Reference no: EM13779308
1- What is a database?
2- Data ( ) language is used by the DBA to define schemas.
3- Please describe the three-tier client/server architecture for web applications
4- Give example of system in which it may make sense to use traditional file processing instead of a database approach.
5- Describe what entity represents in an ER mode and provide examples of entities with a physical or conceptual existence.
6- Describe how strong and weak entities differ and provide an example of each.
7- You are required to create a conceptual data model of the data requirement for a company that specializes in IT training. The company has 30 instructors and can handle up to 100 trainees per training session. The company offers five advanced technology courses, each of which is taught by a teaching team of two or more instructors. Each instructor is assigned to a maximum of two teaching teams or may be assigned to do research. Each trainee undertakes one advanced technology course per training session.
(a) Identify the main entity types for the company.
(B) Identify the main relationship types and specify the multiplicity foe each relationship. State any assumptions you make about the data.
(C) Using your answers for (a) and (B), draw a single ER diagram to repressor the data requirement for the company.
8- what is a mission statement?
9- Discuss Tow Limitations of the file-based approach.
10- discuss tow characteristics of the database approach.
11- Describe the purpose of normalization. What are the normalization processes and what happens n each step of the process?
12. Explain the function of each of the clauses in The SELECT statement.
FROM: Specifies the table or tables to be used
WHERE: Filters the rows subject to some condition
GROUP BY: Forms groups of rows with same column name
HAVING: Filters the groups subject to some condition
SELECT: Specifies which columns are to appear in the output
ORDER BY: Specifies the order of the output.
Use the figure above to write a relational algebra expression for the following questions.
13. Retrieve the birthdate and address of the employee(s) whose name -John B. Smith.
14. Retrieve the average salary of all female employees.
15. Retrieve the names of all employees who do not have supervisors.