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					              DATA BASE

“A Collection of integrated data items that
can be retrieved for various applications”

     “A Database is a collection of related
                 files”
                   DBMS
 DBMS is a set of systems software programs that
organizes and maintains in a database for
providing the information.
 DBMS is system software used to manage the
organization, storage, access, security and
integrity of data in a structured database.
 That permits an organization to centralize data ,
manage them efficiently, and provide access to
the stored data by application programs.
DBMS- “Special software to create & maintain a
     database & enable individual business
  applications to extracts the data they need
 without having to create separate files or data
    definitions in their computer programs”


•   A DBMS has three components:
•   Data Definition Language
•   Data Manipulation Language
•   Data dictionary
           Function of DBMS
• Stores data in a uniform and consistent way.
• Organizes the data
• Accesses the files updates the records
• Retrieves data as requested
• Adding and deleting records
• Reorganizing the data base by reassigning
  storage space processing more efficient.
• Provides data security
           TYPES OF DATABASE
•   Operational database
•   Analytical database
•   Data warehouse
•   Distributed database
•   End-user database
•   External database
          1.Operational Database
       These databases store detailed data
    needed to support the operations of an entire
    organization. They are also called subject-area
    databases (SADB), transaction databases, and
    production databases. For example:
•   customer databases
•   personal database
•   inventory databases
•   accounting databases
       ANALYTICAL DATABASE

    These databases store data and
information extracted from selected
operational and external databases. They
consist of summarized data and information
most needed by an organization's
management and other end-users.
           DATA WAREHOUSE
• A data warehouse stores data from current
  and previous years — data extracted from the
  various operational databases of an
  organization. It becomes the central source of
  data that has been screened, edited,
  standardized and integrated so that it can be
  used by managers and other end-user
  professionals throughout an organization.
         DISTRIBUTED DATABASE

• These are databases of local work-groups and
  departments at regional offices, branch
  offices, manufacturing plants and other work
  sites. These databases can include segments
  of both common operational and common
  user databases, as well as data generated and
  used only at a user’s own site.
         END-USER DATABASE
• These databases consist of a variety of data
  files developed by end-users at their
  workstations. Examples of these are
  collections of documents in spreadsheets,
  word processing and even downloaded files.
             External database

• These databases provide access to external,
  privately-owned data online — available for a
  fee to end-users and organizations from
  commercial services. Access to a wealth of
  information from external database is
  available for a fee from commercial online
  services and with or without charge from
  many sources in the Internet.
        Components of DBMS
• Data Definition Language
• Data Manipulation Language
• Data dictionary
• Data Definition Language ( DDL ) – is the
  formal language programmers use to specify
  the structure of the content of the database.
• Data Manipulation Language (DML ) – This
  language contains commands that permit end
  users and programming specialists to extract
  data from the database to satisfy information
  requests and develop applications.
• Data Dictionary – This is an automated or
  manual files that stores definitions of data
  elements and data characteristics, such as
  usage, physical representation, ownership,
  authorization and security.
  RDBMS – RELATIONAL DBMS
                RDBMS may be a DBMS in
which data is stored in the form of tables and
the relationship among the data is also stored
in the form of tables.
          It represents all data in the database
as simple two dimensional tables called
relations. Tables may be referred to as files.
Information in more than one file can be
extracted and combined.
• RDMBS – structured query language(SQL) is
  the principal data manipulation language for
  relational DBMS & major tool for querying ,
  updating , reading a relational database.
• The most popular RDBMS are MS
  SQLserver,DB2, Oracle, and MySQL
                         EXAMPLE OF A (RDBMS)


       CUSTOMER ID(PK)                          ORDER NUMBER (FK)
         LAST NAME                                 ORDER DATE
         FIRST NAME                              ORDER FILL DATE
       PHONE NUMBER
• RDBMS stores information in a set of “ tables”
  each of which has unique identifier or “
  primary key”
• The tables are then related to one another
  using “foreign keys”.
• In the example above “customer ID” is the
  primary key(PK) in one table and the foreign
  key in another. The arrow represents a one-to-
  many relationship between the two tables.
• The relationship indicates that one customer
  can have one or more orders, a given order,
  however can be initiated by one and only one
  customer.
           RDBMS components

•   Interface drivers
•   SQL engine
•   Transaction engine
•   Relational engine
•   Storage engine
• Interface drivers - A user or application program initiates
  either schema modification or content modification.
  They provide methods to prepare statements, execute
  statements, get results, etc. Examples include DDL, DCL,
  DML, ODBC, and JDBC.
• SQL engine - This component interprets and executes
  the SQL query. It comprises three major components
  (compiler, optimizer, and execution engine).
• Transaction engine - Transactions are sequences of
  operations that read or write database elements, which
  are grouped together.
• Relational engine - Relational objects such as Table,
  Index, and Referential integrity constraints are
  implemented in this component.
• Storage engine - This component stores and retrieves
  data records. It also provides a mechanism to store data
  and control information such as undo logs, redo logs,
    Difference between DBMS &
              RDBMS
• DBMS is single user system. RDBMS is a multi
  user system.
• DBMS do not store data in the table format
  while RDBMS stores data in the form of table.
• Most of the DBMS are not supporting client /
  server architecture as it is supported by
  RDBMS
• Most of the DBMS do not support distributed
  databases while RDBMS is do that.
OODBMS – Object Oriented DBMS
     In programming languages is to utilize
 objects, thereby making OODBMS in the
 1980s. OO ( Object Oriented ) programmers
 can develop the product, store them as
 objects, and can replicate or modify existing
 objects to make new objects within the
 OODBMS.
     Information today includes not only data
 but video, audio, graphs, and photos which
 are considered complex data types that
 relational database could not.
• Its consistent , data independent, secure,
  controlled & extensible data management
  services to support the object – oriented
  model.
• They were created to handle big & complex
  data that relational databases could not.
• Its stores the data & procedure as objects that
  can be automatically retrieved & shared.
• OODBMS are becoming popular because they
  can be used to manage the various
  multimedia components or java applets used
  in web applications , drawings images ,
• OBJECT –ORIENTED PROGRAMMING
  RESULTS IN 4 CHARACTERSITICS:

•   1.INHERITANCE
•   2.DATA ENCAPSULATION
•   3.OBJECT IDENTITY
•   4.POLYMORPHISM

 INHERITANCE: its allows one to develop
  solutions to complex problems incrementally
  by defining new objects in terms of previously
  defined objects.
 DATA ENCAPSULATION: or simply
  encapsulation allows the hiding of the internal
  state of the objects . Encapsulation objects are
  those objects that can only be assessed by their
  methods instead of their internal states.
Types - DATA ENCAPSULATION
• Full encapsulation –in which all the operations on
  objects are done through message sending &
  method execution.
• Write encapsulation – which is where the internal
  state of the objects is visible only for reading
  operations.
• Partial encapsulation – which involves allowing
  direct access for reading & writing for only a part
• OBJECT IDENTITY: allows objects of the
  database to be independent of each other.
• POLYMORPHISM: dynamic binding allow one to
  define operations for one object and then to share
  the specifications of the operations with other
  objects.

 ADVANTAGES:
• Object –oriented is a more natural way of thinking
• The defined operations of those types of systems
  are dependent on the particular database
  applications running at a given moment.
• Data types of object –oriented databases can be
  extend to support complex data, such as images ,
  digital & audio/ video along with other multi-

				
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posted:10/16/2011
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