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Project 2 discussion
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fatma.meawad@guc.edu.eg

GUC Faculty

Join Date: 10/7/2008
Posts: 14

Posted: 5/4/2009 9:54:02 PM

For khalid,


Khalid, you don't need to do parsing or anything like that. The database does this anyway.
You should trigger the processing of a query from the start. If you trace the execution of a query from the start even from a client, you will see statement which will take you to how simpledb start the query processing. simpledb.planner.createQuery ...... and this method you give it the query string and please continue tracing to understand
mina.hanna@student.guc.edu.eg

Student

Join Date: 9/19/2008
Posts: 5

Posted: 5/4/2009 10:02:12 PM

Hi Dr.Fatma,

I have made a tree data structure and a DisplayPanel which is a panel that takes the tree root and displays the tree.

Can I publish them so that anyone can use it?

Thanks
mohamed.khamis@student.guc.edu.eg

Student

Join Date: 9/17/2008
Posts: 1

Posted: 5/5/2009 8:13:20 AM

Dear Dr. Fatma,

According to the first lecture, we were supposed to have 5 projects each worth 5%, so is this project worth 5% as well or more? and is there an "x out of 5 projects" policy? and concerning the deadline extension, is it still Friday midnight or has it been further extended? and will partially complete projects be graded?
fatma.meawad@guc.edu.eg

GUC Faculty

Join Date: 10/7/2008
Posts: 14

Posted: 5/5/2009 11:44:49 AM

For Mina,

That is very nice of you Mina
You can publish it for your colleagues of course
How will you announce it to them
fatma.meawad@guc.edu.eg

GUC Faculty

Join Date: 10/7/2008
Posts: 14

Posted: 5/5/2009 11:48:19 AM

For mohamed,

Yes, we did say 5 projects and of course, it is very obvious, we can't have 5. So most probably we will end up with 3 projects. I will give the second project more value than the first one of course.

After friday midnight (saturday morning), there is no deadline extension
Yes partially completed projects will be graded of course.
khalid.mahrous@student.guc.edu.eg

Student

Join Date: 9/20/2008
Posts: 2

Posted: 5/5/2009 7:49:57 PM

Dear Dr Fatma

Is it OK if we used NetBeans for the GUI implementation ??
The query will be Logically right or not ??
Muaz.Al-Jarhi@student.guc.edu.eg

Student

Join Date: 10/16/2008
Posts: 6

Posted: 5/6/2009 11:10:55 PM

Dear Dr. Fatma,

ist the createPlan for a query creates a query tree for that query? Then how to get the nodes of the tree or the value at the nodes of the tree? I did not find any methods in the interface plan that get the values at the nodes of the tree.
fatma.meawad@guc.edu.eg

GUC Faculty

Join Date: 10/7/2008
Posts: 14

Posted: 5/7/2009 10:35:27 AM

Muaz,

The createPlan starts the processing process. There is no actual tree with nodes, it just executes with the logic of a tree, so you draw the nodes as you follow the steps. The table is leaf for example and if there is a select operation on it then it is an internal node, exactly like what we have in the slides
mohamed.hazem@student.guc.edu.eg

Student

Join Date: 10/18/2008
Posts: 4

Posted: 5/7/2009 11:28:14 PM

Can I use a vertical Tree instead of a horizontal one ?
Like the trees used for hierarchal file management.

like this one http://www.nabble.com/file/p20491149/tree.png
fatma.meawad@guc.edu.eg

GUC Faculty

Join Date: 10/7/2008
Posts: 14

Posted: 5/8/2009 11:27:40 AM

Hazem
I dunno how you plan to use this
But use anything as long as I can see leaf tables, then internal nodes with operations.
It doesn't matter if they look like an actual normal tree as long as the operands, operations and the lines connecting them are valid.

Good luck
Muaz.Al-Jarhi@student.guc.edu.eg

Student

Join Date: 10/16/2008
Posts: 6

Posted: 5/8/2009 12:09:11 PM

In order to use query plans I need use transactions but I get null pointer exception in simpledb.tx.recovery.StartRecord at method writeToLog() (logMgr = null). Of-course before using any transaction I initialise it to the constructor of the class (ex. transaction tx = new transaction();). What else should I do or What should I set a transaction to before using it?
mohamed.hazem@student.guc.edu.eg

Student

Join Date: 10/18/2008
Posts: 4

Posted: 5/8/2009 12:17:37 PM

Quote:
Quoted From Muaz.Al-Jarhi@student.guc.edu.eg:

In order to use query plans I need use transactions but I get null pointer exception in simpledb.tx.recovery.StartRecord at method writeToLog() (logMgr = null). Of-course before using any transaction I initialise it to the constructor of the class (ex. transaction tx = new transaction();). What else should I do or What should I set a transaction to before using it?




I don't think you need to do all this, so far I haven't touched any classes but the BasicQueryPlanner.java which is inside the simpledb.planner package.
Muaz.Al-Jarhi@student.guc.edu.eg

Student

Join Date: 10/16/2008
Posts: 6

Posted: 5/8/2009 12:21:22 PM

What? inorder to create any plan like the one in the BasicQueryPlanner you will need tp input to the method the transaction (and the query data).
mohamed.hazem@student.guc.edu.eg

Student

Join Date: 10/18/2008
Posts: 4

Posted: 5/8/2009 12:50:56 PM

Quote:
Quoted From Muaz.Al-Jarhi@student.guc.edu.eg:

What? inorder to create any plan like the one in the BasicQueryPlanner you will need tp input to the method the transaction (and the query data).




I wonder why do you want to manually create your plans.

BasicQueryPlanner is a planner that creates all the needed plans for you ... All you need to do is to extract the plans information(blocksAccessed, projection fields, ... etc) from the plans created by the planner ... correct me if I'm wrong.
Muaz.Al-Jarhi@student.guc.edu.eg

Student

Join Date: 10/16/2008
Posts: 6

Posted: 5/8/2009 1:59:07 PM

Tell me how are you going to use the BasicQueryPlanner? arent you going to use the mehod inside it which is createPlan(QueryData data, Transaction tx)? else how will you use it? Of-course you know that it has only this method.
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