SQL-Engine

• Mini-SQL engine in Python which will run a subset of SQL Queries using command line interface.

• Dataset

  • all elements in the fields would be integers only
  • file is named File1.csv, the database table name would be File1
  • metadat.txt file will be given for schema of corresponding database tables

    <begin_table>
    <table_name>
    <attribute1>
    ....
    <attributeN>
    <end_table>
    

• Queries

  • Select all records: SELECT * FROM table_name;
  • Aggregate functions: sum, average, min, max SELECT MAX(col) FROM table_name;
  • Project coloumns: SELECT col FROM table_name;
  • Project with distinct: SELECT DISTINCT col FROM table_name;
  • Select from one or more tables: SELECT col1, col2 FROM table1, table2 WHERE col1=10 AND col2=20;
  • Projection from one or more from two tables with one join condition:

  a. SELECT * FROM table1, table2 WHERE table1.col1=table2.col2;
  b. SELECT col1, col2 FROM table1, table2 WHERE table1.col1=table2.col2; 
  

  • Basic Error Handling is done

• Execute

  • run SQL-Engine from python file python sql_engine.py <query>
  • run SQL-Engine from bash script bash run.sh