Page 47 - DLIS408_INFORMATION_TECHNOLOGY-APPLICATIONSL SCIENCES

Information Technology and Application

Notes to provide effective run-time execution to properly support (e.g., in terms of performance, availability,
and security) as many end-users (the database’s application users) as needed. Sometimes, the
combination of a database and its respective DBMS is referred to as a Database system (DBS).
A database is typically organized according to general Data models that have been evolved since
the late 1960s. Notable data modules are the Relational model (all the DBMS types listed above
support databases-based on this model), the Entity-relationship model (ERM; primarily utilized
to design databases), and the Object model (which has more expressive power than the relational,
but is more complicated and less commonly used). Some recent database products use XML as
their data model. A single database may be viewed for convenience within different data models
that are mapped between each other (e.g., mapping between ERM and RM is very common in the
database design process, and supported by many database design tools, often within the DBMS
itself). Many DBMSs support one data model only, externalized to database developers, but some
allow different data models to be used and combined.
The design and maintenance of a complex database requires special skills: the staff performing this
function are referred to as database application programmers (different from the DBMS developers/
programmers) and database administrators, and their task is supported by tools provided either
as part of the DBMS or as free-standing (stand-alone) software products. These tools include
specialized Database languages including Data Description Languages, Data Manipulation
Languages, and Query Languages. These can be seen as special-purpose programming languages,
tailored specifically to manipulate databases; sometimes they are provided as extensions of existing
programming languages, with added special database commands. Database languages are generally
specific to one data model, and in many cases they are specific to one DBMS type. The most widely
supported standard database language is SQL, which has been developed for the relational model
and combines the roles of Data Description Language, Data manipulation language, and a Query
language.
A way to classify databases involves the type of their contents, for example: bibliographic, document-
text, statistical, multimedia objects, etc. Another way is by their application area, for example:
Accounting, Music compositions, Banking, Manufacturing, Insurance, etc.
The explanation is carried out by demonstrating examples of various database types, describing
the motivation for developing the database concept since the 1960s, outlining major requirements
that databases typically need to meet, and then major functional topics of databases. Database
management systems (DBMSs), is briefly described how needed database requirements are met by
contemporary technology.

Task Write a short note on Database.

4.1 Concept of Database

The database concept has evolved since 1960s to ease increasing difficulties in designing, building,
and maintaining complex information systems (typically with many concurrent end-users, and
with a diverse large amount of data. It has evolved together with the evolvement of Database
management systems (DBMSs) which enable the effective handling of databases. The terms database
and DBMS define different entities, and they are inseparable: A database’s properties are determined
by its supporting DBMS and vice-versa.
With the progress in technology in the areas of processors, computer memory, computer storage
and computer networks, the sizes, capabilities, and performance of databases and their respective
DBMSs have grown in orders of magnitudes. For decades it has been unlikely that a complex
information system can be built effectively without a proper database supported by a DBMS.

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