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#Advanced java tutorial : #adv java JDBC :Need of JDBC?
-- The data stored in variable of the application will be vanished/cleared/removed , once the application is completed. (Execution is over)
Because these variable & application uses teh memory of RAM & RAM is a temporary memory.
--To solve this problem collect the data from the variables of the application storing in permanent storage like file & database s/w's (these allocates the memory in permanent memory called hard disk)
I/O stream
1) java appln----- files (java.io.*)
jdbc code
2)java appln-----Database s/w (java.sql.*, javax.sql.*)
(Uses JDBC Api) (oracle,mysql, sybase & etc)
Files are not good as persistence store because of following reasons:
--No security. -No query language support. -not suitable to maintain huge amount of data. -update, delete operations are difficult to handle.-merging & comparison operation are difficult.
Note:- To overcome this above problems use database s/w as persistence store.
use files as persistence store in small scale application (bcoz of their small size.)ex. mobile games, desktop application.
Use DB (database) s/w as persistence store in medium & large scale projects.
ex. Website, banking application etc...
-The place or location where data can be saved & managed permanently is called as persistence store.(files, db s/w)
-insert, delete, select, update operations performed on persistence stores are called as peristance operations.
-The logic that is used in our aplication to perform perisistance operations on persistance store is called as "persistance logic"
# Sample application:
-Read sno, sname values from keyboard .(Presentation logic)
-read marks1, marks2, marks3 values form the database.(persistence logic)
-Calcuates total & percentage.(business logic)
-generate the rank of the student.(business logic)
-insert sno, sname, total marks, percentage, rank details in database table.(Persistance logic)
- Display student details along with result. (presentation logic.)
-- the logic which provides user interface to the end user(operator of s/w -project) is called as presentation logic.
-End user uses this user interface supplied and gives the result given the appln.
-the main logic of the applicatioon that generate results through calculation is called as business/service logic.
-The logic that is used in our aplication to perform perisistance operations (insert, update, select,delete) on persistance store is called as "persistance logic"
java application uses i.o streams based persistence logic to link/talk with files.
Java appln uses JDBC/hibernate/jta etc...based peristence logic to interacct with database s/w.
Persistence operation are also called as curd/crud/scud
c- create(insert), u-update, R-read(select) d-delete
Device drivers are bridge between operating system & peripharal devices that are connected to computers.
JDBC driver is a bridge between java appln & database s/w, It converts java calls to database calls & vice-versa.
Q. All s/w technologies based application are using ODBC drivers. then why java appln looking for separate JDBC driver.
ODBC drivers are developed in C lang. utilizing the pointer concept, since java does not support the pointers. so that java appln can not use ODBC Driver but they can use JDBC drivers to interact with DB S/w.
JDBC is not a installable ------ its a s/w technology.
Q. What is JDBC?
it is a open source s/w specification given by sun microsystem having set of rules & guidelines to develop JDBC drivers for various database s/w's.
Q. What is ODBC ?
(Open Database connectivity) its an open s/w specification given by xopen company having set of rules & guidelines to develop ODBC Drivers for database s/w's.
Q. what is the difference between programming lang & s/w tech.?
progaming lang is a direct s/w with minimum facilities to develop appliicactoin direcly. Ex. c, c++, java
S/w technolgoy is a s/w specifications having set of rules & guidelines to develop softwares. We can not work with s/w technology directly. but we can work with s/w given by/develped based on s.w technolgies.
Ex. JDBC, servlets, JSP etc....
Writing JDBC code in our appln is nothing but working with JDBC Driver.
Q. What is the difference between open s/w specification & proprietary s.w specification.
Open s/w specification is free to be used by vendor company to develop s/ws that means any vendor company can develop the s/w based on open specification.
ex. JDBC, ODBC, Servlets etc
proprietary s/w specification is specific to one company & only that vendor company is allowed to develop the s/w based on this specification.
ex. .NET specification.
- in JDBC there is no abstract classes. it contains only interfaces & concrete classes.
-s.w spefication supplies API representation rules & guidelines.
Here rules are the methods developed /declared in abstract classes.