Assignment Overview
"In this assignment you will write a program that allows a database user to insert, delete, modify, and query their data on basic tables (i.e., no table joins). It is assumed that the database and table structures (i.e., their metadata) are ready, which should have been completed in the frst assignment."
Implementation
This database metadata management application is implemented using Python 3, and allows for the creation, deletion, and altering of databases and tables. Databases are created as subdirectories within the `databases` directory in the root of the repository. Within those directories, tables are created with the format:
```
attribute_name1 attribute_type1 | attribute_name2 attribute_type2
value1 | value2
```
Attributes that are selected from tables are loaded into two dimensional lists and parsed to output any associated values, or alter attributes.
Usage
The program can be run with: `python3 app.py`
The following commands can be used:
```
CREATE DATABASE <database name;
CREATE TABLE <table name(<attributes);
USE <database name;
INSERT into <table name values(<values);
UPDATE <table name SET <attribute = <value WHERE <attribute = <value;
SELECT <attribute, * FROM <table name;
DELETE from <table name WHERE <attribute = <value;
DROP DATABASE <database name;
DROP TABLE <table name;
ALTER <table name ADD <attribute_name <attribute_type;
.EXIT
--<Comment
```
Sample Input
```
CREATE DATABASE CS457_PA2;
USE CS457_PA2;
CREATE TABLE Product (pid int, name varchar(20), price float);
--Insert new data (20 points)
insert into Product values(1, 'Gizmo', 19.99);
insert into Product values(2, 'PowerGizmo', 29.99);
insert into Product values(3, 'SingleTouch', 149.99);
insert into Product values(4, 'MultiTouch', 199.99);
insert into Product values(5, 'SuperGizmo', 49.99);
select * from Product;
--Modify data (20 points)
update Product
set name = 'Gizmo'
where name = 'SuperGizmo';
update Product
set price = 14.99
where name = 'Gizmo';
select * from Product;
--Delete data (20 points)
delete from product
where name = 'Gizmo';
delete from product
where price 150;
select * from Product;
--Query subsets (10 points)
select name, price
from product
where pid != 2;
.exit
```
Expected output
```
-- Expected output
--
-- Database CS457_PA2 created.
-- Using database CS457_PA2.
-- Table Product created.
-- 1 new record inserted.
-- 1 new record inserted.
-- 1 new record inserted.
-- 1 new record inserted.
-- 1 new record inserted.
-- pid int|name varchar(20)|price float
-- 1|Gizmo|19.99
-- 2|PowerGizmo|29.99
-- 3|SingleTouch|149.99
-- 4|MultiTouch|199.99
-- 5|SuperGizmo|49.99
-- 1 record modified.
-- 2 records modified.
-- pid int|name varchar(20)|price float
-- 1|Gizmo|14.99
-- 2|PowerGizmo|29.99
-- 3|SingleTouch|149.99
-- 4|MultiTouch|199.99
-- 5|Gizmo|14.99
-- 2 records deleted.
-- 1 record deleted.
-- pid int|name varchar(20)|price float
-- 2|PowerGizmo|29.99
-- 3|SingleTouch|149.99
-- name varchar(20)|price float
-- SingleTouch|149.99
-- All done.
```
