Name : Ahmad Khuzairi Rusydi Bin Ahmad Iskandar
Nickname: Khuzairi
Student id : 2018248894
Tel No: 01129658100

Nickname:  Amar

Student id: 2018641864

Tel No: 0143487525

For each of tables in the database have their own unique attributes which called primary key which is unique on every rows. The tables can be linked together by using the primary key of one table to be the foreign key in the table it linked to. A table can be linked to one or more tables. For entities that have many to many relationship, a bridge table is created to link the tables. The bridge table have 2 primary keys and 2 foreign keys if it connected to 2 tables.

QUESTION 2

LINK : https://www.youtube.com/watch?v=NvrpuBAMddw

 So, from this video, its explained about two tables which is STUDENTS and CLASSESS. So, they want to refer to one of these records but cannot refer to the students name and their operating system because it might have same name or same operating systems. But, we can refer to the student id. So, in the table, we always have one key field which is unique that we set up. So, if we want to relate the information, one way that we can do is just focus on those unique pieces of information. So, from the data between student id and class id, we not only can look at what classes they’re in, but we also can figure out that in one class, there are three students in that class. Between table student and classes , we can have another table which is table ENROLLMENT that can provide more data information about the students. ENROLLMENT table just like the bridge, when STUDENTS and CLASSESS have many to many relationships. So, if ENROLLMENT table do not have unIque identification, we need to add that. We can add many table that related to each other.

 

In this video, I learn about concepts of tables. In a table, we must find the primary key that need to be unique. From the primary key, we can find information that we need such as what students in a certain class. It teach on how bridge table functioning and there will be foreign keys which are primary key from other related tables.  I also learn the relationships of all tables in database and how to identify them. 

Link video = https://youtu.be/NvrpuBAMddw

The video explain about the basic concept of relational database concept. It shows how to write table based on
entity and determine primary key and foreign key.Then, the video also show how to determine relationship between the table in the (ERD).


Question 2

Show the output for SQL statement above

We want to see a list of all departments (that have employees) with the average salary in that department. Rewrite the SQL statement above using SQL analytical query.

 

b) Illustrate how "drilling down" could be done based on items bought.

 

c)    "Pivot" the cube. Explain the operation with a drawing.

 

d)    Based on the cube in Figure 1, draw how "slicing" is done on customer and location.

 

b)      Design a data warehouse model using star schema to track the number of sales of a company. There must be at least FOUR (4) dimension tables.

 

c)      Explain the function of mapper and reducer based on the given case.

 

b)      Illustrate the architecture of MapReduce to perform word count on the given documents.