4. DBMS-
A DBMS IS A SYSTEM SOFTWARE FOR CREATING AND MANAGING
DATABASES.THE DBMS PROVIDES USERS AND PROGRAMMERS
WITH A SYSTEMATIC WAY TO CREATE,RETRIEVE,UPDATE AND
MANAGE DATA.
OR
IN OTHER WORDS,DATABASE MANAGEMENT SYSTEM IS A
SOFTWARE PACKAHE THAT ALLOW DATA TO BE EFFECTIVELY
STORED ,RETRIEVED AND MANIPULATED.THE DATA CONTAINED
IN A DBMS PACKAGE CAN BE ACCESSED BY MULTIAPPLICATION
PROGRAM AND USERS.
THE VARIOUS DBMS PACKAGES SUCH AS:
MYSQL
ORACLE
SQL SERVER
MS ACCESS
FOXPRO
HADOOP.
5. TYPES OF DBMS:-
MAINLY FIVE TYPES-
1.HIERARCHICAL DBMS
2.NETWORK DBMS
3.RELATIONAL DBMS
4.DISTRIBUTED DBMS
5.OBJECT-ORIENTED DBMS
6. 1.HIERARCHICAL DBMS:-
IT OPERATES ON THE PARENT CHILD TREE-LIKE MODEL.THESE NORMALLY
1:M RELATIONSHIP AND ARE GOOD FOR STORING DATA WITH ITEMS DESCRIBING
ATTRIBUTES ,FEATURES AND SO ON.
IT IS VERY FAST ANDS SIMPLE
IT CAN BE USED TO STORE A DATABASE OF SONGS,RECIPES,MODELS OF PHONES
AND ANYTHING THJAT CAN BE STORED IN A NESTED FORMAT.
ADVANTAGES:
HIERARCHICAL DATABASE CAN BE ACCESSED AND UPDATED RAPIDLY BEZ
IN THIS MODEL STRUCTURE IS LIKE AS A TREEE AND THE RELATIONSHIPS
BETWEEN THEM RECORDS ARE DEFINE IN ADVANCED.
DISADVANTAGES-
THIS TYPE OF DATABASE STRUCTURE IS THAT EACH CHILD IN THE TREE
HAVE INLY ONE PARENT,AND RELATIONSHIPS OR LINKAGES BETWEEN
CHILDREN ARE NOT PERMITTED.IT IT CAN ADDING A NEW A NEW FIELD
RECORD REQUIRES THAST THE ENTIRE DATABASE BE REDEFINED.
7. 2.NETWORK DBMS:-
A NETWORK DATABASES ARE MAINLY USED ON A LARGE
DIGITAL COMPUTERS.NETWORK DATABASES ARE SIMILAR TO
HIOERARCHICAL DATABASES BY ALSO HAVING A
HIERARCHICAL STRUCURE.
IN THIS ,CHILDREN ARE CALLED MEMBERS AND PARENTS ARE
CALLED OCCUPIER.THE DIFFERENCE BETWEEN EACH CHILD OR
MEMBER CAN HAVE MORE THAN ONE PARENT.
THE MAJOR DIFFERENCE HERE IS THAT THE TREE STRUCTURE IN
THE NETWORK MODELS CAN HAVE A MANY PARENT TO MANY
CHILD RELATIONAL MODEL.
8. 3.RELATIONAL DBMS:-
RDBMS ARE THE MOST WIDELY USED DATABASE
MANAGEMENT SYSTEM TODAY.THEY ARE RELATIVELY EAST TO
USE.
IN A RELATIONAL DATABASE,DATA IS ORGANISED IN THE
FORM OF ROWS AND COLUMNS.THAT MEANS TABLE.THE
TABLE ARE REFERRED TO AS RELATIONS IN RELATIONAL
DATAMODELROWS OF THE TABLE ARE REFERRED TO AS
“TUPLES” AND COLUMNS OF THE TABLES ARE FERERRED TO AS
“ATTREIBUTES”.
IT WORKS ON TABLE,EACH TABLE HAS A KEY FIELD THAT
UNIQUELY INDICATED EACH ROW & THAT KEYFIELDS CAN BE
USED TO CONNECT ONE TABLE TO ANOTHER.
EX-ORACLE,SQL SERVER,IBM,DB2….
9. DATA MODEL:-
A DATA MODEL IS A DESCRIPTION OF THE ORGANISATION
OF A DATABASE.DATA MODELLING IS USED FOR
REPRESENTING ENTITIES AND THEIR RELATIONSHIPS IN A
DATABASE.A DATA MODEL NOT ONLY DESCRIBES THE
STRUCTURE OF THE DATA BUT ALSO DEFINES A SET OF
OPERATIONS THAT CAN BE PERFORMED ON THE DATA.
THEY CAN BE-
HIERARCHICAL MODEL
NETWORK MODEL
RELATIONAL MODEL
10. 1.HIERARCHICAL MODEL-
IT MAKES STRUCTURE LIKE TREE WHICH DIVIDED INTO ROOT,PARENT,AND CHILD.
THIS WAS BROUGHT IN 1970 BY INFORMATION MANAGEMENT SYSTEM OF IBM.
IT REPRESENTS 1:M RELATIONSHIP.
2.NETWORK MODEL-
IT HAS BEEN MADE IN 1971 ON THE CONFERENCE ON DATASYSTEM
LANGUAGES.
IT SUPPORYTS THE CONCEPT OF MULTIPARENT.
IT SHOWS 1:1 AND 1:M RELATIONSHIP.
IN THIS MODEL,WE CAN ACCESS ON ANY END AND FROM ANY END.
11. 3.RELATIONAL MODEL-
THIS MODEL HAS BEEN DEVELOPED BY E.F. CODD.
IN THIS ,WE CAN DEFINE THE STRUCTURE OF DATA AS
AS STORE AND RETRIEVE.
EVERY COLUMN HAS A UNIQUE NAME AS WELL AS ROW..
IN THIS,WE CAN JOIN TWO TABLES BY THE HELP OF JOIN
OPERATION BUT
COLUMN VALUES ARE OF THE SAME KIND.
