Rachiyta Book

 Types of Attributes:- Simple Attribute:-  The attributes that cannot be further divided in to smaller part an represents the basic meaning is called a simple attributes. Eg:- Age attributes of person entity represent a simple attribute. Composite Attribute:-  Attribute that can be further divided into smaller unit & each individual unit contains a specific meaning. Eg:- Name attribute of an employ can be sub divided. Multivalued Attribute:-  Attribute that have more than one values for a particular entity is called a multivalued attributes. Eg:- Phone no. for a person entity is a multivalued entity. Stored Attributes:-  Attribute that are directly stored attribute. Eg:- Date of joining attributes of employ entity.  Single valued attribute:-  Attribute having a single value for a particular entity. Eg:- Age is an single valued attribute of a student entity. Derived Attribute:-  Attributes are not stored directly but  can be derived from stored attributes are called derived attribut

 E-R Model (Entity-Relationship Model) :- It a  high level conceptual data model.  It allows us to describe the data involved in a real world inter price , in terms of objects & there relationship. It is validly used to developed an initial design of data base it provides a set of useful concepts that make it convenient for a developer. It describes data as a collection of entities relationship & attributes. Entities:- An entities is an object of consult used to represent the things in the real word. Eg:- Car, Table, etc. An entity need not be a physical entity it can also represent a concept in real words. Eg:- Project, Loan, etc. Entity Set:- A collection of similar kind of entities is called an entity set all entity type -> In college  database students, faculty, Course & Department are consort of check. The collection of all the students similarly collection of all course from an entity set course. Entity Identifier key attributes:- An entity type usually has an attr

   Structure of Data Base Management System:-          The measure components of DBMS described below:- Data Manager:-  It is the central software component of the DBMS. It is some times called database control system. Main function of the data manager is to convert operation in the user queries directly via the query processor or indirectly by an application program from the user logical view to a physical file system the data manager is also responsible for interfacing with the file system. The tasks of informing constraints to maintain the consistently and integrity of the data as well as its securely are also performed by data manager backup & recovery operations are  also performed by data manager. File Manager:- It is responsible for the structure of file & managing the file space it is also responsible for location the block containing the required record. Disk Manager:- The manager is a part of operating system of the host computer & all physical input & output

   DATA BASE MANAGEMENT (DBA) Centralized control of the database is achieved by a person or group of persons under the super version of a high level administration this person or group is refer to as the data base administration. DBA is responsible for creating, modified & maintaining, its 3 level. The DBA is the causation of the data & controls database structure. The DBA administrates the 3 level of database & in consultation with the overall user community setup the definition of conceptual level of the database The DBA further specifies the user view of the various users:- DBA is responsible for definition & implantation of the internal level including the storage structure & excess method to be used for the optimum performance of the DBMS. DBA is responsible for granting  permission to the users of the database & store the profile of each user in the database. This profile describe the permissible act of a user on that question of the database accessible t

   3 Level Architecture:- The architecture of DBMS is divided into three level:- The view at each of these is describe by a schema. A schema is an outline or a plane that describe the records & relationship existing in the view. External view (view A, view B, view C):-                                                           The external view is the highest level of data base abstraction. Where only those question of the data base of console to a user or application program are included any number of user views may exist for a given global or conceptual view.    2. Conceptual view:-                                               One conceptual view represent the entire database. This view is define by the conceptual schema each describe all the records & relationship included in the conceptual view in the database. There is only one conceptual view per database. Data at this level is in a format independent of its physical it also includes features that specified the checks to

   D.B.M.S Full form of D.B.M.S (Data Base Management System). it is use to organized data in any organized  persistent collection of data of an organization. The database of an enterprise.  File Base System:-                                           File based system are early used in any organization. The manual filing system work well when the number of items to be stored is small.  Limitation of file base system:- Duplication of data In consistence data Data  dependence Fixed queries Data:- Data is row fact in which after processing we get meaning full information. Advantages of D.B.M.S:- Improved Integrity Reduction of  redundancy Sharing of data Data  independence Efficient data