I have a "Note" entity for my application, where its attributes are "Title", "Body", and "Tags".
I'm having trouble with the "Tags" attribute; I want to be able to input multiple tags when creating the Note, and then the program will be able to give me other Notes that have the same tag (Exactly like how Stackoverflow uses tags for questions). I'm not quite sure what the relationship between the entities should be.
How should I approach this problem?
Create Tag entity and add to-many relationship from Note to Tag and also to-many relationship from Tag to Note (and set set them to be inverses of each other).
Tag shouldn't be an attribute, but a many-to-many relationship. A Note can have multiple Tags (I assume) and a Tag can be added to multiple different Notes.
This way you'll be able to set up a fetch request to return all the Notes that have a specific Tag.
Related
Having a doubt on REST API URI design.
Let's consider each Post has one or more tags. So, a tag could be retrieved by
GET /posts/1/tags/1
Tags are stored uniquely in DB with an ID. So I could access full detail of a tag using
GET /tags/1
If Post information needed, then I could use query parameter
GET /tags/1?post=1
My question is why the first format widely suggested over second/third format.
Suggest me use case/scenario to prefer first format or complications with second/third format.
why the first format widely suggested over second/third format.
This is not the case. The three are used for different things.
You must first ask if a tag can exist without a post. I'd say yes. Because of this, the second form
GET /tags/1
is a good URI to get the representation of a tag.
Next, ask yourself if a post can have multiple tags. I'd again say yes. Because of this the first form is a good way to get a specific tag of a post. More general, the form
GET /posts/1/tags
returns all tags that are used for post 1. This is a collection resource. One of those tags is tag 1 which can be navigated to by
GET /posts/1/tags/1
Note that the first and the second form both identify tag 1. Both forms can be used at the same time.
The third form makes no sense at all. Query parameters after the ? like post=1 are generally used to filter a collection resource. One could say: "Give me all tags that are used on posts 1, 23, and 42. This could be formulated as
GET /tags?post=1,23,42
Here we filter the collection resource of all tags by a condition.
Your third form uses a query parameter post=1 on a single resource. But it makes no sense to filter a single tag.
A fourth form could be useful: Give me all posts that use a tag:
GET /tags/1/posts
This would return the collection resource of all posts that use tag 1.
And even a fith form with the same meaning as fourth would be possible:
GET /posts?tag=1
Summary:
When thinking about REST URIs, think about resources. What are your resource? What are the relations between them? Can one type of resource exist only "inside" another type of resource (a hotel room can only exist inside a hotel) or can it exist on its own (a tag can exist even if not post is tagged with it). What could be a subresource of another resource? What collection resources exist? How can they be filtered?
I have a rails app that includes tagging for blog posts using the gem acts-as-taggable-on. My idea is to extend the tagging mechanism of this gem using a moderate-link approach where I can choose to create a few users as tag owners and they can choose to link one tag to another as parent/child.
Presently the system has independent tags like Education, Child Education and Distance Education
The tag owner of Education can choose to select Child Education and Distance Education
as first level child and link them together. This relationship wont be visible until its approved by the Taxonomist(A tag administrator).
Similarly, an end user can also suggest Distance Education tag to be the child of Education and this request will become visible to the tag administrator. Based on his approval the relationship will be established.
These are the few questions I have pertaining to the requirement above:-
Is it recommended to extended the gem or should I use an independent tagging model written from scratch to support this hierarchical system ?
If I go ahead with the schema provided by the gem , what kind of a model should be used to design such a requirement. Specifically, should I use a single table with a parent_id column with the tag id and tag name ? Or should I maintain their relationship in a separate table with many-to-many associations (tag_id, parent_tag_id (as Foreign key)).
I am also new to data structures so I will need some initial inputs on the choice of algorithms to efficiently traverse between a tag family. Using linked list was one my options however considering Rails mantra of convention over configuration , I am really unsure of how to proceed on this.
I remember doing something similir like 4 years ago with ActsAsTree.
There s also an example of how to do it manually here.
Both options will need that parent_id column on your tags table and are really straightforward. Just create a tag.rb in your models folder and extend Tag class.
Ps. Its been a long time, but i remember having to check that there are no loops, just keep it in mind
(Using Ektron version 8.6.1)
Say I have a smartform ContactInfo, something like:
<ContactInfo>
<Name></Name>
<Email></Email>
</ContactInfo>
I would like to create another smartform (e.g. NewsArticle) and "embed" ContactInfo inside
<NewsArticle>
<Title></Title>
<Summary></Summary>
...
<ContactInfo>
<Name></Name>
<Email></Email>
</ContactInfo>
</NewsArticle>
My solution thus far has been to include a Resource Selector field to add a reference to an existing smartform instance. I would prefer to make the association at the configuration level, to make the data entry workflow more intuitive.
I'm using Bill Cava's ContentTypes and generating classes from smartform XSDs, so it would also make the presentation code more natural and type-safe in that embedded fields could be accessed directly (rather than having to make another request based on a reference ID, which may or may not be an ID to the smartform I'm expecting).
I gather this is not possible out of the box; I'm not opposed to hacking Workarea code to make something like this work. Does anyone have experience with a scenario like this?
I heard from an Ektron rep that they are planning on elevating the role of smartforms in an upcoming summer release - can anyone offer some more info to that point? Perhaps smartform composition like I've described will be supported?
Currently it isn't possible to do smartform composition. Depending on why/if you actually need a second smartform definition, you could just define the contact info in the news article.
If the contact info smartforms are related to the news articles in a one to many or many to many fashion, then using the resource selector as you have is the only way that I know of to create the relationship you are looking for.
If the relationship is one-to-one or many-to-one, then I'd suggest doing away with the separate smartform definition.
If you can clarify the workflow you are trying to achieve for the content authors, I might be able to respond better.
The Content Types would represent the data in the CMS. Suppose, as in your example, a NewsArticle contains a reference to a ContactInfo. Embedding the ContactInfo inside your NewsArticle might make sense from a presentation perspective, but it turns your ContentTypes into a one-way data model. You would lose the ability to construct a new NewsArticle and persist it into the CMS.
What might work well for you is to leave the content types as-is, with the id of the ContactInfo from the resource selector. Then create a NewsArticleDisplayModel... essentially a view model that contains the news article data plus ContactName and ContactEmail.
Now, if you need the contact info to be searchable, you could get really fancy with CMS Extensions and hook into the OnBeforePublish event to update searchable metadata with the name from the ContactInfo, so that the NewsArticle can be searched for using the values from the other "embedded" resource. That could get kinda tricky, though... ideally you'd have to also hook into the publish events of the ContactInfo objects in case something changes on that side, too. Then do you create a custom database table to track which NewsArticle content ids are using a particular ContactInfo?
Your solution can get as complex as it needs to, but I would keep the content blocks separate. If nothing else, you'll end up with a more maintainable and upgradable solution.
We are building a webapplication which uses a database. Also we use an object relational mapper to access the database. One aspect of authorization in the webapplication is that the user may access an object referred to by an URL. The URL contains a unique id (for example the Primary Key) to a specific record in the database. Consider the following example.
a user may belong to many groups and a group may have many users (many-to-many).
a survey belongs to a group (many-to-one).
a survey may have multiple questions. (many-to-one).
Say we have the following URL: http://app.local/question/edit/10. This means we want to edit question with PK 10. Now, we want to verify if the logged in user may access question with PK 10. This can be done by retrieving this question, then it's survey then it's group and then all its users. If any of the users is the same as the logged in user the logged in user may access the question.
To generalize this a bit; we want to check if a record is reachable from another record by the known many-to-one or many-to-many relations. So if there is a many-to-one relation (like with a survey and a question then we should check if a user is reachable from the question through the survey and then through the group. The group has a many-to-many relation with the user so we should check if any (not all) of the users is the same as the logged in user.
If a table has multiple many-to-one relations, say; we can attach a CSS template to a survey and this template also belongs to a group then we have to check if a user is reachable from all many-to-one relations (thus the group and the template). The same holds of course for multiple many-to-many relations.
Are there Object Relation Mappers which support this behaviour? And what is this behaviour called, maybe reachability? Does Propel (for PHP) support this behaviour? I think this reachability can be done in any of the following two ways:
Execute a query to get each "parent", uses many queries)
Join all necessary tables to see if a record exists (the reachable users matches the logged in user) in one query.
Furthermore this behaviour of the ORM should support nested sets, thus if a group contains nested set behaviour it should also try to reach a user through the group's parent.
I don't think this kind of behaviour should be restricted to authorization; objects should simply be able to see if they can reach another object.
Note that I do not mean persistence by reachability: http://jpaobjects.sourceforge.net/m2-site/main/documentation/docbkx/html/user-guide/ch08s03.html.
Or... am I simply looking at this authorization wrong and is there a far better and different approach with an ORM?
I've handled this in the past using nested resources in Ruby on Rails (which uses the Active Record ORM). Rather than http://app.local/question/10/edit, the URI would be http://app.local/survey/5/questions/10/edit
In the controller you load both the question and survey. You check authorization by comparing the survey to the authenticated user's group memberships. One way to engineer this would be to embed this logic into the User class. For example, in the controller you have question and survey (and the relationship between the two is well understood by the ORM, i.e. question.survey). You could then check access as user.hasAccess?(question), which would be a relatively easy method to write. Pseudocode:
class User < ActiveRecord::Base
def hasAccess?(question)
return question.group.users.include?(self)
Yes, this will result in several queries behind the scenes, but ORMs do the work. I do it this way because you're left with solid schema and easy to read code. Don't optimize until you actually have a performance problem.
I am creating a web site for a customer and they want to be able to create articles. My idea is to tag them so I am going to implement the system.
What is the best design, both from an architectural and a perfomance perspective:
1. To have table with all tags and then have a one to many relationship table that links a tag like this:
articles table with ID
tags table with ID
one to many table with columns Article.ID and Tags.ID
2. To have one table with articles and one with tags for articles like this:
articles table with ID
tags table with Article.ID and tag text
Thanks in advance!
Your first option is the most appropriate and theoretically right.
Guess, your clients do not think tags like a nice feature to have because everybody has it - they would like to have search by tags. Even if they don't yet understand their needs and really want to have tags because everybody around has them - they will realize their needs soon.
First option will give you better search operation performance.
Implement separate table for articles, tags and many-to-many between them.
Definitely the first option.
Apart from the other benefits, you could enforce some regularity in using tags, by checking if the tag (or a similar one) is already present before adding it, allowing users to select from existing tags, and/or allowing only superusers to add new tags.
This way you avoid mispellings or alternate spellings of the same tags (i.e. US, USA, USofA, U.S.A., U.S, US., America, Amerika, Amrica and so on when labelling something about the United States)