Questions from Database Systems

Q: Write a servlet that authenticates a user (based on user names

Write a servlet that authenticates a user (based on user names and passwords stored in a database relation) and sets a session variable called use rid after au- then taxation.

Q: Given the three goals of relational database design, is there any

Given the three goals of relational database design, is there any reason to design a database schema that is in 2NF, but is in no higher-order normal form? (See Exercise 7.19 for the definition of 2NF....

Q: Give a lossless, dependency-preserving decomposition into 3NF of schema

Give a lossless, dependency-preserving decomposition into 3NF of schema R of Exercise 7.1.

Q: Given a relational schema r (A, B, C,

Given a relational schema r (A, B, C, D), does A →→ BC logically imply A →→ B and A →→ C? If yes prove it, or else give a counter example.

Q: Explain why 4NF is a normal form more desirable than BCNF.

Explain why 4NF is a normal form more desirable than BCNF.

Q: What is an SQL injection attack? Explain how it works and

What is an SQL injection attack? Explain how it works and what precautions must be taken to prevent SQL injection attacks.

Q: Normalize the following schema, with given constraints, to 4NF.

Normalize the following schema, with given constraints, to 4NF.

Q: Write pseudo code to manage a connection pool. Your pseudo code

Write pseudo code to manage a connection pool. Your pseudo code must include a function to create a pool (providing a database connection string, database user name, and password as parameters), a fun...

Q: Explain the terms CRUD and REST.

Explain the terms CRUD and REST.

Q: Many web sites today provide rich user interfaces using Ajax. List

Many web sites today provide rich user interfaces using Ajax. List two features each of which reveals if a site uses Ajax, without having to look at the source code. Using the above features, find thre...