i was asked to do a book manager at university with hibernate and mysql. I have a simple question. If i choose to do a web application, grails already uses hibernate. GORM runns over hibernate. so to use mysql i only need to configure jdbc grails drivers and that's it?
i mean, "for the project you must use hibernate and mysql" - this are the requirements. So can i do that way?
thanks in advance,
JM
Yes, of course you can.
You'll need to get the MySQL JDBC driver from this location.
Grails? When you're new to programming? Whose idea was this?
Personally, I think that taking on all these unknowns is risky for someone who's "new to programming." Do you know anything about SQL or JDBC? Have you ever written a web project before? This could be difficult.
I don't know how to be more specific. Download the JDBC JAR from the link I gave you.
I'd recommend that you start with a JDBC tutorial first. Hibernate is not for you - yet.
Hibernate is an object-relational mapping tool (ORM). It's a technology that lets you associate information in relational database tables to objects in your middle tier. So if you have a PERSON table with columns id, first, and last Hibernate will let you associate those data with the private data members in your Person Java class.
That sounds easy, but it gets complicated quickly. Your relational and object models might have one-to-many and many-to-many relationships; Hibernate can help with those. Lazy loading, caching, etc. can be managed by Hibernate.
But it comes at a cost. And it can be difficult if you aren't familiar with it.
If you have a deadline, I'd recommend creating a Java POJO interface for your persistence classes and doing the first implementation using JDBC. If you want to swap it out for Hibernate later on you can do it without affecting clients, but you'll have a chance of making progress without Hibernate that way.
Related
Recently, I started investigation of activiti framework to integrate it into my current project.
In our project we use teradata database.
So I added activiti dependency and created simple bpmn process for testing purposes.
I tested this process with h2 inmemory database and it worked fine.
But when configured project to use teradata I've got exception on spring boot application startup.
Caused by: org.activiti.engine.ActivitiException: couldn't deduct database type from database product name 'Teradata'
I have googled and found only this topic on internet space:
https://hub.alfresco.com/t5/alfresco-process-services/does-activiti-support-teradata-database/m-p/17587#M287
It seems there is no way to integrate activiti and teradata for now.
So the reason why I am here posting this question is that I just want to make sure there is no way to reach integration between those technologies.
Any suggestions and ideas will be welcomed. Thank you.
Activiti is an open source product and can be "adapted" to almost any back end transactional database. Transaction support is a must as any BPMN engine is basically a state machine.
Database access is isolated in the entity layer and specific SQL is managed by the Ibatis ORM.
To integrate a specific database, you will need to modify the entity and ORM layers.
Certainly possible and actually not that much work (typically about 30 hours in my experience), but it is work you have to do and maintain yourself.
I am designing a database using MySQL Workbench. I've defined a bunch of tables and set up relationship via foreign keys. I am preparing to forward engineer this model to a database schema. Where do I go from there?
What I am looking to do is take the new database and create the Java entities that will correspond to said tables for use in a SpringBoot application. I have seen a few posts that talk about different methods including Eclipse-based solutions that generate these artefacts, but many of these are older solutions and I'm not sure what the current "hot" tool is. Using Spring Source Tool Suite, I installed JBoss Tools which claims to do this via their Hibernate Tools Reverse Engineering utility, but I can't find any step-by-step documentation on how to proceed.
Since the project is in its infancy, I expect frequent changes to be made to the model and would like to consider a solution that can handle those types of updates as well.
In addition to the utilities listed in the comments, there are a couple of other possibilities I want to mention:
Maven Archetypes - Maven-based templating toolkits that can generate projects according to different configurations
JHipster - Yeoman-based templating toolkit that can generate opinionated best-practice Spring-Boot monolithic or microservice applications.
Number 2 is currently my go-to solution as it has a very active community and does a lot of "cool stuff".
The problem I have with the various ORM modules available for databases like MySQL and MongoDB is the inability to keep model information coupled with the database itself.
I want to be able to add a model to my ORM setup at runtime via an administrative HTTP interface and give it some fields that may be ascribed to various predefined data types (like 'email' or 'telephone number'). Possibly the most contentious feature I'm after is the ability to cast a field as a data type that has already been previously defined by the user as a model.
Is this just me trying to have my cake and eat it? Can anybody see a way of implementing something like this? All the ORM modules I've seen so far simply require instantiating models at application level, essentially before runtime.
It's probably worth mentioning I'm hoping to implement this in a Node environment (not a classic LAMP setup).
EDIT:
I take it from the lack of community bite that I may have stumbled back into the Object-Relational Impedance Mismatch issue here?
If your solution depends on multiple drivers, you can try light-orm. It is simple wrapper for relations dbs.
I'm trying to familiarize myself a bit more with database programming, and I'm looking at different ways of creating a data access layer for applications. I've tried out a few ways but there is such a jungle of different database technologies that I don't know what to learn. For instance I've tried using datasets with tableadapters. Using that I am able to switch data provider rather easily (by programming against the interfaces such as IDbConnection). This is one thing I would want to achieve. But I also know everyone's talking about LINQ, and I'm trying to get to know that a bit better too. So I have tried using Linq to Sql classes as the data access layer as well, but apparently this is not provider independent (works only for SQL Server).
So then I read about the Entity Framework (which just as Linq to SQL apparently has gotten its share of bashing already...). It's supposed to be provider independent everybody says, but how? I tried out a tutorial to create an entity data model, but the only providers to choose from were SQL Server/Express. Just for learning purposes, I would like to know how to use the entity framework with MS Access/OleDb.
Also, I would appreciate some input on what is the preferred database technology for data access. Is it LINQ still after all the bashing, or should you just use datasets because they are provider independent? Any pointers for what to learn would be great, because it's just too much to learn it all if I'm not going to use it in the end...!
the only providers to choose from were SQL Server/Express
The .NET Framework only includes EF providers for SQL Server and SQL Server Compact. If you need to access another DBMS, you need to install a third-party provider. For instance, there's a free provider for SQLite, with designer support. There are also a few (commercial) providers made by Devart, for various DBMS. As far as I know, there are no EF providers for OleDB or ODBC...
I really like the metaphor from Scott Hanselman: "I'm not a plumber, but I do know what an S-Bend is."
Personally, I think you should have a working knowledge of all the variety of ways to access data.
ADO.Net, EF, Linq2Sql, txt files, xml etc etc etc.
Have a look at the Nerd Dinner and the Music Store samples. See the way they access data (how do they do Unit Tests, Mocking framework, IOC etc)
Regarding data providers, personally I would avoid Access. It is just as easy to get a Sql Express or Mysql installation running and looks better on your resume.
(For what its worth, this question discusses setting up mysql for EF.)
I'm going to start a new project which is going to be small initially but may grow to big over the years. I'm strongly convinced that I'm going to use ASP.NET MVC with jQuery for UI. I want to go for MySQL as database for some reasons but worried on few things.
I'm totally new to Linq but it seems that it is easier to use once you are familiar with it.
First thing is that accessing data should be easy. So I thought I should use MySQL to Linq but somewhere I read that it is not directly supported but MySQL .NET connector adds support for EntityFramework. I don't know what are the pros and cons of it. DbLinq is what I also heard. I would love if I can implement repository pattern as it allows to apply filter in logic layer rather than in data access layer. Will it be possible if I use Entity Framework?
I'm also concerned about the performance. Someone told me that if we use Entity framework it fetches lot of data and then filter it. Is that right?
So questions basically are -
Is MySQL to Linq possible? If yes where can I get more details on it?
Pros and cons of using EntityFramework or DbLinq with MySQL?
Will it be easy to access data using EntityFramework or DbLinq with MySQL?
Will I be able to implement repository pattern which allows applying filter in logic layer rather than data access layer (when I use EntityFramework with MySQL)
Does it fetches hell lot of data from database and then apply filter on it?
If it sounds too many questions from my side in that case, if you can just let me know what you will do (with a considerable reason) in this situation as an experienced person in this area, that should answer my question.
As I am fan of ALT.NET I would recomend you to use NHibernate for your project instead of EntityFramework, you may google for the advantages over it, I am convinced you'll choose it.
Based on the points you've mentioned, then I would seriously consider going with MS SQL instead of MySQL initially and implementing LINQ-to-SQL instead of Entity Framework, and here's why:
The fact that you are anticipating a lot of traffic initially tells me that you need to think about where you plan to end up, rather than where to start. I have considerably more experience with MS SQL than I do with MySQL, but if you're talking about starting with the community version of MySQL and upgrading later, you're going to be incurring a significant expense anyway with the Enterprise version.
I have heard there is a version of LINQ that supports MySQL, but, unless things have changed recently, it is still in beta. I am completing an 18-month web-based project that used ASP.NET MVC 1.0, LINQ-to-SQL, JavaScript, jQuery, AJAX, and MS SQL. I implemented the repository pattern, view models, interfaces, unit tests and integration tests using WatiN. The combination of technologies worked very well for me, and I plan to go with the same combination for a personal project I'm developing.
When you get MS SQL with a hosting plan, you typically have the ability to create multiple databases from that single instance. It looks like they give you more storage because they give you multiple MySQL databases, but that's only because the architecture only supports the creation of one database per instance.
I won't use the Entity Framework for my ASP.NET MVC projects, because I wasn't crazy about ADO.NET in the first place. I don't want to have to open a connection, create a command object, populate a parameter collection, issue the execute method, and then iterate through a one-way reader object to get my data. Once you see how LINQ-to-SQL simplifies the process, you won't want to go back either. In the project I mentioned earlier, I have over 60 tables in the database with about 200 foreign key relationships. Because I used LINQ-to-SQL with the repository pattern in my data layer, I was able to build the application using not a single stored procedure. LINQ-to-SQL automatically protects against SQL injection attacks and support optimistic and pessimistic concurrency checking.
I don't know what your project is, but you don't want to get into a situation where you're going to have trouble scaling the application later. Code for the end result, not for the starting point, and you'll save yourself a lot of headaches later.