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標題: Database Systems Design, Implementation, and Management [打印本頁]
作者: et1984    時間: 2012-2-8 00:33     標題: Database Systems Design, Implementation, and Management

Anyone studied this course or book before? or maybe now ? ^_^
作者: ACC-HE    時間: 2012-2-8 11:13

shouldn't be too hard.  PK, FK, 1st, 2nd, 3rd normal form, usually in SQL Server?
作者: et1984    時間: 2012-2-9 02:45

hahah....>.<" I guess you are good that's why you said shouldn't be hard I just started it....not into SQL yet but starting with the basic of PK, FK, 1NF, 2NF, 3NF but too much terms that's messing me up hahahah
作者: rainbow-davie    時間: 2012-2-9 04:02

still SQL... omg...  just wondering what programming language does university teaching now?
作者: et1984    時間: 2012-2-10 11:08

still SQL... omg...  just wondering what programming language does university teaching now?
rainbow-davie 發表於 2012-2-9 04:02



I think there should be quite a few programming languages hehe
作者: et1984    時間: 2012-2-10 11:10

Just wondering if I can get some help here.

Between the  current address entity and student entity what's the best relationship between them? 1:1 or 1:M?
作者: ACC-HE    時間: 2012-2-10 11:17

depends.

but 1:1 seems ok.
作者: et1984    時間: 2012-2-10 17:10

depends.

but 1:1 seems ok.
ACC-HE 發表於 2012-2-10 11:17



1:1 seems ok but I mentioned 1:M because what if the students live together in the same address then an address will have one or more students >.<"

actually the part I'm having headache with is the prof is asking us to make the diagram so that students with their pass 10 addresses so if it is 1:M for current address to  students then it'll be M:N for past addresses to students.  But I don't know what composite entity I should use in between past addresses to students.
作者: Prelude    時間: 2012-2-10 17:15

In real application, it's 1:M.
作者: ACC-HE    時間: 2012-2-10 17:19

1:1 seems ok but I mentioned 1:M because what if the students live together in the same address t ...
et1984 發表於 2012-2-10 17:10



    Ya, but think in real application, they should not be FK to the same address 'cause what if one of them changed his address? then you're changing his roommate's address too.
作者: yuusaku    時間: 2012-2-10 18:50

if not SQL, then NoSQL?

回復 4# rainbow-davie
作者: et1984    時間: 2012-2-10 22:36

Ya, but think in real application, they should not be FK to the same address 'cause what if o ...
ACC-HE 發表於 2012-2-10 17:19



    oh ya true!!!! ah ha!
作者: et1984    時間: 2012-2-10 22:37

In real application, it's 1:M.
Prelude 發表於 2012-2-10 17:15



    but as ACC-HE said...it does make sense though
作者: et1984    時間: 2012-2-11 00:20

if not SQL, then NoSQL?

回復  rainbow-davie
yuusaku 發表於 2012-2-10 18:50



haha...but anyways I'm still studying the I guess this is still called the theory part.  SQL starts next week but I have a project to hand  in
作者: rainbow-davie    時間: 2012-2-12 02:00

if not SQL, then NoSQL?

回復  rainbow-davie
yuusaku 發表於 2012-2-10 18:50


yes.. I'm using Mongo in few projects since a year ago.  Also looking into other NoSQL db.    and using node.js   

I already left SQL and php. LAMP is a past tense for me.  and I love the new technology.  It is extremely good for web development.
作者: yuusaku    時間: 2012-2-12 22:20

本帖最後由 yuusaku 於 2012-2-12 22:22 編輯

I've been looking into NoSQL out there, the one that I've paid attention the most is Cassandra, it was covered by quite a few sessions in a java seminar(NFJS)

the dba is still insisting that eventually-consitent won't fit our need, we are still stuck with rdbms so far.  and we need to tackle the scalability issue sooner rather than later

regarding node js, how do you like it so far? do you use library like socket io?

yes.. I'm using Mongo in few projects since a year ago.  Also looking into other NoSQL db.    an ...
rainbow-davie 發表於 2012-2-12 02:00
作者: rainbow-davie    時間: 2012-2-13 02:20

Cassandra is good when you work with multiple data centre.  however, the set up is not easy.  

Of course your DBA will say it.  Job security!! NoSQL doesn't require a DBA.  
for example, in my team, senior engineer (like me) can already handle the data design and programming (actually, it is inside the application already).   The infrastructure is handled by hardward Operation guy.   So, we don't need DBA to handle schema or normalizing DB.  lol   DBA is expensive~~~   oh. and scaling can be done by ops guy easily.  I can also do that too.  

Scale in rdbm is tough.  Vertical scaling is expensive in hardware.  Horizontal scaling is fxxking complicate and easily to crash.  

When I first use Mongo and node.js, my other coworkers have doubt but now, they like Mongo.   And I'm bringing people to try node.js.      

I recommend you to find a small (very small) project to use in your company.  more like caching json data, etc. and try with Mongo. of course, the project is best to be small in scope but high in traffic.   Then your PM will be impressed.   

I had a launch last year Oct and other PHP servers (15) were over 100% , and MySQL DB servers were crazy.  But my 5 node.js servers and a simple replicated MongoDB just sitting calm with no more than 40% usage.

i have done tones of load testing with Node & mongo, and I am very impressed by the performance and the non-blocking nature.

Well. nodejs.   I love it.  No more php.  Of course, doing node is very easily to start, but then tough to master it. Once you master it, it is very easy.   The challenge I find is that, instead of sequential programming, you have to think in Event & callback way.  Very careful in async nature.   Also, node.js is not for junior. You have to have understanding of web technologies and know what you are doing.   no lazy programming.  

I use tones of library...except socket.io.  haahh but I will use it soon.  Expressjs is a must to use.  I also recommend you to join the node.js facebook or google+ group.  

for mongo, recommend you to join any meet up nearby.  I went to the one in Seattle last year.  It was good, You will have directly contact with the Mongo creator and engineer.


Trust me or not... Node + Mongo will be the key technology for web development in next 3-5 years.
作者: yuusaku    時間: 2012-2-15 12:46

本帖最後由 yuusaku 於 2012-2-15 12:48 編輯

My company is still having similar stack like LAMP for front end, replaced MySQL with Postgres, on top of that, there is a memcache in front of it, for the http sessions.  We have been thinking to upgrade the PHP4 to 5, but new features always go higher priority than the system tasks.  We also tried Symfony, but I feel that it defeated the purpose of interpreted language like PHP, since it requires compiling.  

I am a senior developer on the back end team, my duty involves migrating from J2EE 1.4 to Spring and addressing scalability.  Recently we are looking into supporting push, desktop browser and mobile browser, unfortunately only the minority of browsers can do web socket yet.  From the prototyping we did on socket.io, it really impresses me that it supports the latest web socket, flash, long comet, or periodic ajax.  

I've been doing a lot integration across system using non-blocking events listener/callback/messaging, but don't deal them much at code level, like node.js.  

For the prototyping of node.js+socket.io, I'm trying to hook it up to ActiveMQ, if that works well...I can foresee that could greatly reduce our DB hit than our existing periodic ajax polling...

Alright, no more hi jacking this thread

Glad to see another LYK is in the same sector
作者: rainbow-davie    時間: 2012-2-15 13:17

By the way yuusaku, you can look into npmjs  for node package or github for any lib that can help you on ActiveMQ.
作者: yuusaku    時間: 2012-2-15 14:50

yup, npm is pretty handy, and i'm following the tutorial on express:

http://expressjs.com/screencasts.html



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