,isolation and durability) compliance to guarantee that data is consistent and that transactions are complete.

Databases are prevalent in large mainframe systems , but are also present in smaller distributed worksations and midrange systems, such as IBM's AS/4oo and presonal computers.

Evalutaion of Databases:
Databases have evolved since their inception in the 1960s , beginning with hierarchical and network databases, through 1980s with object-oriented databases , and today with SQL and No-SQL databases and cloud databases.
in one view , databases can be classified according to content type: bibliographic , full text, numeric and images. In computing, databases are sometimes classified according ot their organizational approach. there are manu kinds of databases raning from most prevalent aproach , the relational database, to a distributed database, cloud database or NOSQL database.

A database management system (DBMS) is a computer software application that interacts with the user, other applications, and the database itself to capture and analyze data. A general-purpose DBMS is designed to allow the definition, creation, querying, update, and administration of databases. Well-known DBMSs include MySQL, PostgreSQL, MongoDB, MariaDB, Microsoft SQL Server, Oracle, Sybase, SAP HANA, MemSQL and IBM DB2