Database Connectivity:
#Step1 import the sqlite
import
sqlite3 as s
#step2:
conn=s.connect('escdb.db')
print("Database
opened successfully")
Steps:
To
create
Persistanece: OOP’s
Class,object,
abstraction,encapsulation,inheritance,polymorphsm…persistence
Files…
Java,
python,…
To
store the data we can use:
Files
or database.
File: A file can data in the secondary memory
ex: hard disk. It can store text format or binary format. Data is stored
unformatted
Database:
collection of data. We can store the data in the database
Once
the data is stored in a database, we need to perform operations on data.
Operations:
Modification
to the existing data
Deletion
for unnecessary data
Reading
/Retrieving the data from the database
These
operations is called Database Management systems (DMBS)
Dbms=db+application(Java/Python/…)
Advantages of DBMS:
1. Storing and
retrieving the data is so simple to compared to files by
Using SQL(Structured Query
Language) Commands we can perform.
2.
We can not store the huge amount of data in the files
whereas we can store in Database
3.
Relationship is not possible to maintain in the files
4.
Multiple users can retrieve or access the database
simultaneously.
5.
If any changes are done, we can not rollback to the
files
6. Files are very weak
security. Whereas DBMS Offers good security.
Example
2:
#creating
table
#import
the sqlite
import
sqlite3 as s
conn=s.connect('escdb.db')
print("Database
opened successfully")
conn.execute('''CREATE
TABLE APSSDC(
ID
INT PRIMARY KEY NOT NULL,
NAME
TEXT NOT NULL,
AGE
INT NOT NULL,
ADDRESS
CHAR(50),
SALARY
REAL);''')
print("Table
created successfully")
conn.close()
"""
Database
opened successfully
Table
created successfully
"""
Steps to connect to SQLite:
1. Import the module.
Ex: import sqlite3.
2.
Use connect() method of a sqlite3 module and pass the
actual parameter with database name as
an parameter/argument. Ex: conn=s.connect('escdb.db')
3. Perform sql
operations: Example: conn.execute(‘’’……’’’’)
Import sqlite3: we can use all the classes,method of sqlite3 module
Sqlite3.connect(): We can create connection to the SQLite Database.
If
you want to use any database, first we should be installed in our system then
only we can create database.
We
have so many database in the market:
1. Oracle
2.
GadFly
3.
mSQL
4.
MySQL
5.
PostgreSQL
6.
Microsoft SQL Server 2000
7. IBM DB2
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