HW2 Simple DBMS feature extend (Basic) Solution

1 Overview




In this homework, you are asked to implement new features of the simpleDBMS​,this project is under Apache 2.0 License, the detail of this project refer to its ​GitHub Repo​.​The expected result of this homework is to support the below query format




select { ​field​}from table ​[offset <​offset_num​​][​limit <​limit_num​​]




1.1 Format description




field ​means the attributes in the table, i.e.: id, name, email, age




offset_num ​&​limit_num​are numeric input, they should always be unsigned int [ ]​means optional argument







Prerequisite



Installation of simpleDBMS



Git



C programming language



You can also use C++ to implement this project, but it needs to pass all the system tests and unit test without any modification on test code, as well
Understanding of simpleDBMS



Tasks



Primary Key



Limit argument



Offset argument



Projection (field select)



3.1 Primary Key




Implement ​user.id​as the primary key in the Table




Example:







Table content:




ID
Name
email
age








1
user1
user1@example.com
20








2
user2
user2@example.com
21








If we execute the following command, the table will remain the same, because of the primary key restriction




db insert 2 user3 ​user3@example.com​22







3.2 Limit argument




Implement limit argument to restrict the number of output







Example:







Table content:




ID
Name
email
age








1
user1
user1@example.com
20








2
user2
user2@example.com
21








3
user3
user3@example.com
22








4
user4
user4@example.com
23








If we execute the following command db select limit 2




The result will be as below shows because we restrict it only output 2 records




(1, user1, ​user1@example.com​,20)







(2, user2, user2@example.com​,​21)







3.3 Offset argument




Implement offset argument to add offset for the query result







Example:







Table content:




ID
Name
email
age








1
user1
user1@example.com
20








2
user2
user2@example.com
21








3
user3
user3@example.com
22








4
user4
user4@example.com
23








If we execute the following command db select offset 2




The result will be as below shows because we shift the output with offset 2




(3, user3, ​user3@example.com​,22)







(4, user4, user2@example.com​,​24)













3.4 Projection (field selection)




Implement projection(field selection) in select query







Example:







Table content:




ID
Name
email
age








1
user1
user1@example.com
20








2
user2
user2@example.com
21








3
user3
user3@example.com
22








4
user4
user4@example.com
23











If we execute the following command db select id, name from table




The result will be as below shows




(1, user1)




(2, user2)




(3, user3)




(4, user4)







4 Testing




This project is implemented with two kinds of tests, the different type of tests focuses on a different aspect.




4.1 Unit tests




The unit tests are focus on the function level specification, it will check the input and output of the function.

Use the following command to execute unit tests




$ make check







4.2 System tests (For above requirement)




The system tests focus on system level behavior, and these tests are also used to test the new features you need to implement




Use the following command to execute system tests




​$python test/system/system_test.py ./shell [test_case [test_case ...]]



Execute this command in the root folder of this project



By default, if no test_cases are given, it will run all test cases, otherwise, it will execute all specified test cases.
To see the list of test cases, please check ​test/system/testcases folder



$ python test/system/system_test.py [-h]



Show the usage of system test



You can check the difference of your test output with the expected answer by comparing two files in these two paths “test/system/output/<test_case/<output file” “test/system/answer/<test_case/<answer_file”



Hint: 1) ​diff ​command can show the difference of two files



2) Install ​vim ​and using ​vimdiff ​provide a better looking



Requirements:



Pass unit tests



Pass provided system tests



You should at least 5 commits to your own repository



Upload a zip file to New E3



Makefile



The original project already contains a Makefile, your final submission should also be able to compile the shell using Makefile, and the compiled binary should be ​shell​as we provided,​otherwise you will get 0 score



Passing unit tests and system tests only means that your program reaches the basic requirements. There are some hidden tests we do not provide and we will test them on your submission. Therefore, make sure your program works well on query with different combinations of features(field selection + offset + limit).




6 Submission




6.1 E3




Compress your source code into one single zip file named `<student_ID.zip` (like 0756000.zip), and upload to New E3



6.2 GitLab




Create an project named ​<student_id_hw2​in the Group DBMS_2019/<student_id



The <student_id should be replaced with your own student_id, such as ​0756000_hw2​in group DBMS_2019/0756000



6.3 Deadline




You are required to hand in your homework before ​2019/04/21 23:59



Late submission is not allowed






7 Disscussion Forum




HW2 discussion <HackMD







Plagiarism is not allowed, you will get 0 points when we found that happened.