(i) char (Character)
(ii) varchar
(iii) dec (Decimal)
(iv) numeric
(v) int (Integer)
(vi) smallint
(vii) float
(viii) real
(ix) double

(i) A data model describes how the data can be represented and accessed from a software after complete implementation
(ii) It is a simple abstraction of complex real world data gathering environment.
(iii) The main purpose of data model is to give an idea as how the final system or software will look like after development is completed.

(i) RDBMS
(ii) DBMS
(iii) RDBMS
(iv) DBMS

Program:
For example, to plot x versus y, you can issue the command:
import matplotlib. pyplot as plt
pIt.plot([1,2,3,4], [1,4,9,16])
plt.show ( )
Output:

(i) DISTINCT
(ii) WHERE
(iii) GROUP BY
(iv) ORDER BY.
(v) HAVING

Step 1: Import sqlite3
Step 2: Create a connection using connect o method and pass the name of the database File
Step 3: Set the cursor object cursor = connection. cursor ( )

Search	To search an item in a data structure using linear and binary search.
Sort	To sort items in a certain order using the methods such as bubble sort, insertion sort, selection sort, etc.
Insert	To insert an item (s) in a data structure.
Update	To update an existing item (s) in a data structure.
Delete	To delete an existing item (s) in a data structure.

Integer Data can be decimal, octal or hexadecimal. Octal integer use O (both upper and lower case) to denote octal digits and hexadecimal integer use OX (both upper and lower case) and L (only upper case) to denote long integer.

(i) Data abstraction is supported by defining an abstract data type (ADT) which is a collection of constructors and selectors.
(ii) Constructors create an object, bundling together different pieces of information, while selectors extract individual pieces of information from the object.

Program: Display the records in descending order using python script
import mysqldb
db = mysqldb.connect ("local host", "user", "123", "organization")
cursor = db.cursor()
cursor.execute ("SELECT *FROM Employee ORDER BY Name DESC")
result = cursor.fetchall()
for row in results:
ENO = row[0], EmpName = row[1], EmpDept = row[2]
print ENO, EmpName, EmpDept
db.close()

(i) SQLite is a simple relational database system, which saves its data in regular data files or even in the internal memory of the computer.
(ii) It is designed to be embedded in applications, instead of using a separate database server program such as MySQL or Oracle.
Advantages:
SQLite is fast, rigorously tested, and flexible, making it easier to work.
Python has a native library for SQLite.

Program: To read a csv file with comma (,)
#importing csv
import csv
#opening the csv file which is in different location with read mode
with open('c:\\Pyprg\ \sample1.csv', 'r') as F:
#other way to open the file is
f=('C:\\pyprg\\sample1.csv', 'r')
reader = csv.reader(F))
#printing each line of the Data row by row.
print (row)
F. close( )
Output:
['SNO','NAME', 'CITY']
['12101', 'RAM', 'CHENNAI']
['12102', 'LAVANYA' "TIRUCHY']
['12103', 'LAKSHMAN', 'MADURAI']

(i) The DISTINCT keyword is used along with the SELECT command to eliminate duplicate rows in the table. This helps to eliminate redundant data.

(ii) For Example: SELECT DISTINCT Place FROM Student;
    Will display the following data as follows:
    Place
    Chennai
    Banglore
    Delhi

 

ALTER TABLE <table-name> ADD <column- name><data type><size>;
Example: ALTER TABLE Student MODIFY Address char (25)

 

 

S.No	Concrete data type	Abstract data type
(i)	Concrete Data Types or structures (CDT's) are direct implementations of a relatively simple concept	Abstract Data Types (ADT's) offer a high level view (and use) of a concept independent of its implementation.
(ii)	A concrete data type is a data type whose representation is known.	Abstract data type the representation of a data type is unknown.

 

The various processing skills of SQL are:
(i) Data Definition Language (DDL): The SQL DDL provides commands for defining relation schemas (structure), deleting relations, creating indexes and modifying relation schemas.
(ii) Data Manipulation Language (DML): The SQL DML includes commands to insert, delete, and modify tuples in the database.
(iii) Embedded Data Manipulation Language: The embedded form of SQL is used in high level programming languages.
(iv) View Definition: The SQL also includes commands for defining views of tables.
(v) Authorization: The SQL includes commands for access rights to relations and views of tables.
(vi) Integrity: The SQL provides forms for integrity checking using condition.
(vii) Transaction control: The SQL includes commands for file transactions and control over transaction processing.

Program:
import matplotlib.pyplot as plt
sizes = [89, 80, 90, 100, 75]
labels = ["Tamil", "English", "Maths", "Science", "Social"]
plt.pie (sizes, labels = labels, autopct = "%.2f")
plt.axes( ).set aspect ("equal")
pIt.show ( )

import csv
with open ('c\\pyprg\\ch13\\ dynamicfile.csv', 'w') as f:
w = csv.writer(f)
ans= 'y'
while (ans=='y'):
name=input("Name?:")
date=input("Date of birth:")
Place=input ("Place:")
w.writerow([name, date, place])
ans=input("Do you want to enter more y/n?:")
F=open('c:\\pyprg\\ch13\\dynamicfile.csv",r')
reader=csv.reader(F)
for row in reader:
print (row)
F.close()

import csv
csv.register_dialect('myDialect', delimiter = ',',skipinitialspace = True)
F=open('c:\\pyprg\\sample2.csv', 'r')
reader = csv.reader(F, dialect = 'myDialect')
for row in reader:
print(row)
F.close( )

(i) The basic idea of data abstraction is to structure programs so that they operate on abstract data. That is, our programs should use data in such a way, as to make as few assumptions about the data as possible.
(li) At the same time, a concrete data representation is defined as an independent part of the program.
(iii) Any program consist of two parts. The two parts of a program are, the part that operates on abstract data and the part that defines a concrete representation, is connected by a small set of functions that implement abstract data in terms of the concrete representation.
(iv) To illustrate this technique, let us consider an example to design a set of functions for manipulating rational numbers.
(v) Example: A rational number is a ratio of integers, and rational numbers constitute an important sub-class of real numbers. A rational number such as 8/3 or 19/23 is typically written as : < numerator > /< denominator >
(vi) where both the < numerator > and <denominator> are placeholders for integer values. Both parts are needed to exactly characterize the value of the rational number. Actually dividing integers produces a float approximation, losing the exact precision of integers.
(vii) However, you can create an exact representation for rational numbers by combining together the numerator and denominator.
(viii) As we know from using functional abstractions, we can start programming productively before you have an implementation of some parts of our program.
(ix) Let us begin by assuming that you already have a way of constructing a rational number from a numerator and a denominator. You also assume that, given a rational number, you have a way of selecting its numerator and its denominator component.

(i) Home Button \(\rightarrow \) The Home Button will help one to begun navigating the chart. If you ever want to return back to the original view, you can click on this.
(ii) Forward/Back buttons \(\rightarrow \) These buttons can be used like the Forward and Back buttons in browser. Click these to move back to the previous point you were at, or forward again.
(iii) Pan Axis \(\rightarrow \) This cross-looking button allows you to click it, and then click and drag graph around.
(iv) Zoom \(\rightarrow \) The Zoom button lets you click on it, then click and drag a square would like to zoom into specifically. Zooming in will require a left click and drag. Zoom out with a right click and drag.
(v) Configure Subplots\(\rightarrow \) This button allows you to configure various spacing options with figure and plot.
(vi) Save Figure \(\rightarrow \)This button will allow you to save figure in various forms

Line Chart:
(i) A Line Chart or Line Graph is a type of chart which displays information as a series of data points called 'markers' connected by straight line segments.
(ii) A Line Chart is often used to visualize a trend in data over intervals of time - a time series - thus the line is often drawn chronologically.
Example:
import matplotlib.pyplot as plt
years = [2014, 2015, 2016, 2017, 2018]
total_populations = [8939007, 8954518, 8960387, 8956741, 8943721]
plt. plot ("years, total_populations)
pit. title ("Year vs Population in India")
plt.xlabel ("Year")
pIt.ylabel ("Total Population")
plt.showt (1)
In this program,
Plt.titlet( ) \(\rightarrow\) specifies title to the graph
Plt.xlabelt) \(\rightarrow\) specifies label for X-axis
Plt.ylabel() \(\rightarrow\) specifies label for Y-axis
Output:

Bar Chart:
(i) A Bar Plot (or BarChart) is one of the most common type of plot. It shows the relationship between a numerical variable and a categorical variable
(ii) Bar chart represents categorical data with rectangular bars. Each bar has a height corresponds to the value it represents. The bars can be plotted vertically or horizontally.
(iii) It's useful when we want to compare a given numeric value on different categories. To make a bar chart with Matplotlib, we can use the plt.bar() function.
Example:
import matplotlib.pyplot as plt
# Our data
labels = ["TAMIL", "ENGLISH", "MATHS", "PHYSICS", "CHEMISTRY", "CS"]
usage = [79.8,67.3,77.8,68.4,70.2,88.5]
# Generating the y positions. 
y_positions = range (len(labels))
# Creating our bar plot
plt.bar (y_positions, usage)
plt.xticks (y_positions, labels)
plt.ylabel ("RANGE")
plt.title ("MARKS")
plt.show( )
Output:

Labels → specifies labels for the bars.
Usage → Assign values to the labels specified.
Xticks → Display the tick marks along the x - axis at the values represented. Then specify the ladel for each tick mark.
Range → Create sequence of numbers.
Pie Chart:
(i) Pie Chart is probably one of the most common type of chart. It is a circular graphic which is divided into slices to illustrate numerical proportion.
(ii) The point of a pie chart is to show the relationship of parts out of a whole. To make a Pie Chart with Matplotlib, we can use the plt.pief) function.
(iii) The autopct parameter allows us to display the percentage value using the Python string formatting.
Example:
import matplotlib.pyplot as plt
sizes = [89, 80, 90, 100, 75]
labels = ["Tamil", "English", "Maths", "Science", "Social"]
plt.pie (sizes, labels = labels, autopct = "%.2f")
plt.axes().set aspect ("equal")
plt.show( )
Output:

Program:
import mysql db
db = mysqldb.connect ("local host", "user", "123", "organization'")
cursor = db.cursor()
item table creation
database: ABC, table: Item, lcode: int, ItemName: Char
Rate: int. Record: 1008, Monitor: 15000
cursor.execute ("Create table item(icode int, item Name char (25), Rate int"));
db.close
cursor. execute ("insert into item values ("1008", 'Monitor', '15000" ));
db.commit()

Rules to be followed to format data in a CSV file:
(i) Each record (row of data) is to be located on a separate line, delimited by a line break by pressing enter key.
For example:↲
xxx,yyy↲
↲denotes enter Key to be pressed
(ii) The last record in the file mayor may not have an ending line break.
For example:
ppp, qqq↲
yyy, xxx
(iii) There may be an optional header line appearing as the first line of the file with the same format as normal record lines. The header will contain names corresponding to the fields in the file and should contain the same number of fields as the records in the rest of the file.
For example:
field_name 1, field_name 2, field_name 3↲
aaa,bbb,ccc↲
zzz, yyy, xxx CRLF(Carriage Return and Line Feed)
(iv) Within the header and each record, there may be one or more fields, separated by commas. Spaces are considered part of a field and should not be ignored. The last field in the record must not be followed by a comma.
For example:
Red, Blue
(v) Each field mayor may not be enclosed in double quotes. If fields are not enclosed with double quotes, then double quotes may not appear inside the fields
For example:
"Red","Blue","Green"↲  
Black, White, Yellow 
(vi) Fields containing line breaks (CRLF), double quotes, and commas should be enclosed in double-quotes.
For example:
Red, ",", Blue CRLF 
Red, Blue, Green
(vii) If double-quotes are used to enclose fields, then a double-quote appearing inside a field must be preceded with another double quote.
For example:
"Red, " "Blue", "Green",
White

Excel	CSV
Excel is a binary file that holds information about all the worksheets in a file, including both content and formatting	CSV format is a plain text format with a series of values separated by commas.
XLS files can only be read by applications that have been especially written to read their format, and can only be written in the same way.	CSV can be opened with any text editor in Windows like notepad, MS Excel, Open Office, etc.
Excel is a spreadsheet that saves files into its own proprietary format viz. xls or xlsx	CSV is a format for saving tabular information into a delimited text file with extension .csv
Excel consumes-more memory while importing data	Importing CSV files can be much faster, and it also consumes less memory

1. SELECT * FROM student WHERE gender = Male GROUP BY gender;
2. SELECT * FROM student WHERE Age > 18 ORDER BY DESC;

(i) SELECT * FROM Employee ORDER BY PAY DESC;
(ii) SELECT * FROM Employee WHERE ALLOWANCE
BETWEEN 5000 AND 7000;
(iii) DELETE FROM Employee WHERE DESIG='Mechanic';
(iv) ALTER TABLE employee ADD Age Varchar(50);
(v) SELECT * FROM Employee WHERE DESIG='Operator';

Types of a Data Model:
1. Hierarchical Model
2. Relational Model
3. Network Database Model
4. Entity Relationship Model
5. Object Model.
1. Hierarchical Model:
(i) Hierarchical model was developed by IBM as Information Management System. In Hierarchical model, data is represented as a simple tree like structure form.
(ii) This model represents a one-to-many relationship i.e., parent-child relationship. One child can have only one parent but one parent can have many children.
(iii) This model is mainly used in IBM Main Frame computers.

2. Rational Model:
(i) The Relational Database model was first proposed by E.F. Codd in 1970. Nowadays, it is the most widespread data model used for database applications around the world.
(ii) The basic structure of data in relational model is tables (relations). All the information's related to a particular type is stored in rows of that table.
(iii) Hence tables are also known as relations in a relational model. A relation key is an attribute which uniquely identifies a particular tuple (row in a relation (table)).

3. Network Model:
Network database model is an extended form of hierarchical data model. The difference between hierarchical and Network data model is:
(i) In hierarchical model, a child record has only one parent node,
(ii) In a Network model, a child may have many parent nodes. It represents the data in many-to-many relationships.
(iii) This model is easier and faster to access the data.

(iv) School represents the parent node
(v) Library, Office and Staff room is a child to school (parent node)
(vi) Student is a child to library, office and staff room (one to many relationship)
4. Entity Relationship Model:
(i) In this database model, relationship are created by dividing the object into entity and its characteristics into attributes.
(ii) It was developed by Chen in 1976. This model is useful in developing a conceptual design for the database. It is very simple and easy to design logical view of data. The developer can easily understand the system by looking at ER model constructed.
(iii) Rectangle represents the entities. E.g. Doctor and Patient.
(iv) Ellipse represents the attributes E.g. D-id, D-name, P-id, P-name. Attributes describes the characteristics and each entity becomes a major part of the data stored in the database. Diamond represents the relationship in ER diagrams e.g; Doctor diagnosis the Patient.

5. Object Model:
(i) Object model stores the data in the form of objects, attributes and methods, classes and Inheritance.
(ii) This model handles more complex applications, such as Geographic information System (GIS), scientific experiments, engineering design and manufacturing.
(iii) It is used in file Management System. It represents real world objects, attributes and behaviors. It provides a clear modular structure. It is easy to maintain and modify the existing code.

(iv) An example of the Object model is Shape, Circle, Rectangle and Triangle are all objects in this model.
(i) Circle has the attribute radius.
(ii) Rectangle has the attributes length and breadth.
(iii) Triangle has the attributes base and height.
(iv) The objects Circle, Rectangle and Triangle inherit from the object Shape.

The syntax of CREATE TABLE command is :
CREATE TABLE < table-name >
( < column name > < data type > [ < size > ]
( < column name > < data type> [ < size > ] ..........
);

(i) The Structured Query Language (SQL) is a standard programming language to access and manipulate databases.
(ii) SQL allows the user to create, retrieve, alter, and transfer information among databases.
(iii) It is a language designed for managing and accessing data in a Relational Data Base Management System (RDBMS).

(i) SQL -Structured Query Language
(ii) DBMS-Database Management System
(iii) RDBM - Relational Database Management System

The DISTINCT clause is helpful when there is need of avoiding the duplicate values present in any specific columns/table. When we use distinct keyword only the unique values are fetched.

Execute (sql[, parameters]) :
(i) Executes a single SQL statement. The SQL statement may be parameterized (i.e. placeholders instead of SQL literals).
(ii) The SQlite3 module supports two kinds of placeholders: question marks? ("qmark style") and named placeholders: name ("named style").

(i) A cursor in SQL and databases is a control structure to traverse over the records in a database. So it's used for the fetching of the results.
(ii) The cursor object is created by calling the cursor( ) method of connection. The cursor is used to traverse the records from the result set.

(i) Object - name = class_name ()
(ll) Object - name = class_member

If the fields of data in your CSV file contain commas, you can protect them by enclosing those data fields in double-quotes ("). The commas that are part of your data will then be kept separate from the commas which delimit the fields themselves.

A CSV is known as flat file because files in the CSV format can be imported to and exported from programs that store data in tables, such as Microsoft Excel or OpenOfficeCalc

s = [x **2 for x in range (2,11,2)]
print (s)

The built-in number objects in Python supports integers, floating point numbers and complex numbers.

(i) Line plot
(ii) Scatter plot
(iii) Histogram
(iv) Box plot
(v) Bar chart and
(vi) Pie chart

A CSV file is a human readable text file where each line has a number of fields, separated by commas or some other delimiter.

SQL	MYSQL
Structured Query Language is a language used for accessing database	MySQL is a database | accessing databases. management system, like SQL Server, Oracle, Informix,postgres,etc.
SQL is a DBMS	MySQL is a RDBMS

 

Command Description Component Insert Inserts data into a table DML Create To create tables in the database DML