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.. (לתיקייה המכילה) | |
do you perform stress tests? is there time limitation? | |
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well, yes and no we will not perform stress tests. there is no use for those tests in our course since you not really build a system, the stress is on the SQL server itself. we are looking for the right return values from your implementation. your solution will be tested for its correctness, on a reasonable amount of objects in each test (not millions if that's what you're asking). some tests will take seconds (or less) and some tests will take minutes (few minutes). but we will stop a test execution of it exceeds an hour since it is an unreasonable amount of time to solve the test. |
what should we write in the pdf? | |
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your design: table, constraints, etc.. if you want to add an ERD diagram, go for it, we will appreciate this. you can skip the trivial functions (from your point of view) descriptions but explain the non-trivial ones. this is one of our ways to verify that you understand and know how to use the course material. |
In update movie, can a name be null? | |
| You may assume the name is correct and not null |
Can a movie or viewer object be null, should we check it? | |
| No, the objects will never be null, but they may have some fields with null values |
When a movie is deleted, do we need to also delete all related views and rankings? | |
| Yes |
When a view is deleted, do we need to delete any related rankings? | |
| Yes, if viewer A viewed and disliked movie B then deleted his view of movie B (because it was so bad) then you also need to delete the dislike |
Can a viewer be his own similarViewer? | |
| No |
If a viewer watched 0 movies, who are his similarViewers? | |
| There are no similarViewers. Likewise, such a viewer cannot be a 'most influencing' viewer |
Can a movie with no 'likes' return as a movieRecommendation? | |
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Yes. movieRecommendations can include movies watched by similarViewers that no one liked (as long as at least one similarViewer watched them). Note that because we first ask you to order by rankings this can happen only in the case where there are less than 10 movies liked by similarViewers. The order of movies with the same rank (that includes 0) is by movieID. |
What is considered a similar ranking of a movie (in conditional recommendations)? | |
| Only if the original viewer and the similar viewer ranked (like/dislike) the movie with the same rank they are considered similar rankers. If the original viewer didn't rank the movie then there are no similar rankers. |
How many times can a viewer watch a movie? Is it a yes/no field or a count field? | |
| The viewer only marks if he watched the movie or not. There is no need to keep count of how many times he watched it. |
What is considered Java and what is considered SQL commands? | |
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Any comparison or check on data you perform out of an SQL command is considered Java. NOTE: The only exception to this is checking the number of results returned from executeUpdate and parsing executeQuery. |
Is Like/Dislike an Enum or a boolean. How do we work with Enums in PostgreSQL? | |
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Since we want to work only with SQL and not perform any calculations on data in JAVA, you should treat the rating as an Enum. We added a link to an explanation on Enums in postgreSQL and suggest you google how to use them in "PreparedStatement" objects. | |
| קישור: Link: Ссылка: وصلة: | https://www.postgresql.org/docs/9.1/static/datatype-enum.html |
What are the cs236363 virtual machines? should we use them? | |
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The virtual machines are remote virtualized computers which run on our faculty servers and are pre-installed with everything you need to start doing your homework (InteliJ, Eclipse, Postgres). In short, this will save you time setting up the environment, if you have any troubles. You can use them, but remember that you are connected remotely over the internet, so you may encounter delay in your usage. |
what is the initial postgres superuser password on the virtual machine? | |
| cs236363 |
are we allowed to use commands that where not shown in class or referred to in the HW linkes? | |
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Unfortunately, no. You have to know your way in the course material, even that there are many new SQL commands that solves problem more easily. Some of you showed really nice solutions - we want to say "good work!" to the students who showed us those solutions. |
In updateMovie, do I need to do anything with the movie's name? | |
| No, changes will only occur in the movie's description and you can assume that the id and name will always fit (if you found an entry with the movieId in the table there is no need to check that the movieName is similar) |