I am building an mvc 3 application that will be multi-tenant, which means it will use the same basic data structure, but provide different data depending on the domain name used to access it.
A problem I am trying to solve is this. How best do I populate a number of dropdown lists with selection choices based on the site being rendered. To add another wrinkle, I will need to localize the strings as well.
An obvious choice is to simply create a table with columns for website id and language id, plus field id and string value. This seems ok, but also seems to ignore possible mechanisms that are already in place for localization. I feel like i'm recreating the wheel here.
As an example, site 1 might have a dropdownlist for Favorite Activities, and have ranges items that are geared toward musical interests. Site 2 might have the same dropdown, but have items geared for sports intersts.
So my question is, how would you go about solving this problem? Also, in a similar vein... If you have selection lists, say State codes, cities, etc.. would you tend to create seperate tables to populate this data (states table, cities table, etc..) or would you put all this information in a common table and have an ID to indicate which dropdown it was to be used for? The former seems more normalized, but the latter seems more efficient (less code to write).
Thoughts about Common Lookup Tables. This guy is definitely against.
http://www.projectdmx.com/dbdesign/lookup.aspx
I have used it and believe that I have saved some time, or at least some keystrokes. Might be sorry later on.
Related
I am making a user form in Delphi for documents tracking application. I am interested in functionalities input new entry (record) and view list by... (date, name of document, ID,...).
My problem is that I don't know how to implement these functionalities for more than one user. Currently, I have 5 users. Each user has a unique input data (record) fields (columns) and view fields (columns) of each user are also unique. There could be more users.
So, how to implement these functionalities for this form? How to assign different data (fields) for each separate user for input and view? That is what I don't understand. Is that distributed functionality of an application? If yes, how to achieve it?
Note that I don't want static assigning of a user in application's code, e.g:
if(username='user1') then {
input();
view();
}
else if (username='user2') then {...}
...
because, than, every time there is a new user, developer must go back to the application's code and hard-code it. That is not efficient and is a bad implementation. Rather, I want that to be dynamic (if that is the right term). How to achieve this?
Note: I am using dbExpress tool with MySQL DBMS with RAD Studio XE7 Architect.
If I'm correctly understanding what you are asking, it seems as if you are unfamiliar with the idea of tables/datasets which operate in a so-called Master-Detail relationship. These are very easy to set up in Delphi.
Once you get familar with M->D relationships, I think you'll realise that what you should have been asking about is how to set one up in your app, rather than the problem of hard-coding of individual users into your form.
In your case, what you are missing at the moment is a table of users' details. Let's call that the Users table. Usually this would contain their name, obviously, and some kind of unique identifier (best is a "Primary key" in the Users database table), but NOT, please, their password to access the db, especially not in plain text.
Once your Users table is created, you can create a display grid (TDBGrid) and input/editing form for it.
Then, if you don't have it already, you could set up a grid and editing form for users' documents (which I'm going to refer to as the Documents table).
Once that's done, the main thing left to do is to set up in your Delphi project a Master-Detail relationship between your Users table (the master) and your Documents table (the detail).
If you prefer you can have a single form with two grids, the Users grid and the Documents grid on it, and as you scroll through the Users grid, you'll see that the Documents grid shows only their document records.
The details of how to set up a Master-Detail vary somewhat according to the type of table/dataset you're using so you'll need to search online for the details of how to do it. Broadly, it's a matter of connecting a TDataSource to your Users table and setting the DataSource (or MasterSource) property of your Documents table to point at the Users TDataSource, and then setting a couple of other, table-type-dependent properties of the Documents table.
Every edition of Delphi since well before D7 has come with a demo app, "MastApp" which illustrates how you use Master-Detail relationship amongst a number of tables. I suggest you take a look at the MastApp for your Delphi version and then look into how to set up M->D relationships for the type of Delphi dataset you are actually using.
First of all, I want to apologize for my terminology. I am not entirely sure what to call what I am looking for, so I can’t google for answers. But here is my problem.
I am working on a Rails application that stores information about different websites and provides various services for them. I will call these services ‘Products.’ One website can be subscribed to several products, and a product can be served to various websites. So here is a very simple association scheme for these relationships:
At least, it would have been simple, but the problem is that the Settings model (shown in red on this diagram) is different for each product: for one product, it will have one number of fields and data types, for another it will have a different number of fields with different data types. On the other hand, the Faq and Description are the same, so if I redraw the diagram as follows:
I will get another problem: too much repetition (shown in blue on the diagram). Ideally, I want some kind of modification of the first diagram, where the Product model will choose differens Settings models depending on a parameter that I pass to it:
So that a request website.products.find(1).settings will return the model Settings1, while a request website.products.find(2).settings will return a completely different model, Settings2.
Is this achievable in Rails? If not, how would you organize such data?
I'm have application that allows users to store food diary entries of approximately 140 characters in length. I am looking for a solution that will allow me to tie content modules (think tips for healthy eating) to the user's diary entries based on keywords in the entry similar to what Google does with adwords. Are there any out-of-the-box solutions that can do that in Rails?
Here are the specific requirements:
User logs food diary entry
In the user's food diary, if there's a specific tip that matches a keyword for the entry, then the tip is displayed next to the entry
Tips would be defined through an admin tool where the admin specifies the tip content and keywords that would make it appear in the diary
Trying to figure out a) if there's a pre-build solution I could use for something like this or b) what the best approach would be for performance since the users's food diary might have 20 entries per page, and each entry would have to be evaluated to see if there are any corresponding tips that match entry keywords.
For designing a home-grown solution, one idea I had was to make the tip associations when a new food entry is stored like this:
user adds a food entry
after_save a callback method breaks apart the entry into keywords and searches the tips model for matches
if there's a match, it's stored in an association table when new entries are created rather then when the user's food diary is rendered in the web page.
There's a performance hit on storing new entries, but it might allow the user's diary to load faster then doing all those look-ups when the diary is rendered.
Does that make sense, or is there a better way? better yet, are there tools that can accomplish what I'm trying to do?
Thanks!
This is not an AdWords API question, but I'll take a shot:
I would move the association table building into an offline task / cronjob. That would take care of the performance overhead when creating new entries, and users would be generally okay with a message like "Tips are being generated, please be patient" if they happen to view the topic too soon.
I'm not aware of any existing solutions, but this sounds like a hashtag system to me. Basically you have two lists (food dairy entries, tips), you want to assign hashtags to both lists and then pair entries with same hashtags. Googling for a hashtag system / library might be a good starting point.
Cheers,
Anash
I just started to develop an invoice app. I would like to hear your opinions and recommendations about this dilemma.
The invoice has a client section. The client can be selected from a drop-down select menu or it can be entered directly into a text field. Let's say it's just a one time purchase and the client won't ever come back. Should I have these two columns: client_id and client_field so either of those two can be filled out? The negative side is that a lot of client_field will be empty. Or should I not use a client_field and just add a new client even thought that client will only be used once?
Be consistent and use a separate client model and client_id even for clients that only appear once. If you have both client_id and client_model you will have extra complexity:
Your validation will have to check both and ensure that everything is consistent.
You will have to o.client.try(:name) || o.client_field and such all over the place just to display data.
If you change the structure of your client records in the future you will have to reformat your "table within a table" client_field kludge.
Any database based reporting will go from simple SQL to a monstrosity of LEFT JOINs and CASE statements.
And those are just a couple things off the top of my head.
If you're worried about having a dropdown with a lot of entries — and you should be worried about any dropdown with more than ~20 entries — then go with just an autocompleting text input or limit the dropdown to the top ~20 clients and use a autocompleting text input for the rest (or perhaps even a JavaScript based combo-box); there's a good chance that the dropdown won't even get used by your users, accountants and other people that do a lot of data entry and invoicing often hate having to reach for the mouse.
Is there anything wrong with having an auto-complete field where, if submitted without a matching ID, you will just create the client and link them in?
That's what's expected from the stand-point of the user and it's how applications like QuickBooks have worked for years.
I'm learning Rails by building a simple site where users can create articles and comment on those articles. I have a view which lists a user's most recent articles and comments. Now I'd like to add user 'profiles' where users can enter information like their location, age and a short biography. I'm wondering if this profile should be a separate model/resource (I already have quite a lot of fields in my user model because I'm using Authlogic and most of it's optional fields).
What are the pros and cons of using a separate resource?
I'd recommend keeping profile columns in the User model for clarity and simplicity. If you find that you're only using certain fields, only select the columns you need using :select.
If you later find that you need a separate table for some reason (e.g. one user can have multiple profiles) it shouldn't be a lot of work to split them out.
I've made the mistake of having two tables and it didn't buy me anything but additional complexity.
Pros: It simplifies each model
Cons: Managing 2 at once is slightly harder
It basically comes down to how big the user and profile are. If the user is 5 fields, and the profile 3, there is no point. But if the user is 12 fields, and the profile 20, then you definitely should.
I think you'd be best served putting in a separate model. Think about how the models correspond to database tables, and then how you read those for the various use cases your app supports.
If a user only dips in to his actual profile once in a while but the User model is accessed frequently, you should definitely make it a separate object with a one-to-one relationship. If the profile data is needed every time the User data is needed, you might want to stick them in the same table.
Maybe the location is needed every time you display the user (say on a comment they left), but the biography should be a different model? You'll have to figure out the right breakdown, but the general rule is to structure things so you don't have to pull data that isn't being used right away.
A user "owns" various resources on your site, such as comments, etc. If you separate the profile from the user then it's just one more resource. The user is static, while the profile will change from time to time.
Separating it out would also allow you to easily maintain a profile history.
I would keep it separate. Not all your users would want to fill out a profile, so those would be empty fields sitting in your user table. It also means you can change the profile fields without changing any of the logic of your user model.
Depends on the width of the existing user table. Databases typically havea limit to the number of bytes a recird can contain. I fyou are close to (or over which you can usually do if you have lots of fields with null values) the limit, I would add a table with a one-to-one relationship for better performance and less of a likelihood of a record that suddenly can't be inserted as there is too much data for the row size. If you are nowhere near the limit, the add to the exisiting table.