Is there a quick and easy way to make a VB.NET user interface for managing the data in a normalized DataSet?
I know that is a very subjective question, so let me explain. For a brief period early in my career, I used to create user interfaces in Microsoft Access. I developed a simple, but very effective approach to user interface design. Here are some details of that approach:
Create one form per table. Put on
each form all controls necessary to
completely manage one row in the
table.
Use combo boxes for
foreign-key columns.
Give the user a
standard way to add rows and delete
rows.
Use Apply and Undo buttons.
Let
the user navigate from one row to
another with a list box.
Provide a
search box and filter options for
more efficient navigation.
Let the
user double-click on controls
representing foreign-key columns to
quickly navigate from one form to
another.
Make the state of each form
persistent (so the user always
returns to the last navigation point)
etc.
Simple, right? I found that Access encouraged this approach. It has many built-in features that make this kind of UI easy. For instance, creating a combo box to represent a foreign key relationship takes about 10 seconds.
Well, I haven't worked in Access for a while. A couple of years ago, however, I was hired to write an application in VB.NET on the NET 2.0 framework. To get a data management user interface up and running quickly, I used my Access experience to write a quick & easy prototype in Access -- that took me about one week. Then I hired a programmer to implement that same UI in VB.NET. What a nightmare! We've been working on that implementation for a year, and I'm still very unsatisfied with the results. Some of the problems we are having:
Apply and Undo buttons don't work quite right. We can't find an event that tells us when the form is "dirty" (thus making Apply and Undo relevant).
Navigation from row to row and from form to form requires surprisingly complicated code. I get the impression that we are fighting against NET's binding features, not working with them the way they were intended to be used.
The NET controls seem buggy. For instance, when the user types a value into a combo box (as opposed to choosing it from the drop down), it doesn't trigger the SelectedValueChanged event.
We seem to be repeating a lot of information. For instance, the DataSet knows there is a relationship between the columns in two tables, but we must nevertheless effectively repeat the details of that relationship when we program the combo boxes, binding, navigtation features, etc.
We still don't have good solutions for the filter and search features. There are lots of little details to work out. (For instance, what if you choose a filter that doesn't include the currently displayed row?)
We are writing many helper functions and classes to simplify the work, and I can't figure out why that effort hasn't already been done by others -- I'm certain we are reinventing the wheel.
etc.
By themselves, none of the above are a big deal -- there are effective solutions to each one. Taken together, however, these problems are making my UI development go much slower than expected.
In an ideal world, I should be able to create a small amount of code relevant to my specific data model (for instance, one user control per table establishing the layout and logic relevant to the rows in that table) then integrate that code into a template which interprets the data model and handles everything else -- navigation, adding and deleting, apply and undo, search and filter, etc.
Thus, my question: Is there anything out there which makes this type of UI development easier?
I've searched the web for various combinations of "generic forms", "UI templates", "data managment forms", etc., but I haven't found anything on topic. Perhaps I just don't know the buzzwords. Is there a specific name for this type of UI development task?
Create UCs for each table. Drop a grid control onto the UC and bind it to the tables dataset using VS's wizard. Select the options that allow for insert, update, delete. Each row on the grid will have those buttons/actions automatically added for you.
Related
I'm trying to figure out how to determine the best balance in structuring a database. I want to be able to store the information from several different forms submitted by different people, sometimes multiple times (such as a yearly update). I'm stuck between having a different table for each form, or a combination of form and element definition and element value tables.
Example A: There are three types of form with different information, so there are four tables, [FormA], [FormB], and [FormC] that each have the data associated with their respective forms, all FKed to [Customers].
Example B: Same three forms, but this time there are five different tables. [FormDescriptions] defines the form names, types, etc and has three entries, one for each form. [Forms] FKs to [Customers] and [FormDescriptions] and uses these in combination with the submission date to distinguish individual submissions. [FormElements] defines all the elements from the three forms, with a FK on FormDescriptions and a unique elementID. [ElementValues] FKs to [FormElements] and [Forms] and stores the value of the selected element on the selected form.
My question is, is one of these methods inherently better than the other, and if not, in which situations is each better than the other? As much why or why not that you want to include is appreciated.
"My question is, is one of these methods inherently better than the other, and if not, in which situations is each better than the other? As much why or why not that you want to include is appreciated."
Your option two is (your personalized variant of) the EAV antipattern. If you use this, and you expect (now or later) the system to do anything "intelligent" with the data, you'll find yourself in serious trouble. And things as basic as "rigorous data validation to catch data entry errors" already qualifies as "intelligent". So only use it if you can reasonably anticipate that the system will only be used for just merely storing the data, and that it will be unlikely for there ever to be a request to start processing/manipulating the data in "intelligent ways".
If you ever run into requests to start doing "intelligent" things with an EAV database, you'll find that whatever development time you thought you gained by working from a super duper generic information model, you'll lose orders of magnitude more time coding all the "intelligent" things required, i.e. reinstating the data structures in code that you refused to reflect in the DB.
Googling for "EAV antipattern" (try to locate the book by Bill Karwin) should provide you with more than enough info on why not to do it.
There are 2 factors in consideration here
Performance
flexibility
If your system is such that it will require you to add more forms in future frequently.. method 2 is better. You won't have to add additional tables or columns. Your forms are data driven. It will add little overhead for generating forms and saving as key value pairs.
On other hand if your system won't require many changes to forms first method can work.
Also consider usage of data after forms are submitted. Are you going to run analytics, reports on this data? Are these reports specific to forms? That will favor method 1.
I have an application that allows the user to drill down through data from a single large table with many columns. It works like this:
There is a list of distinct top-level table values on the screen.
User clicks on it, then the list changes to the distinct next-level values for whatever was clicked on.
User clicks on one of those values, taken to 3rd level values, etc.
There are about 50 attributes they could go through, but it usually ends up only being 3 or 4. But since those 3 or 4 vary among the 50 possible attributes, I have to persist the selections to the browser. Right now I do it in a hideous and bulky hidden form. It works, but it is delicate and suboptimal. In order for it to work, the value of whatever level attribute is on the screen is populated in the appropriate place on the hidden form on the click event, and then a jQuery Ajax POST submits the form. Ugly.
I have also looked at Backbone.js, but I don't want to roll another toolkit into this project while there may be some other simple convention that I'm missing. Is there a standard Rails Way of doing something like this, or just some better way period?
Possible Approaches to Single-Table Drill-Down
If you want to perform column selections from a single table with a large set of columns, there are a few basic approaches you might consider.
Use a client-side JavaScript library to display/hide columns on demand. For example, you might use DataTables to dynamically adjust which columns are displayed based on what's relevant to the last value (or set of values) selected.
You can use a form in your views to pass relevant columns names into the session or the params hash, and inspect those values for what columns to render in the view when drilling down to the next level.
Your next server-side request could include a list of columns of interest, and your controller could use those column names to build a custom query using SELECT or #pluck. Such queries often involve tainted objects, so sanitize that input thoroughly and handle with care!
If your database supports views, users could select pre-defined or dynamic views from the next controller action, which may or may not be more performant. It's at least an idea worth pursuing, but you'd have to benchmark this carefully, and make sure you don't end up with SQL injections or an unmanageable number of pre-defined views to maintain.
Some Caveats
There are generally trade-offs between memory and latency when deciding whether to handle this sort of feature client-side or server-side. It's also generally worth revisiting the business logic behind having a huge denormalized table, and investigating whether the problem domain can't be broken down into a more manageable set of RESTful resources.
Another thing to consider is that Rails won't stop you from doing things that violate the basic resource-oriented MVC pattern. From your question, there is an implied assumption that you don't have a canonical representation for each data resource; approaching Rails this way often increases complexity. If that complexity is truly necessary to meet your application's requirements then that's fine, but I'd certainly recommend carefully assessing your fundamental design goals to see if the functional trade-offs and long-term maintenance burdens are worth it.
I've found questions similar to yours on Stack Overflow; there doesn't appear to be an API or style anyone mentions for persisting across requests. The best you can do seems to be storage in classes or some iteration on what you're already doing:
1) Persistence in memory between sessions/requests
2) Coping with request persistence design-wise
3) Using class caching
What is the best practice for having many different menus/screens/forms in a visual basic program? Would it be to just make a new form for each menu or screen that I want? Or are there other better options?
I am not trying to make this overly complicated, I have a group project to work on and we all have different skill levels. That said it has peaked my curiosity so I figured it wouldn't hurt to ask before I got started.
I can see this question being closed pretty quickly as being too open ended so allow me to get in my key gripe on this before that happens... no .Visible property for TabControl pages? Seriously, Microsoft??
Which brings me to the key point. If the forms are in some way related but not necessarily identical I prefer to use a single form with different tabs, despite that glaring shortcoming in the control. (Which you don't have to look far to find workarounds for on SO, but a workaround is still a workaround.) Dynamically manipulating controls at run time is another side of this coin, though one that I tend to use more rarely... but that's just a personal thing.
In a recent application, for instance, I had lists of several types of objects. They were related, but performed quite different functions and the user wouldn't really need to look at more than one list at once. As a result I used one form with a tab for each object list to keep the users' display less cluttered.
Similarly when doing a GL app recently I had the journal header and journal line entries (which go to different tables in the back-end database) in separate parts of the one form. On the other hand asset creation was sufficiently different that I created a different form, despite the creation process sharing some of the underlying data. (That is, journal line data.)
I don't believe in the concept of "best practice" because what's a good practice in one situation may be a very bad one in another. However the "rules of thumb" that I use are:
- Keep the number of forms to a minimum to keep overhead low and reduce maintenance BUT
- If there is no logical "tie" between two functions, don't be afraid to make a new form because trying to maintain one form which performs 7 different roles is a guaranteed path to madness and frustration, especially if you break something inadvertently.
Yes, the two rules conflict, but in a way I see this aspect of design as being akin to database normalisation; there's a sweet spot between over-normalising (a separate form for each and every display) and under-normalising (trying to shoe-horn too many unrelated functions into one form). At the very least the rules always give me pause to think "do I need this form, or does it relate to something that I've already done?"
And the third rule of thumb is, obviously... always look at it from the point of view of your user. Are they going to feel like you're bouncing them around too much? Do all of the forms share a look and feel and, more importantly, control layout so that they always know where to find something?
All of these things will vary from app to app, and there's never one size that will fit all IMHO.
In my case, when I am dealing with multiple forms, I use MDI Parent Form to avoid multiple items in the windows task bar.
Another unusual solution is to set each forms ShowInTaskbar property to false.
I'm interested in displaying 1-5 model instances using forms on a page using a grid similar to something one would find in a desktop database application. I understand I would need to use multiple forms or formsets but an additional requirement is that I'd prefer it to be in more of a grid format with each model's fields being display in columns with common field labels on the y-axis.
I should have the ability to edit multiple columns (so in effect, model instances) at the same time and then commit either the single column (model instance) or commit all. I'd also like to be able to highlight the changed cells that have changed to give visual feedback to the user that there are pending changes.
Sorry for the rather long list of requirements and I'm aware this probably requires a few different technologies/techniques to achieve. I'm throwing this out there because I'm asking this kind community for guidance on what components/technologies I should look at. If luck would have it, there would be some jQuery component that can handle this for me almost out of the box. If not, some guidance on achieving the editing of multiple model instances would be of help.
I will also need to build in versioning in case the data displayed on the view page is stale and to prevent overwriting a newer commit. I'd probably achieve the latter using a versioning field in the table that will perform the check and handle it accordingly.
Also, Flask and Django are both options for the engine and WTForms look to be promising at least at first look.
Thanks
There is no such ready to use solution in Django. Just create your custom form that handles as many instances as you want and do anything that you want, or extend formset.
How would you create a database in Microsoft Access that is searchable only by certain fields and controlled by only a few (necessary) text boxes and check boxes on a form so it is easy to use - no difficult queries?
Example:
You have several text boxes and several corresponding check boxes on a form, and when the check box next to the text box is checked, the text box is enabled and you can then search by what is entered into said text box
(Actually I already know this, just playing stackoverflow jeopardy, where I ask a question I know the answer just to increase the world's coding knowledge! answer coming in about 5 mins)
My own solution is to add a "filter" control in the header part of the form for each of the columns I want to be able to filter on (usually all ...). Each time such a "filter" control is updated, a procedure will run to update the active filter of the form, using the "BuildCriteria" function available in Access VBA.
Thus, When I type "*cable*" in the "filter" at the top of the Purchase Order Description column, the "WHERE PODescription IS LIKE "*cable*" is automatically added to the MyForm.filter property ....
Some would object that filtering record source made of multiple underlying tables can become very tricky. That's right. So the best solution is according to me to always (I mean it!) use a flat table or a view ("SELECT" query in Access) as a record source for a form. This will make your life a lot easier!
Once you're convinced of this, you can even think of a small module that will automate the addition of "filter" controls and related procedures to your forms. You'll be on the right way for a real user-friendly client interface.
This is actually a pretty large topic, and fraught with all kinds of potential problems. Most intermediate to advanced books on Access will have some kind of section discussing "Query by Form," where you have an unbound form that allows the user to choose certain criteria, and that when executed, writes on-the-fly SQL to return the matching data.
In anything but a flat, single-table data structure, this is not a trivial task because the FROM clause of the SQL is dependent on the tables queried in the WHERE clause.
A few examples of some QBF forms from apps I've created for clients:
Querying 4 underlying tables
Querying a flat single table
Querying 3 underlying tables
Querying 6 underlying tables
Querying 2 underlying tables
The first one is driven by a class module that has properties that reflect the criteria selected in this form, and that has methods that write the FROM and WHERE clauses. This makes it extremely easy to add other fields (as long as those fields don't come from tables other than the ones already included).
The most complex part of the process is writing the FROM clause, as you have to have appropriate join types and include only the tables that are either in the SELECT clause or the WHERE clause. If you include anything else, you'll slow down your query a lot (especially if you have any outer joins).
But this is a big subject, and there is no magic bullet solution -- instead, something like this has to be created for each particular application. It's also important that you test it thoroughly with users, since what is completely clear and understandable to you, the developer, is often pretty darned mystifying to end users.
But that's a principle that doesn't just apply to QBF!
At start-up, you need to show a form and disable other menus etc. That way your user only ever sees your limited functionality and cannot directly open the tables etc.
This book excerpt, Real World Microsoft Access Database Protection and Security, should be enlightening.
For a question that vague, all that I can answer is open MS Access, and click the mouse a few times.
On second thought:
Use the "WhereCondition" argument of the "OpenForm" method
If the functionality is very limited and/or specialised then a SQL database is probably going to be overkill anyhow e.g. cache all combinations of the data locally, in memory even, and show one according to the checkboxes on the form. Previously you could have revoked permissions from the table and granted them only on VIEWs/PROCs that queried the data in the prescribed way, however security has been removed from MS Access 2007 so you can you now really stop users bypassing your simple app using, say, Excel and querying the data any way they like ...but then isn't that the point of an enterprise database? ;-)