HW3 Simple DBMS feature extend (Advanced) Solution

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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 three type of queries:

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

update table set {<field=<content }[where <conditions] delete from table [where <conditions]

1.1 Format description

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

offset_num &limit_numare numeric input, they should always be unsigned int conditionsmeans the search condition of the query

[ ]means optional argument

Prerequisite

Installation of simpleDBMS

TA provides a new version of simpleDBMS,which has already implemented all the requirements of hw2
To get the newest simpleDBMS, you just need to visit its GitHubpage, clone or download it.

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

Support where argument

Aggregation functions

Update query

Delete query
3.1 Where Clause

The format of where clause is like

Where<conditions

The conditionsare composed of one or more conditional statements, there exist three types of condition statements

Numeric comparison

String equality comparison

Logical operator

3.1.1 Numeric comparison

The numeric comparison should support 6 operators and with two data types

Operators:

=equal to

!=not equal to

greater

<less

=greater or equal to

<=less or equal to Data types:

Integer

Floating point number

Please use double data type in C lang to do the operation

Example:

Table content:

ID
Name
email
age

1
user1
user1@example.com
20

2
user2
user2@example.com
21

db select * from table where age=20

The select result will be the following:

(1, "user1", "user1@example.com",20)

3.1.2 String equality comparison

The string comparison should support 2 operators.

Operators:

=equal to

!=not equal to

Example:

Table content:

ID
Name
email
age

1
user1
user1@example.com
20

2
user2
user2@example.com
21

db select * from table where name=”user1”

The select result will be the following:

(1, "user1", "user1@example.com",20)

3.1.3 Logical operators

The logical operators are used to extend the conditional statement, and there are two types of operators you need to implement

Operators:

and--- Just like the general logical and operation

or--- Just like the general logical or operation

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

db select * from table where age<21 or age22

The select result will be the following: (1, "user1", "user1@example.com",20) (4, "user4", "user4@example.com",23)

3.2 Aggregation Functions

Implement the following aggregation to aggregate data

avg --- the average of an expression in a SELECT statement and satisfying the criteria specified in the WHERE clause

Using doubleto do the operations, and accurate to only the third digit after the decimal point.

count --- the number of rows in a table satisfying the criteria specified in the WHERE clause

sum --- the sum of an expression in a SELECT statement and satisfying the criteria specified in the WHERE clause

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 sum(age) from table where age20 db select avg(age) from table where age20

The result will be the following because we sum up and average age which rows are satisfied age is larger than 20.

(66)

(22.000)

Note:Where is optional in the aggregation function. If no where clause is provided, all corresponding data will be included.

3.3 Update query

Implement update statement to modify data in the table

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 update table set email="user4@example.xyz" where name="user4"

db select * from table

The select result will be the following because we update the name of user4.

(1, "user1", "user1@example.com",20)

(2, "user2", "user2@example.com",21)

(3, "user3", "user3@example.com",22)

(4, "user4", "user4@example.xyz",23)

Note:Where is optional in the update statement. If no where clause is provided, all corresponding data will be updated.

3.4 Delete query

Implement delete statement to remove data from the table

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 delete from table where age22 db select * from table

The result will be as below shows

(1, “user1”, “user1@example.com”,20)

(2, “user2”, “user2@example.com”,21)

(3, “user3”, “user3@example.com”,22)

Note:Where is optional in the delete statement. If no where clause is provided, all data will be deleted.

4 Testing

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) diffcommand can show the difference of two files

2) Install vimand using vimdiffprovide a better looking

Requirements:

Pass provided system tests

Upload a zip file to New E3

Compress the whole project as a zip file

Makefile

The original project already contains a Makefile, your final submission should also be able to compile the shell using Makefile

Passing 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

6 Submission

6.1 E3

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

Make sure your submission contains a Makefile and the result of make command will generate a binary file named shell

If your submission couldn’t be compiled by make cmd, or we can’t find the shellfile as the compiled binary, you will get 0 score

0123456.zip (studentID.zip

`--0123456 (this is your project folder |--include

`--*.h(all the header files |--src

`--*.c(all the source files `--Makefile

6.2 Deadline

You are required to hand in your homework before 2019/05/16 23:59

Late submission is not allowed

7 Discussion Forum

HW3 discussion <HackMD

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