pls help me understand how i can add Entity in table.
(Use Tutorial) I create Spring boot app - login/registration/home - with Security, SpringJpa, Hibernate and Thymeleaf. Tutorial it is always cool, but can i do something without that?
I decide to expend my app, and understand that i am real beginner.
So, my problem, i have home.html page, with Courses (three courses), that i want to add in my new page cabinet.html one of this course. New page have empty bootstrap table, but i want add course and see this entity in table!
link to view html page https://drive.google.com/drive/folders/1dnn-IKkpaBeouyqnGU13YLf1GBPVd_jQ?usp=sharing
My Question, after registration and login, what i need to write in backend, that on of my course appear after (click button add) in List Table in the Cabinet?
I think this is may be :
Course Entity (id, string name, string date) that saves to MySQL. Courses Repository. Courses service with method find-All or save? ServiceImpl, Controller, PostMapping with RequestParam?
And what thameleaf tegs i need to add in my table that field courses entity views in table? Pls help
Related
I've been researching this for a while and still couldn't find a satisfactory answer for my problem.
I have an entity on my postgres DB (product) that has a ManyToOne relationship with another entity (Dun).
Each product may have N duns.
On my PUT endpoint, the desired behavior would be:
Every time I update a product, it replaces all the duns with the ones provided on the endpoint.
Is there any way to handle it automatically by Hibernate/JPA?
In order to make it easier to test and explain the issue, I've uploaded a project on Github on the following link https://github.com/brunapereira/jpaexample
If there's no way to handle it automatically by JPA, what's the best way to solve it with code?
Thanks in advance,
First, you need to remove Duns by product id, then get the product by id, add the new duns then save back.
I want to save data of a form into two tables simultaneously. The form contains multiple identical rows with some fields like
item, unit, unit_price, total.
1.) In the table1 I would like to save some data like id(auto generated, primary key), date, creator.
2.) In table2 I would like to save the id(auto generated, primary key), fid(id of the table1, foreign key), item, unit, unit price, total. Remember, in table2 multiple rows will be save from the form data.
I can't figure it out. Please help me with a valid step by step example, and please don't use static or pre-defined data, take the data from form only.
Is your form an HTML form on a web page, and are you writing a Spring MVC application? Have you setup Spring Security, or some other authentication mechanism such that you know who the user is? If so, here is one approach:
Define a plain old Java object (POJO) with fields id, unit, unit-price, total, creator, currentDate; perhaps you would name it Item.
Define another plain old Java object perhaps named "ItemHistory", with its own ID and a reference to an Item.
In the first POJO ("Item") include a reference to a list of ItemHistorys.
Annotate both classes with Hibernate/JPA annotations, such that the Item has a OneToMany relationship to ItemHistory.
Define a Spring MVC controller with a method annotated as a POST method, with an Item as one parameter, and an Authentication as another parameter (supposing you have configured Spring Security, the Authentication will automatically be populated with the identity of the currently-logged-in user. In this method, set the currentDate and author of the Item to the current date and the principal from the Authentication parameter. If it is a new Item (no id yet), add the first ItemHistory as a copy of the Item itself. If it is an existing item, add another ItemHistory if needed.
Define a Spring bean, perhaps named ItemService, with a method annotated as transactional, that takes an Item and saves it. Call this bean from the REST controller. Such a Spring bean is known as a DAO (data access object).
There are other strategies, but if you already have Spring MVC, Spring Security, and Hibernate/JPA configured to your needs, this one is pretty straight-forward.
I have two tables that have relationship like
tbl_department whose entities are dept_id and dept_name where dept_id is primary key and next table is tbl_employee whose entities are emp_id, emp_name and dept_id where dept_id is foreign key that references the dept_id of tbl_department. Now, in my jsp page i want to display the format like this:
Emp_id|Emp_name|dept_name.
I am doing above display in JSP page using the JSTL sql tag, and I know it violates the MVC architecture, so, how could I solve this problem i.e. how can I do this relationship mapping it in either Model or Controller in Spring instead in JSP page. Is there any examples or tutorial I can find for this kind of problem
Thank you
First, you have to decide whether it would be worth your while using Hibernate. You should research this yourself to decide whether the rest of your app would benefit from using it (too big a topic to address here).
Assuming you only want to do the use case you have outlined in the question, I'd suggest you use Spring's JDBC support and create a Service (or just a DAO) to perform the SQL that you are currently using in your JSP. I'd create a simple DTO class to hold the Emp_id|Emp_name|dept_name data and populate that in your Service/DAO and then pass it to the JSP via the Controller.
This Spring MVC Example (skeleton) app would be a good place to start, to see how those components are created and wired together.
Am new to ASP.NET MVC 3.0. Request expert's view on the below mentioned scenario.
I have a customer details page, where only Name is editable. There are 10 other customer properties that are non editable and displayed using SPAN. When user submits the page, I need to update only the Name.
If am using EF, I will have to load customer again, overwrite name and then save. Otherwise I will have to maintain customer model somewhere.
Anyone tried caching model (or viewmodel) using session id? Is it a good practice?
You are almost thinking in right direction.
If am using EF, I will have to load customer again, overwrite name and then save. Otherwise I will have to maintain customer model somewhere.
In Update Method **Load Customer again and update name Only as required and then save
**For 2 reasons
The first and most important rule is 'don't trust user data'. and
Concurrency and to avoid saving old data. See this example
Instead of using Session, I will suggest to use Hidden Field for record LastUpdateDateTime and Customer ID which will be posted back in the model to retrieve record and verify LastUpdatedtime with database record
Tipically, you should use a view model different than the database model. Having said that,in your current case the situation is very simple, submit only the name to the controller and then set the Name property of the object you get from EF with the submitted name.
Caching the view model or the model isn't your concern. The database model caching is handled by EF, your problem is mainly a lack of clear application layering. IN fact I strongly suggest to learn a bit more about the MVC pattern, basic application architecture (2-3 layering) and when and how to use a OR\M (which EF is).
use hidden inputs for other properties in your form. In that way you can get all properties binded to your EF entity and you dont need to get entity again from db.
#Html.DisplayFor(model=>model.x)
#Html.HiddenFor(model=>model.x)
or you can serialize the entity(if you use POCO entities) and set to hidden input. When you post back you should deserialize the entity.
My choice is always first one. :)
I have having a little trouble wrapping my head around the design pattern for MVC when the data type of the model property is very different than what I wish to display in a form. I am unsure of where the logic should go.
Realizing that I am not really sure how to ask the question I think I will explain it as a concrete example.
I have a table of Invoices with a second table containing the InvoiceDetails. Each of the InvoiceDetail items has an owner who is responsible for approving the charge. A given invoice has one or more people that will eventually sign off on all the detail rows so the invoice can be approved. The website is being built to provide the approval functionality.
In the database I am storing the employee id of the person who approved the line item. This schema provides me a model with a String property for the Approved column.
However, on the website I wish to provide a CheckBox for the employee to click to indicate they approve the line item.
I guess my question is this -- how do I handle this? The Model being passed to the View has a String property but the form value being passed back to the Controller will be of the CheckBox type. I see two possible ways...
1) Create a new Model object to represent the form fields...say something like FormInvoiceDetails...and have the business logic query the database and then convert the results to the other type. Then after being submitted, the form values need to be converted back so the original Model objects can be updated.
2) Pass the original InvoiceDetails collection to the View and have code there create render the CheckBox based on the value of the String property. I am still not sure how to handle the submission since I still need to map back the form values to the underlying database object.
Maybe there is a third way if not one of these two approaches?
To make the situation a bit more complicated (or maybe it doesn't), I am rendering the form to allow for the editing of multiple rows (i.e. collection).
Thanks for any insight anybody can provide.
You need a ViewModel, like #Justn Niessner suggests.
Your controller loads the complete model from the database, copies just the fields it needs into a ViewModel, and then hands the ViewModel off to the view for rendering.
I'd use Automapper to do the conversion from Model to ViewModel. It automates all the tedious thingA.x = thingY.x; code.
Here is an additional blog post going over in detail the use of ViewModels in the Nerd Dinner sample.
I believe what you are looking for is the ViewModel.
In cases where you are using a ViewModel, you design the ViewModel to match the exact data you need to show on your page.
You then use your Controller to populate and map your data from your Model in to your ViewModel and back again.
The Nerd Dinner ASP.NET MVC Example has some very good examples of using ViewModels.