Ok so this is my first question on this site so please bear with me.
My problem is that our company is currently changing from access to an SQL database back end and I was given the job to design a front-end for non programmer users to just pull pre-defined queries or build a query of their own by just selecting the fields they want (dynamic query).
What I want to know is what would be the simplest way to go about doing this due to the fact that I have a some programming background but I wouldn't say I'm an advanced programmer.
I've done some searching over the last couple days and came across things such as Ruby on Rails and phpMyAdmin however before I take on the task of learning how to program with these tools I want to know for sure if I am going in the right direction before wasting my time on a pointless endeavor.
I've seen similar questions even on this site however none truly gave the answer I was looking for; any help will be much appreciated.
Also would it be easier to make this web-based?
Related
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.
Is there a table on MS SQL 2005 or 2008 servers that will show my boss how much work I'm doing?
Maybe something that would show how often my database tables/views/etc are being executed/queried against?
I would probably look at setting up a trace. You can read up on Data Access Tracing here.
Once you are done doing that, write a script that makes it look like you are working 24 hours a day and ask for a raise. Seriously if your boss is using your query history to determine how much work you are doing he is:
A real ball buster
Clueless
Get Mladen Prajdic's SSMS Tools Pack. It can keep a running history (in a database, on the local file system, or on a network share IIRC) of queries you are working on and/or executing, and you can customize how often it auto-saves for you. It won't tell you how much time you spent staring at the screen between edits or reviewing query results, but it should be a start.
Short answer: No.
There is nothing built in and immediatley avaliable within SQL Server that does this. There are any number of ways such functionality can be implemented, but none are simple or trivial, and a skilled DBA could run rings around 'em anyway.
This is what I use for looking up on what I have done during the day. This will be applicable to you ONLY if the the window title of whatever software, changes depending on what you are currently working on.
Eg: My Awesome SQL Software - Query1.sql
My Awesome SQL Software - newQuery.sql
My Awesome SQL Software - Results of Table 1
Manic Time will track individual applications + their window title.
http://www.manictime.com/
I have some pretty complex reports to write. Some of them... I'm not sure how I could write an sql query for just one of the values, let alone stuff them in a single query.
Is it common to just pull a crap load of data and figure it all via code instead? Or should I try and find a way to make all the reports rely on sql?
I have a very rich domain model. In fact, parts of code can be expanded on to calculate exactly what they want. The actual logic is not all that difficult to write - and it's nicer to work my domain model than with SQL. With SQL, writing the business logic, refactoring it, testing it and putting it version control is a royal pain because it's separate from your actual code.
For example, one the statistics they want is the % of how much they improved, especially in relation to other people in the same class, the same school, and compared to other schools. This requires some pretty detailed analysis of how they performed in the past to their latest information, as well as doing a calculation for the groups you are comparing against as a whole. I can't even imagine what the sql query would even look like.
The thing is, this % improvement is not a column in the database - it involves a big calculation in of itself by analyzing all the live data in real-time. There is no way to cache this data in a column as doing this calculation for every row it's needed every time the student does something is CRAZY.
I'm a little afraid about pulling out hundreds upon hundreds of records to get these numbers though. I may have to pull out that many just to figure out 1 value for 1 user... and if they want a report for all the users on a single screen, it's going to basically take analyzing the entire database. And that's just 1 column of values of many columns that they want on the report!
Basically, the report they want is a massive performance hog no matter what method I choose to write it.
Anyway, I'd like to ask you what kind of solutions you've used to these kind of a problems.
Sometimes a report can be generated by a single query. Sometimes some procedural code has to be written. And sometimes, even though a single query CAN be used, it's much better/faster/clearer to write a bit of procedural code.
Case in point - another developer at work wrote a report that used a single query. That query was amazing - turned a table sideways, did some amazing summation stuff - and may well have piped the output through hyperspace - truly a work of art. I couldn't have even conceived of doing something like that and learned a lot just from readying through it. It's only problem was that it took 45 minutes to run and brought the system to its knees in the process. I loved that query...but in the end...I admit it - I killed it. ((sob!)) I dismembered it with a chainsaw while humming "Highway To Hell"! I...I wrote a little procedural code to cover my tracks and...nobody noticed. I'd like to say I was sorry, but...in the end the job ran in 30 seconds. Oh, sure, it's easy enough to say "But performance matters, y'know"...but...I loved that query... ((sniffle...)) Anybody seen my chainsaw..? >;->
The point of the above is "Make Things As Simple As You Can, But No Simpler". If you find yourself with a query that covers three pages (I loved that query, but...) maybe it's trying to tell you something. A much simpler query and some procedural code may take up about the same space, page-wise, but could possibly be much easier to understand and maintain.
Share and enjoy.
Sounds like a challenging task you have ahead of you. I don't know all the details, but I think I would go at it from several directions:
Prioritize: You should try to negotiate with the "customer" and prioritize functionality. Chances are not everything is equally useful for them.
Manage expectations: If they have unrealistic expectations then tell them so in a nice way.
IMHO SQL is good in many respects, but it's not a brilliant programming language. So I'd rather just do calculations in the application rather than in the database.
I think I'd go for some delay in the system .. perhaps by caching calculated results for some minutes before recalculating. This is with a mind towards performance.
The short answer: for analysing large quantities of data, a SQL database is probably the best tool around.
However, that does not mean you should analyse this straight off your production database. I suggest you look into Datawarehousing.
For a one-off report, I'll write the code to produce it in whatever I can best reason about it in.
For a report that'll be generated more than once, I'll check on who is going to be producing it the next time. I'll still write the code in whatever I can best reason about it in, but I might add something to make it more attractive to use to that other person.
People usually use a third party report writing system rather than writing SQL. As an application developer, if you're spending a lot of time writing complex reports, I would severely question your manager's actions in NOT buying an off-the-shelf solution and letting less-skilled people build their own reports using some GUI.
I have been working on sql server and front end coding and have usually faced problem formulating queries.
I do understand most of the concepts of sql that are needed in formulating queries but whenever some new functionality comes into the picture that can be dont using sql query, i do usually fails resolving them.
I am very comfortable with select queries using joins and all such things but when it comes to DML operation i usually fails
For every query that i never done before I usually finds uncomfortable with that while creating them. Whenever I goes for an interview I usually faces this problem.
Is it their some concept behind approaching on formulating sql queries.
Eg.
I need to create an sql query such that
A table contain single column having duplicate record. I need to remove duplicate records.
I know i can find the solution to this query very easily on Googling, but I want to know how everyone comes to the desired result.
Is it something like Practice Makes Man Perfect i.e. once you did it, next time you will be able to formulate or their is some logic or concept behind.
I could have get my answer of solving above problem simply by posting it on stackoverflow and i would have been with an answer within 5 to 10 minutes but I want to know the reason. How do you work on any new kind of query. Is it a major contribution of experience or some an implementation of concepts.
Whenever I learns some new thing in coding section I tries to utilize it wherever I can use it. But here scenario seems to be changed because might be i am lagging in some concepts.
EDIT
How could I test my knowledge and
concepts in Sql and related sql
queries ?
Typically, the first time you need to open a child proof bottle of pills, you have a hard time, but after that you are prepared for what it might/will entail.
So it is with programming (me thinks).
You find problems, research best practices, and beat your head against a couple of rocks, but in the process you will come to have a handy set of tools.
Also, reading what others tried/did, is a good way to avoid major obsticles.
All in all, with a lot of practice/coding, you will see patterns quicker, and learn to notice where to make use of what tool.
I have a somewhat methodical method of constructing queries in general, and it is something I use elsewhere with any problem solving I need to do.
The first step is ALWAYS listing out any bits of information I have in a request. Information is essentially anything that tells me something about something.
A table contain single column having
duplicate record. I need to remove
duplicate
I have a table (I'll call it table1)
I have a
column on table table1 (I'll call it col1)
I have
duplicates in col1 on table table1
I need to remove
duplicates.
The next step of my query construction is identifying the action I'll take from the information I have.
I'll look for certain keywords (e.g. remove, create, edit, show, etc...) along with the standard insert, update, delete to determine the action.
In the example this would be DELETE because of remove.
The next step is isolation.
Asnwer the question "the action determined above should only be valid for ______..?" This part is almost always the most difficult part of constructing any query because it's usually abstract.
In the above example you're listing "duplicate records" as a piece of information, but that's really an abstract concept of something (anything where a specific value is not unique in usage).
Isolation is also where I test my action using a SELECT statement.
Every new query I run gets thrown through a select first!
The next step is execution, or essentially the "how do I get this done" part of a request.
A lot of times you'll figure the how out during the isolation step, but in some instances (yours included) how you isolate something, and how you fix it is not the same thing.
Showing duplicated values is different than removing a specific duplicate.
The last step is implementation. This is just where I take everything and make the query...
Summing it all up... for me to construct a query I'll pick out all information that I have in the request. Using the information I'll figure out what I need to do (the action), and what I need to do it on (isolation). Once I know what I need to do with what I figure out the execution.
Every single time I'm starting a new "query" I'll run it through these general steps to get an idea for what I'm going to do at an abstract level.
For specific implementations of an actual request you'll have to have some knowledge (or access to google) to go further than this.
Kris
I think in the same way I cook dinner. I have some ingredients (tables, columns etc.), some cooking methods (SELECT, UPDATE, INSERT, GROUP BY etc.) then I put them together in the way I know how.
Sometimes I will do something weird and find it tastes horrible, or that it is amazing.
Occasionally I will pick up new recipes from the internet or friends, then use parts of these in my own.
I also save my recipes in handy repositories, broken down into reusable chunks.
On the "Delete a duplicate" example, I'd come to the result by googling it. This scenario is so rare if the DB is designed properly that I wouldn't bother keeping this information in my head. Why bother, when there is a good resource is available for me to look it up when I need it?
For other queries, it really is practice makes perfect.
Over time, you get to remember frequently used patterns just because they ARE frequently used. Rare cases should be kept in a reference material. I've simply got too much other stuff to remember.
Find a good documentation to your software. I am using Mysql a lot and Mysql has excellent documentation site with decent search function so you get many answers just by reading docs. If you do NOT get your answer at least you are learning something.
Than I set up an example database (or use the one I am working on) and gradually build my SQL. I tend to separate the problem into small pieces and solve it step by step - this is very successful if you are building queries including many JOINS - it is best to start with some particular case and "polute" your SQL with many conditions like WHEN id = "123" which you are taking out as you are working towards your solution.
The best and fastest way to learn good SQL is to work with someone else, preferably someone who knows more than you, but it is not necessarry condition. It can be replaced by studying mature code written by others.
Your example is a test of how well you understand the DISTINCT keyword and the GROUP BY clause, which are SQL's ways of dealing with duplicate data.
Examples and experience. You look at other peoples examples and you create your own code and once it groks, you don't need to think about it again.
I would have a look at the Mere Mortals book - I think it's the one by Hernandez. I remember that when I first started seriously with SQL Server 6.5, moving from manual ISAM databases and Access database systems using VB4, that it was difficult to understand the syntax, the joins and the declarative style. And the SQL queries, while powerful, were very intimidating to understand - because typically, I was looking at generated code in Microsoft Access.
However, once I had developed a relatively systematic approach to building queries in a consistent and straightforward fashion, my skills and confidence quickly moved forward.
From seeing your responses you have two options.
Have a copy of the specification for whatever your working on (SQL spec and the documentation for the SQL implementation (SQLite, SQL Server etc..)
Use Google, SO, Books, etc.. as a resource to find answers.
You can't formulate an answer to a problem without doing one of the above. The first option is to become well versed into the capabilities of whatever you are working on.
The second option allows you to find answers that you may not even fully know how to ask. You example is fairly simplistic, so if you read the spec/implementation documentaion you would know the answer right away. But there are times, where even if you read the spec/documentation you don't know the answer. You only know that it IS possible, just not how to do it.
Remember that as far as jobs and supervisors go, being able to resolve a problem is important, but the faster you can do it the better which can often be done with option 2.
I'm trying to implement a search feature for an offline-accessible StackOverflow, and I'm noticing some problems with using MySQLs FULLTEXT indexing.
Specifically, by default FULLTEXT indexing is restricted to words between 4 and 84 characters long. Terms such as "PHP" or "SQL" would not meet the minimum length and searching for those terms would yield no results.
It is possible to modify the variable which controls the minimum length a word needs to be to be indexed (ft_min_word_len), but this is a system-wide change requiring indexes in all databases to be rebuilt. On the off chance others find this app useful, I'd rather keep these sort of variables as vanilla as possible. I found a post on this site the other day stating that changing that value is just a bad idea anyway.
Another issue is with terms like "VB.NET" where, as far as I can tell, the period in the middle of the term separates it into two indexed values - VB and NET. Again, this means searches for "VB.NET" would return nothing.
Finally, since I'm doing a direct dump of the monthly XML-based dumps, all values are converted to HTML Entities and I'm concerned that this might have an impact on my search results.
I found a blog post which tries to address these issues with the following advice:
keep two copies of your data - one with markup, etc. for display, and one modified for searching (remove unwanted words, markup, etc)
pad short terms so they will be indexed, I assume with a pre/suffix.
What I'd like to know is, are these really the best workarounds for these issues? It seems like semi-duplicating a > 1GB table is wasteful, but maybe that's just me.
Also, if anyone could recommend a good site to understand MySQL's FULLTEXT indexing, I'd appreciate it. To keep this question from being too cluttered, please leave the site recommendations in the question comments, or email me directly at the site on my user profile).
Thanks!
Additional Info:
I think I should clarify a couple of things.
I know "MySQL" tends to lead to the assumption of "web application", but that's not what I'm going for here. I could install Apache and PHP and run things that way, but I'm trying to keep this light. I can use my website for playing with PHP, so I don't feel the need to install it on my home machine too. I also hope this could be useful for others as well, and I don't want to force anyone else into installing a bunch of extra utilities. I went with MySQL since it was easy and needing to install some sort of DB was unavoidable.
The specifics of the project were going to be:
Desktop application written in C# (WinForms)
MySQL backend
I'm starting to wonder if I should just say to hell with it, and install everything I'd need to make this an (offline) webapp. As much as we'd all like to think our pet project is going to be used and loved by the community at large, I should know by now that this is likely going end up being only used by a single user.
From what was already said, I understand, that MySQL FullText is not for you ;) But why stick to MySQL? Try Sphinx:
http://www.sphinxsearch.com/
It will solve most of your problems.