Background
Each Dataverse table contains a primary name column. When displayed in a subgrid, clicking on the primary name column will navigate to the form so that the user can edit that row. Most subgrids in my application work this way.
The Problem
I have a Course form with a list of participants displayed in a subgrid. The subgrid displays each student's name (as a link) and the grade received in the course. There is no appropriate primary name column for this Participant table. To edit the participant record, the user must select the row in the subgrid, then click the subgrid's Edit button. As a result, this UI is different from all other subgrids in the application and I know that user's will click the student name to try to edit the participant record and be confused when they are presented with the student record.
Am I missing something? Is there a better way to handle this?
It's a common problem I face quite often. Here is usually what I would do.
Make sure the Primary Name Column always contains relevant information to the user to be able to quickly identify a record. Sometimes it requires copying information from one or multiple other columns into the primary column.
In your case that would probably means concatenating the student's name and grade.
How to do that?
Common to all solutions below
Use one of the following solution to copy the content of one or several fields into the primary column.
Make sure the solution you select also updates the content of the primary name column when one of the copied field is updated.
Remove or hide the primary column from the form, the name of the record will be displayed at the top of the form anyway and you probably don't want users to play with it.
Display the primary name column in every subgrid.
I would recommend not adding the fields copied into the primary column in the subgrids to avoid confusion.
Solution 1 - Classic Workflow
Create a classic workflow that runs when a record is created / updated
Pros:
Very quick to put in place
Runs synchronously (users will see the name updated in real-time)
Cons:
Not very practical if you need to add business logic (using different fields as source depending on a certain condition for example)
Solution 2 - Power Automate
Create a Flow that runs when a record is created / updated
Pros:
You can implement complex business logic in your Flow
Cons:
Runs asynchronously (users will have to refresh the page after the creation of a record to see the record's name)
According to Power Automate licensing that flow would certainly be considered as an "enterprise flow" and you are supposed to pay 100$ / month. That specific point must be taken with a grain of salt. I had several discussions with Microsoft about it and they haven't given me a clear answer about what would be considered an enterprise flow.
Solution 3 - Plugin
Create a plugin that executes when a record is created / updated
Pros:
You can implement very complex business logic in your Flow
It can run synchronously
Cons:
Pro-code (I put it as a con since Model-Driven App is a low-code / no-code approach but there is nothing wrong about pro-code per say)
Developing a new plugin for each entity where you need this logic is kind of overkill in my opinion. I would consider developing something very generic that would only require some sort of configuration when the logic needs to be applied to a new table.
I am required to make a form which will contain important keywords and their description, with the possibility to search between the words. It is loaded from the Help menu and it is designed to give the users detailed help informations about other components. (Just like every application's Help menu)
I only used forms to query tables, and I was wondering, what is the correct way to achieve this? Does Oracle support any feature that would auto-generate a help-form based on my 'Help' inputs from Property Palettes? or do I have to manually write data into a canvas? if so, how can I search through it?
I considered creating a table and writing help informations in it, but I don't think that is the correct way.
Oracle Forms, unfortunately, does not give you programmatic access to values stored in property palettes, so your solution will need to be custom made.
Create a table, e.g. HELP_TOPICS (keyword, help_text), add a list item that contains all the keywords; when a user selects a keyword, query the table to find the help text, and set the value on a display-only text area item on the page.
I'm currently developing my first MVC component for Joomla 3.x. All in all I'm bit struggling with language/translation issues in database.
My problem is that I need to store translated content of user generated content which comes from the backend. For example someone enters a new item in German (stored in database) and needs a translation in another language. How to accomplish that in Joomla? I don't like to generate a new item for every different language when the rest is all the same.
I thought about a table "item" and a table "item_language" with that structure (strongly simplified for viewing purposes):
item
id PRIMARY INT
price DOUBLE(4,2)
item_language
itemid PRIMARY INT
language PRIMARY CHAR(5)
name VARCHAR(50)
In item_language I would like to store the different translated versions. In the language field there would be the region code (eg. de-DE) to identify the language.
My problems:
How to display the different (translated) versions in backend?
Is this the right database model?
Any help is appreciated!
You have really found yourself a nice task for a first component in Joomla!
A rather generalist answer:
The database model seems right. Alternatively you could encode in JSON the language data, but this could make later query operations potentially difficult. This way you will only have one table to work with.
As far as I know (if you are using JModel / JTable to manipulate the data) can't do this directly, as JTable is really only designed to manipulate single tables.
What you can do:
For editing: figure a way to represent this graphically ( for your users to see and edit this one to many relationship) and to post this data (language texts as an array) to JModel. In the model you can maintain the desired relationships and save the data using JTable.
Viewing (without editing) shouldn't be an issue, it would be a simple JOIN.
If you are willing to create a basic component on github, I might even give you a hand with JModel / JTable.
I found a way to deal with the things I needed.
Thanks Valentin Despa for guiding me in the right direction :-).
Here the whole procedure (simplified - validations and exact steps omitted):
Define the form fields in the models/forms/site.xml as normal.
In views/site/tmpl/edit.php add self coded Javascript (based on jQuery) to deal with the fields which have content in multiple languages stored as JSON in database.
Clone the original form element and modify the needed attributes (id, name, ...) to display a special version just for the defined languages. As content - extract the JSON for the needed language from original field content and display.
Hide the original field with Javascript and append the customized versions to DOM.
Afterwards in tables/site.php I read the dynamically generated content withJInput and build together the original field by generating JSON and saving to database.
It's working like expected.
I would really appreciate if anybody could shed some light on this, as search engine results have been singularly unhelpful so far.
I am attempting to build a GUI for an oracle database through Application Express. There tend to be tricks of how to set up drop down menus through the Graphical User Interface of the product that one uses (for instance I would know how to do this in a product like Microsoft Access).
For instance I have this form
The foreign key for Business (FK_BUSINESS_ID) is just an integer - not terribly user friendly! If it could be a drop down list of business names (BUSINESS.NAME), it would be great. Hiding the business primary key (BUSINESS_ID) would make it look nicer, but isn't altogether relevant.
I have found the source controls for the element in question.
What sort of SQL (or even PL/SQL) could be used to both display this data from the other table, and return the selected foreign key selected by the user when the form is sent?
Solution
Open up the item, and change the type to Select List
For List of Values Definition, enter select BUSINESS.NAME, FK_BUSINESS_ID from [TABLE]
Explanation
Select list shows display values to the user and returns the corresponding ID. Your source can remain the same as before.
I am creating a laboratory database which analyzes a variety of samples from a variety of locations. Some locations want their own reference number (or other attributes) kept with the sample.
How should I represent the columns which only apply to a subset of my samples?
Option 1:
Create a separate table for each unique set of attributes?
SAMPLE_BOILER: sample_id (FK), tank_number, boiler_temp, lot_number
SAMPLE_ACID: sample_id (FK), vial_number
This option seems too tedious, especially as the system grows.
Option 1a: Class table inheritance (link): Tree with common fields in internal node/table
Option 1b: Concrete table inheritance (link): Tree with common fields in leaf node/table
Option 2: Put every attribute which applies to any sample into the SAMPLE table.
Most columns of each entry would most likely be NULL, however all of the fields are stored together.
Option 3: Create _VALUE_ tables for each Oracle data type used.
This option is far more complex. Getting all of the attributes for a sample requires accessing all of the tables below. However, the system can expand dynamically without separate tables for each new sample type.
SAMPLE:
sample_id*
sample_template_id (FK)
SAMPLE_TEMPLATE:
sample_template_id*
version *
status
date_created
name
SAMPLE_ATTR_OF
sample_template_id* (FK)
sample_attribute_id* (FK)
SAMPLE_ATTRIBUTE:
sample_attribute_id*
name
description
SAMPLE_NUMBER:
sample_id* (FK)
sample_attribute_id (FK)
value
SAMPLE_DATE:
sample_id* (FK)
sample_attribute_id (FK)
value
Option 4: (Add your own option)
To help with Googling, your third option looks a little like the Entity-Attribute-Value pattern, which has been discussed on StackOverflow before although often critically.
As others have suggested, if at all possible (eg: once the system is up and running, few new attributes will appear), you should use your relational database in a conventional manner with tables as types and columns as attributes - your option 1. The initial setup pain will be worth it later as your database gets to work the way it was designed to.
Another thing to consider: are you tied to Oracle? If not, there are non-relational databases out there like CouchDB that aren't constrained by up-front schemas in the same way as relational databases are.
Edit: you've asked about handling new attributes under option 1 (now 1a and 1b in the question)...
If option 1 is a suitable solution, there are sufficiently few new attributes that the overhead of altering the database schema to accommodate them is acceptable, so...
you'll be writing database scripts to alter tables and add columns, so the provision of a default value can be handled easily in these scripts.
Of the two 1 options (1a, 1b), my personal preference would be concrete table inheritance (1b):
It's the simplest thing that works;
It requires fewer joins for any given query;
Updates are simpler as you only write to one table (no FK relationship to maintain).
Although either of these first options is a better solution than the others, and there's nothing wrong with the class table inheritance method if that's what you'd prefer.
It all comes down to how often genuinely new attributes will appear.
If the answer is "rarely" then the occasional schema update can cope.
If the answer is "a lot" then the relational DB model (which has fixed schemas baked-in) isn't the best tool for the job, so solutions that incorporate it (entity-attribute-value, XML columns and so on) will always seem a little laboured.
Good luck, and let us know how you solve this problem - it's a common issue that people run into.
Option 1, except that it's not a separate table for each set of attributes: create a separate table for each sample source.
i.e. from your examples: samples from a boiler will have tank number, boiler temp, lot number; acid samples have vial number.
You say this is tedious; but I suggest that the more work you put into gathering and encoding the meaning of the data now will pay off huge dividends later - you'll save in the long term because your reports will be easier to write, understand and maintain. Those guys from the boiler room will ask "we need to know the total of X for tank grouped by this set of boiler temperature ranges" and you'll say "no prob, give me half an hour" because you've done the hard yards already.
Option 2 would be my fall-back option if Option 1 turns out to be overkill. You'll still want to analyse what fields are needed, what their datatypes and constraints are.
Option 4 is to use a combination of options 1 and 2. You may find some attributes are shared among a lot of sample types, and it might make sense for these attributes to live in the main sample table; whereas other attributes will be very specific to certain sample types.
You should really go with Option 1. Although it is more tedious to create, Option 2 and 3 will bite you back when trying to query you data. The queries will become more complex.
In fact, the most important part of storing the data, is querying it. You haven't mentioned how you are planning to use the data, and this is a big factor in the database design.
As far as I can see, the first option will be most easy to query. If you plan on using reporting tools or an ORM, they will prefer it as well, so you are keeping your options open.
In fact, if you find building the tables tedious, try using an ORM from the start. Good ORMs will help you with creating the tables from the get-go.
I would base your decision on the how you usually see the data. For instance, if you get 5-6 new attributes per day, you're never going to be able to keep up adding new columns. In this case you should create columns for 'standard' attributes and add a key/value layout similar to your 'Option 3'.
If you don't expect to see this, I'd go with Option 1 for now, and modify your design to 'Option 3' only if you get to the point that it is turning into too much work. It could end up that you have 25 attributes added in the first few weeks and then nothing for several months. In which case you'll be glad you didn't do the extra work.
As for Option 2, I generally advise against this as Null in a relational database means the value is 'Unknown', not that it 'doesn't apply' to a specific record. Though I have disagreed on this in the past with people I generally respect, so I wouldn't start any wars over it.
Whatever you do option 3 is horrible, every query will have join the data to create a SAMPLE.
It sounds like you have some generic SAMPLE fields which need to be join with more specific data for the type of sample. Have you considered some user_defined fields.
Example:
SAMPLE_BASE: sample_id(PK), version, status, date_create, name, userdata1, userdata2, userdata3
SAMPLE_BOILER: sample_id (FK), tank_number, boiler_temp, lot_number
This might be a dumb question but what do you need to do with the attribute values? If you only need to display the data then just store them in one field, perhaps in XML or some serialised format.
You could always use a template table to define a sample 'type' and the available fields you display for the purposes of a data entry form.
If you need to filter on them, the only efficient model is option 2. As everyone else is saying the entity-attribute-value style of option 3 is somewhat mental and no real fun to work with. I've tried it myself in the past and once implemented I wished I hadn't bothered.
Try to design your database around how your users need to interact with it (and thus how you need to query it), rather than just modelling the data.
If the set of sample attributes was relatively static then the pragmatic solution that would make your life easier in the long run would be option #2 - these are all attributes of a SAMPLE so they should all be in the same table.
Ok - you could put together a nice object hierarchy of base attributes with various extensions but it would be more trouble than it's worth. Keep it simple. You could always put together a few views of subsets of sample attributes.
I would only go for a variant of your option #3 if the list of sample attributes was very dynamic and you needed your users to be able to create their own fields.
In terms of implementing dynamic user-defined fields then you might first like to read through Tom Kyte's comments to this question. Now, Tom can be pretty insistent in his views but I take from his comments that you have to be very sure that you really need the flexibility for your users to add fields on the fly before you go about doing it. If you really need to do it, then don't create a table for each data type - that's going too far - just store everything in a varchar2 in a standard way and flag each attribute with an appropriate data type.
create table sample (
sample_id integer,
name varchar2(120 char),
constraint pk_sample primary key (sample_id)
);
create table attribute (
attribute_id integer,
name varchar2(120 char) not null,
data_type varchar2(30 char) not null,
constraint pk_attribute primary key (attribute_id)
);
create table sample_attribute (
sample_id integer,
attribute_id integer,
value varchar2(4000 char),
constraint pk_sample_attribute primary key (sample_id, attribute_id)
);
Now... that just looks evil doesn't it? Do you really want to go there?
I work on both a commercial and a home-made system where users have the ability to create their own fields/controls dynamically. This is a simplified version of how it works.
Tables:
Pages
Controls
Values
A page is just a container for one or more controls. It can be given a name.
Controls are linked to pages and represents user input controls.
A control contains what datatype it is (int, string etc) and how it should be represented to the user (textbox, dropdown, checkboxes etc).
Values are the actual data that the users have typed into the controls, a value contains one column for every datatype that it can represent (int, string, etc) and depending on the control type, the relevant column is set with the user input.
There is an additional column in Values which specifies which group the value belong to.
Each time a user fills in a form of controls and clicks save, the values typed into the controls are saved into the same group so that we know that they belong together (incremental counter).
CodeSpeaker,
I like you answer, it's pointing me in the right direction for a similar problem.
But how would you handle drop-downlist values?
I am thinking of a Lookup table of values so that many lookups link to one UserDefinedField.
But I also have another problem to add to the mix. Each field must have multiple linked languages so each value must link to the equivilant value for multiple languages.
Maybe I'm thinking too hard about this as I've got about 6 tables so far.