Homework means the asker is requesting help with school homework. This lets potential answerers know that they should guide the student in solving the problem, rather than simply showing the complete answer.
0
votes
1answer
39 views
Which is the redundant relationship in this ER Diagram and why?
Which is the redundant relationship in this ER Diagram and why? A few of my friends and I have been trying to figure it out but keep going in circles.
where the attributes of each entity are as ...
0
votes
1answer
71 views
Defining system scope and boundary
I have been given a homework task where I am to create an ER model of a database from a set of client requirements. Another part of this task is to create a diagram that shows the scope and boundary ...
1
vote
0answers
287 views
how to connect values of a new record in a form to a table? [closed]
I have just started working on MS Access 2007. I know how to create a form and add buttons, textboxes, etc
I don't know how to connect my values entered in textbox to my table in database.
How do I ...
2
votes
3answers
216 views
First Normal Form, why is it good and how does it reduce redundancy
I asked a similar question on SO and was advised to ask the type of question here. This is for a course on relational databases. A sample problem asks "how come every table in a relational database ...
4
votes
1answer
193 views
MySQL database normalization 3NF
I have homework where I need to create simple web interface and a DB normalized to 3NF. I've chosen ISP client selfcare as my database purpose. Web interface is no problem, the normalized DB is. After ...
2
votes
1answer
304 views
3NF decomposition + database normalization
I am studying for a test and would like to know if I am on the right track to get the following into 3NF with minimal number of keys for R:
Given relation R(A,B,C,D,E,F,G) and the functional ...
1
vote
1answer
130 views
Size of an empty database
Continuing with my school-project, now I have to estimate the size of the database from here to 5 years. They give me a formula, so, in that formula, one of the values is the size of the empty ...
3
votes
2answers
1k views
Estimate a Database Size
I have to do some project, and need to estimate the DB size.
I'm gonna to use Oracle in the project, because will have a lot of transactions and size.
But in the "presentation" I need to specify, in 5 ...
1
vote
2answers
271 views
Database design experienced view
I want to make a database that stores countries, their respective states, and cities. I am confused how to normalize these. Can anyone help?
My ideas:
Table 1 Countries (id pk, name , code)
...
2
votes
1answer
116 views
ARCHIVELOG mode
Can someone describe in 30 words what ARCHIVEMODE is for?
I found this:
'When you enable this mode redo logs will be archived instead of overwritten.'
but have no idea, what can I write more about ...
3
votes
1answer
186 views
Limiting database security
A number of texts signify that the most important aspects offered by a DBMS are availability, integrity and secrecy. As part of a homework assignment I have been tasked with mentioning attacks which ...
2
votes
2answers
1k views
Return many rows on a plsql Oracle10g
I'm doing a little project and I need to do a plsql to return many rows.
I have someting like:
Table(id, data1, data2, from)
And the user gives me the value of from and I have to return all that.
...
0
votes
1answer
75 views
What are the challenges of administrating an International stock trading database?
I am a student, and have a question for an assignment:
What problems and challenges do database administrators face when designing systems to trade international stocks in real time and 24 hours a ...
2
votes
1answer
352 views
Modelling an E-R diagram for a Pizza place database, need help representing the payment method for the customer
I am modeling a "pizza place" and a customer has an account info. I created a separate table for account info. In here a customer will have an amount spent and method of payment attributes. The ...
1
vote
1answer
2k views
Oracle SQL create view privileges
This is more of a theoritical question but I need help ASAP. Here it is:
With the appropriate use of SQL queries, grant as system
administrators the required access privileges to a database user ...
2
votes
1answer
351 views
Theta join explanation
Given the following question, I'd be glad if someone could help me.
Take the following relational schemes:
R(A, B , C)
S(D, E, F)
where A and D attributes are the primary keys.
Assume to ...
1
vote
2answers
370 views
database normalization 2nf, 3nf
I am doing homework about database normalization. I have to decompose the table into 3nf form showing the steps
here is the initial table:
...
4
votes
2answers
549 views
1 <-> 0..1 relationship
I have "1 <-> 0..1 relationship". For example:
There is a set of users. Some users are customers.
Thus we have two tables: the table users and the table customers.
What is the best way to ...
5
votes
3answers
112 views
Dynamic temporary index creation
In my undergrad databases course, my professor mentioned that some DBMS software is so advanced that it can detect when a long-running query would benefit from an index. The DBMS can then create that ...
4
votes
2answers
988 views
Concurrent Transactions vs Simultaneous Transactions
Chapter 6 of David Kroenke's Database Concepts: Database Administration
Is my understanding correct that in a database, simultaneous transactions don't really happen. Instead, it is a concurrent ...
4
votes
1answer
779 views
Calculate months between two dates
For a University course I've been given the following task
Suppose that we have an employee table like (first_name, last_name, salary, hire_date, ...). There is regulation which states that every ...
4
votes
1answer
918 views
Why doesn't INSERT AFTER Trigger add all results?
I'm working on the exercises for db-class.org where we have to write a trigger that makes new students named 'Friendly' automatically like everyone else in their grade. That is, after the trigger ...
