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| A note about InterestingTags in HW2 | To make things a bit easier for you we've decided to give you a choice.
When encountering a question with no answers you may choose one of the following options:
1) count the question when calculating the tag's score and print the tag with number of answers 0.
2) don't count the question and don't print the question.
Choose which option you prefer. |
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| Created on 21/5/2013, 14:44:06 |
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| HW2 postponed | Due to connectivity problems in the server (dropped connections, etc.), submission of HW2 is postponed to Sunday.
The server problems cannot be fixed without a restart (which will take a lot of time, possibly 24 hours).
To allow you all to properly check your solutions, we will not fix it now.
Instead we postpone the deadline.
Don't wait until the last moment to check your solution.
Further delays and postponements due to server connectivity issues will not be approved!
If you got permission to submit late, you may add the number of days approved to the new deadline.
Also, be sure to check that you have read all posts on the FAQ. |
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| Created on 21/5/2013, 13:07:33 |
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| HW1 solution is published | |
| Created on 20/5/2013, 16:19:29 |
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| HW1 grades are published | Some students submitted alone without approval.
This time we did not deduct points for that.
Next time you will lose points (if you a valid a reason for submitting alone you need to contact the TA in charge and get his approval).
Also, there were a couple of students who did not enroll to the course site and therefore we cannot enter their grades.
If you submitted the homework but did not get a grade, make sure that you are enrolled to the course site and contact the TA in charge. |
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| Created on 19/5/2013, 18:41:21 |
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| Error in HW2 Example.sol | there was an error in the example solution we gave you.
the corrected version has been uploaded to the site.
also, any time we find frequently asked questions or we need to exp[lain or clarify something we do that in the FAQ section so make sure you read frequently. |
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| Created on 2/5/2013, 19:06:48 |
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| Omer's office hour today | | Due to unexpected circumstances Omer's office hours today will be postponed to tomorrow (Wednesday) at 17:30 |
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| Created on 30/4/2013, 14:44:40 |
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| New DRC/RA slides available online | We've uploaded new slides regarding the differences and similarities between queries in DRC and queries in RA.
These slides are also an example for translating queries from one language to another.
The slides are available in the supporting slides section |
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| Created on 29/4/2013, 10:39:37 |
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| Created on 23/4/2013, 17:42:45 |
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| Last updated on 29/4/2013, 17:07:52 |
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| Created on 22/4/2013, 16:43:10 |
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| Created on 21/4/2013, 19:18:20 |
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| Daniel tutorial next week | As previously announced, the tutorial will on Wednesday at 13:30 instead of its usual time.
The tutorial will be in classroom Taub 6. |
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| Created on 10/4/2013, 20:26:50 |
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| Abstract Lecture 3 | We introduced relational algebra (RA) following essentially the slides of previous lectures on relational algebra (slides 1-14).
Basic operations: Projection, Cartesian product, selection, union, intersection, set difference, and renaming. In selection only boolean combinations of equalities and comparisons are allowed.
We discussed additional examples:
1. Different realizations of of ER-diagrams, rather than our standard
interpretation.
2. A database with a "direct ancestor relation (DA)" only.
We discussed queries defining various family relations such as
"brother", "granadfather", "cousin", "n-th cousin k-removed", etc.
The examples from slides 19-24 should be studied as homework.
We also discussed proving independence of the basic operations:
cartesian products (projection) cannot be expressed with the remaining basic operations.
Intersection can be expressed with the remaining basic operations.
We left as an exercise: Show that set difference cannot be expressed with the remaing basic operations.
Next lecture: More on RA, comparing RA and basic SQL. |
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| Created on 9/4/2013, 11:17:38 |
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| Thursday tutorial on the 18th of April | Daniel will not be able to make it to the tutorial on Thursday 18/4.
Instead Daniel will have a tutorial on Wednesday 17/4 at 13:30 (classroom will be announced later).
This is a one time change! |
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| Created on 8/4/2013, 17:22:16 |
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| HW1 FAQ is online | Corrections to the homework and answer to repeated questions will be posted in the FAQ.
You should check it regularly and make sure you check it before submitting the homework. |
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| Created on 4/4/2013, 22:31:47 |
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| Created on 1/4/2013, 22:57:54 |
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| Created on 20/3/2013, 14:58:49 |
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| Lecture class | | After the Passover break, all Lectures (only lectures, not tutorials) will be in Taub 7. |
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| Created on 17/3/2013, 16:26:23 |
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| SQL server restart | Due to a permissions issue we had to completely restart the server.
It is back online and you can now go ahead and create your users.
The few students that have already created their users, unfortunately those users no longer exist so please recreate them. |
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| Created on 12/3/2013, 23:05:57 |
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| Abstract Lecture 1 | Lecture 1 (10.3.2013)
- General remarks about the course and its homepage.
- Genral remark on learning and exams.
- Exampes of large reslient database:
Timetables of European train network, Insurance companies, Banks
- Many of these were first designed even 50 years ago
and evolve very slowly.
- Introducing Entity-Relationship diagrams, I
Entitities (autonomous tables)
Relationships (tables linking Entities)
Keys and Inclusions
In Lecture 2 we will continue with Entity-Relationship diagrams. |
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| Created on 11/3/2013, 14:11:15 |
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| Course material rearranged | We have rearranged the course material into 5 categories.
You can find explanation about the categories in the course material section.
Also, each week we will upload an abstract for that week's lecture so if you missed a lecture you will know what you have missed. |
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| Last updated on 8/3/2013, 20:22:35 |
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| A few submission guidelines | 1) All submissions should be in pairs, unless given written permission from the TA in charge.
2) All extension request must be submitted to the TA in charge at least 24 hours prior to hw submission. Any requests sent less than 24 hours before submission will be declined.
3) If you are given an extension, the submission hour stays the same. i.e if you were supposed to submit by 12:30 and was given a 1 day extension, you should submit by 12:30 the next day.
4) All late submissions (both approved and non-approved) should be submitted to the mail box of the TA in charge of the homework on the 5th floor (in time submission should be submitted to the course's mail box on the 1st floor).
(late submission of the wet hw should be sent to the email address of the TA in charge of the homework) |
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| Created on 3/3/2013, 16:41:00 |
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| 234293 as a Prerequisite | Students might need background in Logic for some parts of the course.
Students that didn't take the prerequisite course 234293 are allowed to take the course, but they do so at their own risk (the risk being not knowing any logic).
In such cases, we recommend reading book, notes and slides to reduce the risk. |
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| Created on 3/3/2013, 16:39:16 |
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| SQL Accounts | Every student can now open an SQL account. An account allows you to practice SQL on sample tables, and is essential for testing your wet assignment.
Please read the "SQL accounts" subsection in FAQ, where all details are provided, and make sure you indeed have an account.
Good Luck! |
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| Created on 3/3/2013, 16:38:54 |
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| Course Material | The presentations from the previous semester have been uploaded to the course site.
They are currently relevant to this semester but that may change during the semester. |
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| Created on 3/3/2013, 16:38:37 |
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| Welcome to Database System course | May we all have a fruitful and enjoyable semester,
The course staff. |
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| Created on 3/3/2013, 16:37:45 |
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