SUSTech-CS307-2025-Spring-Project_2

Before you clone

Notice that PLAGIARISM WILL BE PUNISHED SEVERELY in SUSTech Computer Science and Engineering Department.

Quick Start

• You can find the original framework of this project at https://github.com/CS307-Database/engine-project
• Run the engine in DBEntry.java.
• sql_command.md provides series of sql command examples.

Features

• Support all basic operations. See Project_2_Database_Design.pdf
• Support aggregation functions.
• Support GROUP BY, ORDER BY.
• Support Nested Loop Join for equi-joins.
• Support IN, NOT IN
• Support SubSelect for IN in single Column situation. See example below.

select * from t where t.id in (select jointemp.id from jointemp)

• This project supports creating B+ trees index for SELECT,DELETE, holding the trees dynamically. However, since it's only InMemory, the trees will disappear as long as you exit the program.
• This project does not support EXISTS,'generate different query plans for different SQL statements',ALTER.
• This project does not support creating index InPhysical (save to Json), however the engine has provided a model class, you can complete this simple task yourself.

Known Issues

• After dropping a table, you should manually exit the program to flush some unknown class within the engine. Though you can drop it successfully, the ColumnMeta will still stay in memory.