Description

Dr. Alireza Manashty
In this assignment, you are going to practice learning Python programming by creating a simple DBMS in Python. The goal is for you to understand how Python, as a programming language, can be used to provide an interface for a higher-level query language like SQL. You will learn about string manipulation techniques and creating classes in Python.
For this assignment, (1)submit a .ipynb file and (2)an exported .html file, along with (3)required files, that includes all the sections below, clearly identified and (4) documented using Markdown cells, written in a Jupyter notebook. Everything should be rigorously tested and the test outputs should be present in the file when creating the output or saving the file. Make sure you identify each heading with Heading 1 in markdown (e.g., ‘# Assignment 1.1, 1.2, etc.’).
1. Implement the following function in Python which receives a simple SQLstatement str as string and returns the name of the table after the from keyword.
def findTable(str)
For example, findTable(“select * from customers”) will return “customers”
2. Implement the following function which returns the attributes of a selectstatement which are located between select and from statement.
def getAttributes(str)
For example,
getAttributes(“select * from customers”) will return “*” and getAttributes(“select name, customerID from customers”) will return the following list of attributes: [“name”, “customerID”]
3. Define a class in Python named Attribute with two string fields: name and type (default to “string”).
4. Define a class in Python named Table which contains a list of “Attributes” named attributes and a list of lists called rows. Table also contains a name attribute.
5. Create a class named “Database” which can contain a list of Tables calledtables.
6. Implement Database.read(tablename, filename) that reads a CSV file provided in the <filename> which creates a table named <tablename> and adds it to its tables list. Assume that CSV file columns contain only “string” data types and has a header row containing the attribute heads.
For example:
db = Database()
db.read(‘People’,“file.csv”)
The file.csv contents could look like the following:
ID,Name,Age
1,John,20
2,Mary,19
3,Alex,20
7. Implement Database.select(query, count) that receives a simple select statement as <query> and returns the results as a formatted table up to <count> rows. Use findTable(str) and getAttributes(str) which you implemented earlier.
For example:
db = Database()
db.read(‘People’,“file.csv”) db.select(‘select * from people’)
ID Name Age
1 John 20
2 Mary 19 3 Alex 20
db.select(‘select name from people’)
Name
John
Mary Alex
Notes:
For this assignment, consider inputs, select statements, and the formatting of the CSV files to be simple and similar to examples provided.
You should implement most of the functionality as member functions inside of each class. Make sure your classes have necessary member functions, attributes, and constructors to accomplish these tasks.
You are not allowed to use any third-party libraries or tools (such as NumPy, pandas, etc.), unless absolutely necessary. For example, the CSV file should be read line by line using basic Python, and not using pandas.
You will require string manipulation functions. Learn about them and apply them as necessary. Stackoverflow and other online references could help you achieve basic tasks if you found yourself struggling.
Do it yourself Good luck!