CS3223 Project (Database Systems Implementation)

AY2020/2021 Semester 2, School of Computing, National University of Singapore

Team members :

• Erin May Gunawan
• Florencia Martina
• Quek Wei Ping

Project Summary

This is an implementation of a simple SPJ (Select-Project-Join) query engine to illustrate query processing in a modern relational database management system. The link to our full report can be found here.

Implemented Features

1. Block Nested Loop Join (See BlockNestedLoopJoin.java)

2. Sort Merge Join based on Sort (See SortMergeJoin.java)

3. Distinct based on Sort (See Distinct.java)

4. Groupby based on Sort (See GroupBy.java)

5. Orderby based on Sort (See OrderBy.java)

6. Identified and fixed the following bugs/limitations in the SPJ engine given:

• If the table's tuple size is bigger than the buffer size, SPJ goes to infinity loop.
• If the query does not involve join, the SPJ does not require the user to input the number of buffers.
• If a join query involves more than one join condition on two same tables, the number of tuples is higher than expected.

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