Hello Friends,
I have a kind of requirement like, Student & Question are entities.
Both Entity are in many-to-many relation.
I would like to represent my idea is something likewise(refer below screen-shot. please correct me if any improvement is possible).
I would like to know from you guys is that,
1) is the above mentioned DB-design is good ? is there any improvement
then let me know.
And second one is related to query(JPQL),
2) it's most important, in spring-data-jpa, how would I implement in
such a way so that, even though user has not answered question then
also, those question needs to reflect under user-profile page that
this question is still not answered. Refer below screen-shot about
an expectation of this(second one) question.
Any help would be really appreciable!!
Related
for my current project, I'm building a survey builder from scratch (some of the requirements are very unique). I'm having quite a hard time with the data model since it seems overly normalized to me. I'd love some input on it (since I'm not the most experienced programmer).
The situation:
Most of the question types stand by themselves and don't have any relation to surrounding questions (e. g. "How do you like the weather?" - "Fine"). Other questions need a module that relates them with their surrounding questions (e. g. Likert scale questions -- How satisfied are you with: a.) your school? your workplace?).
Currently, my solution is to put every question in a module. This results in a lot of modules with just one question in them.
Here is a sketch explaining the problem:
The normalized data structure looks like this (I'm using SQL):
looks ok. you will also need a place for the actual responders, and another for the actual responses those responders give to the questions.
I'm trying to design a database for an application where users can submit and take tests.
Here is what I got so far:
http://i.stack.imgur.com/pgf7m.png
I'm particularly unsure about the relation between Test_Testee and QuestionAnswer_TesteeAnswer. I need a way to connect the answers & the questions & the tests, but I'm afraid the solution I came up with is a bit naive.
If you can see anything wrong with my design, or if you would do something different please say so, I'm just looking for some general feedback.
Thanks!
It feels a little off.
The testee should take the test (one or more times) - possibly as shown in test_testee.
for each taking of the test, the testee should have 0 or 1 answers to each question:
this is a link between test_testee and question that includes the given answer... one table.
We are building a survey engine for our internal use. I would like to know how to persist the question branching logic into the database? Any body done this before or any ideas on the schema for the database?
If the user responses with an answer, we need to skip to the next questions based on the logic added to the questions Each question can have multiple logic added to it.
For eg:
Question: Is it Sunny, Raining or Cloudy?
Answer: Raining.
The next question should be based on the previous answer.
if(Raining)
{
}
if(Sunny)
{
}
if(Cloudy)
{
}
how do I persist the above to the database and go from there?
Any bright ideas ?
You're essentially looking to persist a decision tree into a database. You'd want to store each question as a node and, in the interests of a normalized database, store the edges in a separate table relating questions that depend on other questions (directed edges), and walk as appropriate.
Edit: A simple design can be two tables: Questions and Edges. Questions just has id and question text. Edges can be answered_question_id, next_question_id, and answer. The first table is self-explanatory. The second table lists that if a question answered_question_id is asked and answered with something that either equals to or matches answer, forward to question next_question_id next.
I read up on database structuring and normalization and decided to remodel the database behind my learning thingie to reduce redundancy.
I have different types of entries that can be learned. Gap texts/cloze tests (one text, many gaps) and simple known-unknown (one question, one answer) types.
Now I'm in a bit of a pickle:
gaps need exactly the same columns in the user table as question-answer types
but they need less columns than question-answer types (all that info is in the clozetests table)
I'm wishing for a "magic" foreign key that can point both to the gap and the terms table. Of course their ids would overlap though. I don't like having both a term_id and gap_id in the user_terms, that seems unelegant (but is the most elegant I can come up with after googling for a while, not knowing what name this pickle goes by).
I don't want a user_gaps analogue to user_terms, because then I'd be in the same pickle when it comes to the table user_terms_answers.
I put up this cardboard cutout collage of my schema. I didn't remove the stuff that isn't relevant for this question, but I can do that if anyone's confusion can be remedied like that. I think it looks super tidy already. Tidier than my mental concept of this at least.
Did I say any help would be greatly appreciated? Answerers might find themselves adulated for their wisdom.
Background story if you care, it's not really relevant to the question.
Before remodeling I had them all in one table (because I added the gap texts in a hurry), so that the gap texts were "normal" items without answers, while the gaps where items without questions. The application linked them together.
Edit
I added an answer after SO coughed up some helpful posts. I'm not yet 100% satisfied. I try to write views for common queries to this set up now and again I feel like I'll have to pull application logic for something that is database turf.
As mentioned in the comment, it is hard to answer without knowing the whole story. So, here is a story and a model to match. See if you can adapt this to you example.
School of (foreign) languages offers exams for several levels of language proficiency. The school maintains many pre-made tests for each level of each language (LangLevelTestNo).
Each test contains several (many) questions. Each question can be simple or of the close-text-type. Correct answers are stored for each simple question. Correct terms are stored for each gap of each close-text question.
Student can take an exam for a language level and is presented with one of the pre-made tests. For each student exam, the exam form is maintained which stores students answers for each question of the exam. Like a question, an answer may be of a simple of of a close-text-type.
After editing my question some Stackoverflow started relating the right questions to me.
I knew this was a common problem, but I really couldn't find it, just couldn't come up with the right search terms, I guess.
The following threads address similar problems and I'll try to apply that logic to my own design. They all propose adding a higher-level description for (in my case terms and gaps) like items. That makes sense and reflects the logic behind my application.
Relation Database Design
Foreign Key on multiple columns in one of several tables
Foreign Key refering to primary key across multiple tables
And this good person illustrates how to retrieve the data once it's broken up across tables. He also clues me to the keyword class table inheritance, so now I know what to google.
I'll post back with my edited schema once I've applied this. It does seem more elegant like this.
Edited schema
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I'm working on a fairly simple survey system right now. The database schema is going to be simple: a Survey table, in a one-to-many relation with Question table, which is in a one-to-many relation with the Answer table and with the PossibleAnswers table.
Recently the customer realised she wants the ability to show certain questions only to people who gave one particular answer to some previous question (eg. Do you buy cigarettes? would be followed by What's your favourite cigarette brand?, there's no point of asking the second question to a non-smoker).
Now I started to wonder what would be the best way to implement this conditional questions in terms of my database schema? If question A has 2 possible answers: A and B, and question B should only appear to a user if the answer was A?
Edit: What I'm looking for is a way to store those information about requirements in a database. The handling of the data will be probably done on application side, as my SQL skills suck ;)
Survey Database Design
Last Update: 5/3/2015
Diagram and SQL files now available at https://github.com/durrantm/survey
If you use this (top) answer or any element, please add feedback on improvements !!!
This is a real classic, done by thousands. They always seems 'fairly simple' to start with but to be good it's actually pretty complex. To do this in Rails I would use the model shown in the attached diagram. I'm sure it seems way over complicated for some, but once you've built a few of these, over the years, you realize that most of the design decisions are very classic patterns, best addressed by a dynamic flexible data structure at the outset.
More details below:
Table details for key tables
answers
The answers table is critical as it captures the actual responses by users.
You'll notice that answers links to question_options, not questions. This is intentional.
input_types
input_types are the types of questions. Each question can only be of 1 type, e.g. all radio dials, all text field(s), etc. Use additional questions for when there are (say) 5 radio-dials and 1 check box for an "include?" option or some such combination. Label the two questions in the users view as one but internally have two questions, one for the radio-dials, one for the check box. The checkbox will have a group of 1 in this case.
option_groups
option_groups and option_choices let you build 'common' groups.
One example, in a real estate application there might be the question 'How old is the property?'.
The answers might be desired in the ranges:
1-5
6-10
10-25
25-100
100+
Then, for example, if there is a question about the adjoining property age, then the survey will want to 'reuse' the above ranges, so that same option_group and options get used.
units_of_measure
units_of_measure is as it sounds. Whether it's inches, cups, pixels, bricks or whatever, you can define it once here.
FYI: Although generic in nature, one can create an application on top of this, and this schema is well-suited to the Ruby On Rails framework with conventions such as "id" for the primary key for each table. Also the relationships are all simple one_to_many's with no many_to_many or has_many throughs needed. I would probably add has_many :throughs and/or :delegates though to get things like survey_name from an individual answer easily without.multiple.chaining.
You could also think about complex rules, and have a string based condition field in your Questions table, accepting/parsing any of these:
A(1)=3
( (A(1)=3) and (A(2)=4) )
A(3)>2
(A(3)=1) and (A(17)!=2) and C(1)
Where A(x)=y means "Answer of question x is y" and C(x) means the condition of question x (default is true)...
The questions have an order field, and you would go through them one-by one, skipping questions where the condition is FALSE.
This should allow surveys of any complexity you want, your GUI could automatically create these in "Simple mode" and allow for and "Advanced mode" where a user can enter the equations directly.
one way is to add a table 'question requirements' with fields:
question_id (link to the "which brand?" question)
required_question_id (link to the "do you smoke?" question)
required_answer_id (link to the "yes" answer)
In the application you check this table before you pose a certain question.
With a seperate table, it's easy adding required answers (adding another row for the "sometimes" answer etc...)
Personally, in this case, I would use the structure you described and use the database as a dumb storage mechanism. I'm fan of putting these complex and dependend constraints into the application layer.
I think the only way to enforce these constraints without building new tables for every question with foreign keys to others, is to use the T-SQL stuff or other vendor specific mechanisms to build database triggers to enforce these constraints.
At an application level you got so much more possibilities and it is easier to port, so I would prefer that option.
I hope this will help you in finding a strategy for your app.