DBMS● BY THIS YOU CAN EASLY LEARN THEDBMS.● NOTES BY – MAYANK TIWARI
DATABASE MANAGEMNETSYSTEM(DBMS)1. INTRODUCTION OF DBMS2. PROPERTIES OF DBMS3. BENIFITS OF DBMS4. TYPES OF DBMS5. E/R DIAGRAM6. ENTITIES IN ER DIAGRAM7. RELATIONSHIP IN ER DIAGRAM8. DBMS & RDBMS KEY DIFFERENCES
INTRODUCTION OF DBMS● WHAT IS DBMS :-DBMS is data basemanagement system. it is use for managingthe DATAINFORMATION.In 1960 CHARLS SACHMENS make firstDBMS name ids (integrated data store)Stands for "Database ManagementSystem." In short, a DBMS is a databaseprogram.
Technically speaking, it is a software system that uses astandard method of cataloging, retrieving, and runningqueries on data. The DBMS manages incoming data,organizes it, and provides ways for the data to bemodified or extracted by users or other programs.Some DBMS examples include MySQL, PostgreSQL, MicrosoftAccess, SQL Server, FileMaker, Oracle, RDBMS, dBASE,Clipper, and FoxPro. Since there are so many databasemanagement systems available, it is important for there to be away for them to communicate with each other. For this reason,most database software comes with an Open DatabaseConnectivity (ODBC) driver that allows the database to integratewith other databases. For example, common SQL statementssuch as SELECT and INSERT are translated from a programsproprietary syntax into a syntax other databases can understand
● WHY USE DBMS :-DataBase ManagementSystem (DBMS) is a software package itallows data to be effectively stored, retrievedand manipulated And the data stored in aDBMS packege can be accessed by multipleusers and by multiple application programslike (SQL Server, Oracle, Ms-Access) .
PROPERTIES OF DBMS1. Data Definition2. Data Manipulation3. Data Security & Integrity4. Data Recovery & Concurrency5. Data Dictionary6. Performance7. Defining Database8. Constructing Database9. Manipulating Database
BENIFITES OF DBMS1. Controlling Redundancy:2. Integrity can be enforced:3. Inconsistency can be avoided :4. Data can be shared:5. Standards can be enforced :6. Restricting unauthorized access:7. Solving Enterprise Requirement than Individual Requirement:8. Providing Backup and Recovery:9. Cost of developing and maintaining system is lower:10. Data Model can be developed :11. Concurrency Control :NOTE – FROM http://ecomputernotes.com/
TYPES OF DBMSDATABASE ARE OF FOUR TYPES :-1. NAVIGATIONAL OR HIERARCHICAL :-Data storing inthis DBMS is based on parent child relationship like classes.Ex.- windows XP.2. NETWORK DBMS :-In this DBMS data storing based onmany to many relationship. It is a complex database.Ex. - RDM server
3. RDBMS :-It store the DATAINFORMATION in the form oftable. All the data relationship is in tabular foam. In this we usepredefined DATATYPES for storing our DATAVALUES.Most popular & useable DBMS. & easy to use & understand.4. OBJECT ORIANTED RELATIONAL DATABASEMANAGEMENT SYSTEM(OORDBMS) :-It store theDATAINFORMATION in the foam of object. Objects haveattributes & methods. So it is also complicated. We use it forsome definet purpose.
E/R DIAGRAMAn Entity Relationship Diagram (ERD) is a visualrepresentation of different data using conventions thatdescribe how these data are related to each other. Forexample, the elements writer, novel, and consumermay be described using ER diagrams this way:ER diagram with basic objects:
In the diagram, the elements inside rectangles arecalled entities while the items inside diamonds denotethe relationships between entities. This ER diagramtutorial for beginners covers most things related to ERdiagram, for quick navigation use the links below.To make ER diagram we use the below symboles :-Elements of ER diagram :-
ENTITIES IN ER DIAGRAMAn entity can be a person, place, event, orobject that is relevant to a given system. Forexample, a school system may includestudents, teachers, major courses, subjects,fees, and other items. Entities arerepresented in ER diagrams by a rectangleand named using singular nouns.
RELATIONSHIP IN ERDIAGRAM● A relationship describes how entitiesinteract. For example, the entity “carpenter”may be related to the entity “table” by therelationship “builds” or “makes”.Relationships are represented by diamondshapes and are labeled using verbs.
KEYS IN DBMS● A key is an attribute (also known as columnor field) or a combination of attribute that isused to identify records. Sometimes wemight have to retrieve data from more thanone table, in those cases we require to jointables with the help of keys. The purposeof the key is to bind data together acrosstables without repeating all of the data inevery table.
DBMS & RDBMS KEYDIFFERENCES1. Main difference between the DBMS and RDBMS is we canestablish the relation between the tables in RDBMS.in case ofDBMS we cannot establish relation between tables.2. Another difference between dbms and rdbms is that RDBMSfollows relational data model where as dbms can follow evennetwork, hierarchical or other data model.3. The relational model is based on set theory ,its accuracy andusefulness have a basis in mathematics.4. In RDBMS, if we open the Database, the whole tables can beaccessable, where in DBMS, we need to open each and everytable whenever we want to use.5. RDBMS allows the data to be queried based on any column inany table not need to create an index or keys in order to querydata.So, relational data is easier to query than hierarchical,CODASYL, or some other model.
Teacher table(containing teachers name) is related with studenttable(containing student name) by the relation that Student canteach by Teacher.Here Student and teacher are table and Teaches by is therelation between them.This database is introduced by E. F. Codd. Most popularcommercial and open source databases currently in use arebased on the relational model.