Mini-SQL-Engine

In this assignment, we are supposed to write a mini?sql engine which will run a subset of SQL Queries using ?command line interface? Programming Language : Python Dataset:

1. CSV files for tables. a. If a file is : ?File1.csv ?, the table name would be File1.
   b. There will be no tab ?separation or space ?separation, so you are not required t e handle it but you have to make sure to take care of both csv file type cases: the one where values are in double quotes and the one where values are without quotes.
2. All the elements in files would be ?only ?INTEGERS??.
3. A file named: ?metadata.txt ?(note the extension) would be given to you which will have the following structure for each table: <begin_table> <table_name> .... <end_table>

Types of Queries:

1. Select all records: Example Query: Select * from table_name;

2. Aggregate functions: Simple aggregate functions on a single column namely - ?Sum, average, max and min?.
   ?Example Query: Select max(col1) from table1;

3. Project Columns (could be any number of columns) from one or more tables:
   Example Query: Select col1, col2 from table_name;

4. Select/project with distinct (for only one attribute) from one table.
   Example Query: Select distinct(col1) from table_name;

5. Select with where from one or more tables : a. In the where queries, there would be a maximum of one AND/OR operator with no NOT operators. b. Relational operators that are to be handled in the assignment, the operators include "<, >, <=, >=, =".
   Example Query: Select col1,col2 from table1,table2 where col1=10 AND col2=20;

6. Projection of one or more(including all the columns) from two tables with one join condition : a. NO REPETITION OF COLUMNS – THE JOINING COLUMN SHOULD BE PRINTED ONLY ONCE.
   Example Query1: Select * from table1, table2 where table1.col1=table2.col2;
   Example Query2: Select col1,col2 from table1,table2 where table1.col1=table2.col2 AND table2.col2>=10.

Input Format:

1. For C++ it will be – ./a.out “select * from table_name where condition”
2. For Python, it will be – python RollNumber.py “select * from table_name where condition”

Output format: <Table1.column1, Table1.column2....TableN.columnM> Row1 Row2 ....... RowN

Steps to run

1.run as ---->> python 2019900004.py "sql_query_here"