makeyourowndatabase

A toy database implemented in java!

Run this project

Run this project in IDEA:

• run Main class

Run this project in terminal:

git clone https://github.com/Chang-LeHung/makeyourowndatabase.git
cd makeyourowndatabase
mvn package
java -jar target/makeyourdatabase-1.0-SNAPSHOT-jar-with-dependencies.jar  

Results are like following images:

>>>select * from student;
executing: select * from student;
+-----------------------+-------------+
|         name          |     id      |
+-----------------------+-------------+
| StringData{param='A'} | Int{val=1}  |
| StringData{param='A'} | Int{val=2}  |
| StringData{param='A'} | Int{val=3}  |
| StringData{param='A'} | Int{val=4}  |
| StringData{param='A'} | Int{val=5}  |
| StringData{param='B'} | Int{val=6}  |
| StringData{param='B'} | Int{val=7}  |
| StringData{param='B'} | Int{val=8}  |
| StringData{param='B'} | Int{val=9}  |
| StringData{param='C'} | Int{val=10} |
| StringData{param='C'} | Int{val=11} |
| StringData{param='C'} | Int{val=12} |
| StringData{param='D'} | Int{val=13} |
| StringData{param='D'} | Int{val=14} |
+-----------------------+-------------+
Size of queried table : 14
>>>delete from student where name=='A';
executing: delete from student where name=='A';
Delete OK;
>>>select * from student;
executing: select * from student;
+-----------------------+-------------+
|         name          |     id      |
+-----------------------+-------------+
| StringData{param='B'} | Int{val=6}  |
| StringData{param='B'} | Int{val=7}  |
| StringData{param='B'} | Int{val=8}  |
| StringData{param='B'} | Int{val=9}  |
| StringData{param='C'} | Int{val=10} |
| StringData{param='C'} | Int{val=11} |
| StringData{param='C'} | Int{val=12} |
| StringData{param='D'} | Int{val=13} |
| StringData{param='D'} | Int{val=14} |
+-----------------------+-------------+
Size of queried table : 9
>>>

>>> select name, avg(id), max(id), min(id), count(name) from stu group by name having avg(id) > 6;
executing: select name, avg(id), max(id), min(id), count(name) from stu group by name having avg(id) > 6;
+-------------+-------------+-------------------------+-------------+-----------------+
| count(name) |   max(id)   |          name           |   min(id)   |     avg(id)     |
+-------------+-------------+-------------------------+-------------+-----------------+
| Int{val=3}  | Int{val=14} | StringData{param='tyx'} | Int{val=12} | Float{val=13.0} |
| Int{val=1}  | Int{val=7}  |  StringData{param='B'}  | Int{val=7}  | Float{val=7.0}  |
| Int{val=1}  | Int{val=8}  |  StringData{param='C'}  | Int{val=8}  | Float{val=8.0}  |
| Int{val=1}  | Int{val=9}  |  StringData{param='D'}  | Int{val=9}  | Float{val=9.0}  |
| Int{val=1}  | Int{val=10} |  StringData{param='E'}  | Int{val=10} | Float{val=10.0} |
| Int{val=1}  | Int{val=11} |  StringData{param='F'}  | Int{val=11} | Float{val=11.0} |
+-------------+-------------+-------------------------+-------------+-----------------+
Size of queried table : 6
>>>

>>>select count(name) from stu;
executing: select count(name) from stu;
+-------------+
| count(name) |
+-------------+
| Int{val=14} |
+-------------+
Size of queried table : 1
>>>

select * from stu where name like "%harden%";
executing: select * from stu where name like "%harden%";
+----------------------------------+-------------+
|               name               |     id      |
+----------------------------------+-------------+
| StringData{param='james_harden'} | Int{val=21} |
| StringData{param='james_harden'} | Int{val=19} |
| StringData{param='james_harden'} | Int{val=18} |
+----------------------------------+-------------+
Size of queried table : 3
>>>select * from stu;
executing: select * from stu;
+------------------------------------+-------------+
|                name                |     id      |
+------------------------------------+-------------+
|    StringData{param='huchang'}     | Int{val=1}  |
|    StringData{param='huchang'}     | Int{val=2}  |
|    StringData{param='huchang'}     | Int{val=3}  |
|    StringData{param='huchang'}     | Int{val=4}  |
|     StringData{param='asdsad'}     | Int{val=5}  |
|       StringData{param='A'}        | Int{val=6}  |
|       StringData{param='B'}        | Int{val=7}  |
|       StringData{param='C'}        | Int{val=8}  |
|       StringData{param='D'}        | Int{val=9}  |
|       StringData{param='E'}        | Int{val=10} |
|       StringData{param='F'}        | Int{val=11} |
|      StringData{param='tyx'}       | Int{val=12} |
|      StringData{param='tyx'}       | Int{val=13} |
|      StringData{param='tyx'}       | Int{val=14} |
| StringData{param='"lebron_james"'} | Int{val=15} |
|  StringData{param='lebron_james'}  | Int{val=16} |
|  StringData{param='lebron_james'}  | Int{val=17} |
|  StringData{param='james_harden'}  | Int{val=21} |
| StringData{param='"lebron_james"'} | Int{val=20} |
|  StringData{param='james_harden'}  | Int{val=19} |
|  StringData{param='james_harden'}  | Int{val=18} |
+------------------------------------+-------------+
Size of queried table : 21
>>>

select * from stu;
executing: select * from stu;
+------------------------------------+-------------+
|                name                |     id      |
+------------------------------------+-------------+
|    StringData{param='huchang'}     | Int{val=1}  |
|    StringData{param='huchang'}     | Int{val=2}  |
|    StringData{param='huchang'}     | Int{val=3}  |
|    StringData{param='huchang'}     | Int{val=4}  |
|     StringData{param='asdsad'}     | Int{val=5}  |
|       StringData{param='A'}        | Int{val=6}  |
|       StringData{param='B'}        | Int{val=7}  |
|       StringData{param='C'}        | Int{val=8}  |
|       StringData{param='D'}        | Int{val=9}  |
|       StringData{param='E'}        | Int{val=10} |
|       StringData{param='F'}        | Int{val=11} |
|      StringData{param='tyx'}       | Int{val=12} |
|      StringData{param='tyx'}       | Int{val=13} |
|      StringData{param='tyx'}       | Int{val=14} |
| StringData{param='"lebron_james"'} | Int{val=15} |
|  StringData{param='lebron_james'}  | Int{val=16} |
|  StringData{param='lebron_james'}  | Int{val=17} |
|  StringData{param='james_harden'}  | Int{val=21} |
| StringData{param='"lebron_james"'} | Int{val=20} |
|  StringData{param='james_harden'}  | Int{val=19} |
|  StringData{param='james_harden'}  | Int{val=18} |
+------------------------------------+-------------+
Size of queried table : 21
>>>update stu set name=new where name == "tyx";
executing: update stu set name=new where name == "tyx";
Update OK;
>>>select * from stu;
executing: select * from stu;
+------------------------------------+-------------+
|                name                |     id      |
+------------------------------------+-------------+
|    StringData{param='huchang'}     | Int{val=1}  |
|    StringData{param='huchang'}     | Int{val=2}  |
|    StringData{param='huchang'}     | Int{val=3}  |
|    StringData{param='huchang'}     | Int{val=4}  |
|     StringData{param='asdsad'}     | Int{val=5}  |
|       StringData{param='A'}        | Int{val=6}  |
|       StringData{param='B'}        | Int{val=7}  |
|       StringData{param='C'}        | Int{val=8}  |
|       StringData{param='D'}        | Int{val=9}  |
|       StringData{param='E'}        | Int{val=10} |
|       StringData{param='F'}        | Int{val=11} |
|      StringData{param='new'}       | Int{val=12} |
|      StringData{param='new'}       | Int{val=13} |
|      StringData{param='new'}       | Int{val=14} |
| StringData{param='"lebron_james"'} | Int{val=15} |
|  StringData{param='lebron_james'}  | Int{val=16} |
|  StringData{param='lebron_james'}  | Int{val=17} |
|  StringData{param='james_harden'}  | Int{val=21} |
| StringData{param='"lebron_james"'} | Int{val=20} |
|  StringData{param='james_harden'}  | Int{val=19} |
|  StringData{param='james_harden'}  | Int{val=18} |
+------------------------------------+-------------+
Size of queried table : 21
>>>