Object-relational mapping (ORM) is a technique for mapping between object-oriented systems and relational databases.

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How to convince teammates to start separating database queries into one single layer

We are using ORM with bunch of database models and those ORM database queries (and models, of course) - are literally all over application from top to bottom. And when change in model structure ...
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What are the non-technical reasons that make Object-Relational Mapping tools (ORMs) so difficult to write?

I know the technical pitfalls of writing an ORM are pretty well-known nowadays, but what are some non-technical factors (e.g., Scope) that make it difficult to writing a good ORM? I have already ...
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115 views

Ruby best practices for Data Access layers

I'm starting my way into Ruby development and have some questions that I hope you can give your best opinion to better design some command line applications I'm developing. What are the best patterns ...
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4answers
2k views

Programmatically extending Hibernate table/entity definitions in Spring, how?

I would like to know if there is a way —maybe with AOP— to extend table/entity definitions so that I can add functionality across the board that requires persistence. Let me explain what I want to do ...
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Is inline SQL still classed as bad practice now that we have Micro ORMs?

This is a bit of an open ended question but I wanted some opinions, as I grew up in a world where inline SQL scripts were the norm, then we were all made very aware of SQL injection based issues, and ...
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1answer
56 views

Using “Id” as Primary Key in green field Dapper Contrib MVC 5 site

I am creating a new site and will base it on ASP.NET MVC 5 & Dapper Contrib. I want to go all in with all these technologies - and get all the time saving / convention over configuration / terse ...
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1answer
60 views

Why does ORM persist() functionality use references to populate insert_id and not return?

My understanding of how ORM persist works: //ORM "persist" oversimplification function persist(&$entity) { ... $insertId = api_actual_db_insert(...); $entity->setId($insertId); } /...
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3answers
250 views

Domain/Model objects attributes good practices

Simple question: Should model/domain objects only include attributes that are meant to be persisted in a database or serialized to any other specific format? My understanding of a domain/model object ...
2
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1answer
86 views

Can I manage transactions in the UI

Do I need an "application/service" layer to manage transactions if the domain layer only services the UI? In other words, can't I just manage transactions in the UI when I have only one consumer of ...
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4answers
251 views

Encapsulation for complex queries

I tried asking this question first on StakOverflow in a more concrete manner, but after being pointed here I realized I should rephrase it in more general terms; however, you can still review the ...
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2answers
303 views

How to handle complex calculated fields in an ORM

In our API we've got a few central datatypes which need to be "decorated" (so to speak) after retrieval from the database with calculated values. The database is accessed through an ORM which follows ...
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3answers
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Do we achieve 100% Persistence Ignorance solution if we're not using ORM's POCO objects to model the Domain?

Persistence ignorance is ability to retrieve/persist standard objects, where standard objects are considered as classes focused on particular business problem and thus don't contain any ...
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How do ORMs order commands to prevent constraint violations?

Purely out of curiosity, I was hoping someone could explain how ORMs (like Hibernate or Entity Framework) determine the order that they need to execute SQL UPDATEs, INSERTs and DELETEs. Is there an ...
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0answers
25 views

Approach for querying an arbitrary set of user submitted fields and values in Spring application? Like a shopping site sidebar search?

I am working on a Spring Boot and Angular application which has a requirement to search based on any number of the available filters being applied to a list. For example, a user searches on 'Title' ...
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4answers
14k views

Entity Framework with large systems - how to divide models?

I'm working with a SQL Server database with 1000+ tables, another few hundred views, and several thousand stored procedures. We are looking to start using Entity Framework for our newer projects, and ...
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2answers
98 views

Is it a bad idea to put externally dependent logic in ORM classes?

Case in point in Entity Framework, but this is a design question which has applicability to any ORM. In the current application we have a couple of ORM data classes which do stuff not directly ...
4
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1answer
438 views

Unit testing Eloquent outside of Laravel

How can I unit test my Eloquent models when I'm using the ORM outside of Laravel? What I'm hoping to do it run tests on each model but somehow mock the database connection/query/builder(?) object. ...
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2answers
132 views

Using ORMs in two separate programs which share a DB

I have an application that is divided into two main parts: A web crawler written in Python A REST API written in Golang They share a MySQL database, which is mainly populated/updated by the web ...
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5answers
448 views

To which layer does this code belong?

When I say "Revisional Data Model", I mean a data model where information is never lost: Deletes never destroy any rows, and updates always cause an insert somewhere else to preserve a row's previous ...
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0answers
49 views

Managing pagination or cursor with deleting items in the list

I have a REST API that could GET, POST, PUT, DELETE models. My problem is when I paginate that with ajax call combining with DELETE operations. My problem comes after few steps list one page list ...
7
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4answers
293 views

What's best practice when putting an abstraction layer over an ORM?

When working with an ORM such as Entity Framework, I've fallen into a comfortable habit. Make an interface with get/add methods on it, put this on a "Repository" class then add a constructor to each ...
3
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2answers
347 views

Should I use nhibernate for a one row settings table

I am using nhibernate in a quite big project. The system has a settings table which has 10 columns and one row, there is always a row and it should not be deleted only modified. Concurrency can be a ...
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3answers
2k views

Proper Query Object Pattern - NHibernate

I was looking to an alternative to Repository Pattern and I've read about "Query object pattern" (http://lostechies.com/jimmybogard/2012/10/08/favor-query-objects-over-repositories/). However the ...
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1answer
84 views

Why would you use a Report Engine, if your application are modeled around ORM

For example, you use some MVC framework for your web application and for most of the time you are thinking in very object oriented way, and that is why you opted to use an ORM framework in the first ...
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3answers
407 views

Repository matrix pattern?

I'm trying really hard to refactor some of my legacy code in the project using best practices and design patterns + DDD so I'd love some feedback on an issue I'm currently having. Let's assume that I ...
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1answer
473 views

ORM: runtime proxies vs bytecode instrumentation

What are the benefits of using runtime proxies with an ORM provider like Hibernate or EclipseLink compared to bytecode instrumentation/enhancement? I know that bytecode instrumentation helps to ...
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633 views

Any “Gotchas” to using Entity Framework for Identity & Dapper for all other DB access in a .NET MVC application?

I'm firing up an MVC project in which I'd really like to use Dapper as my ORM, as I like to be as close to the database as possible for performance and SQL tweaking reasons, yet still have the power ...
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1answer
72 views

What should this interface contain?

I am creating a schema for Doctrine but first I'm creating interfaces, abstract classes (models) which will be extended by the entities. I have a PresentationInterface which contain getter and ...
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1answer
483 views

Accessing database from static and non-static methods

I'm currently building a REST API in PHP & MySQL, and now I'm stuck at how I should structure the classes and the database connection. Let's say I have a table in my database for movies. How ...
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2answers
57 views

Solutions To Partial ORM Retrieval

I have read the following question regarding whether it is best to use objects with fully or partially populated data members. The 3 suggestions were: that perhaps using a fully populated ORM model ...
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2answers
185 views

DDD using an ORM and a Active Directory Server for Persistence

With Domain Driven Design one would model out the domain. One would then use an ORM of some sort to take care of the persistence. Say you have a Product entity which has a Name, SKU and an Owner. This ...
2
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2answers
204 views

What's the correct approach to DAO layer in presence of ORM framework

I'm using JPA/Hibernate but probably it doesn't limit question. Currently I'm writing my data access code in my web controller classes. Thanks to JPA, in most cases this code is very simple, ...
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1answer
209 views

Finding next free IP in a network

I have an IP network and want to automatically find a free IP address to provision a new server. Due to frequent server additions/removals the used IPs might be quite fragmented over the whole address ...
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2answers
308 views

How do I do SQL Server mapping with a new Desktop application written in C#? [closed]

In 2 weeks I will be starting a new job as a software developer in a company that currently does not employ any professional programmers. My first task will be to rewrite a Excel/VBA application in C#...
6
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4answers
2k views

When is it necessary to use ORM tools? [closed]

I was raised in a part of web developmentland where the creation of websites is mostly synonymous with Wordpress, FTP, Joomla, and procedural code, instead of things like TDD, A/B testing, Doctrine, ...
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1answer
135 views

How to evaluate the performance of a Data Access Layer b/w two ORM's?

I am currently working on a project where I am going to replace the Data Access Layer from a custom ORM to Entity Framework.(The product is almost complete and mostly any changes that will follow ...
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1answer
145 views

What happens to database design process when ORM tools are used?

I have learned about database design, including normalization during my undergraduate course. When we have to model a database for a system, we can start with an ER model and then convert it to the ...
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2answers
205 views

Definition of the NHibernate Mapping by Code / EF Code First pattern?

Sub-questions: Does this pattern have a formal definition? Who invented it? Is it considered a DSL? The reason why I am asking is because I would like to better assess its applicability to non-...
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3answers
310 views

Limiting complexity in JPA programs Java/Hibernate

I've been working on a new application for some months now. It's my first big JPA program, and is still in the early stages. However, the complexity of my JPA object tree is becoming a growing problem....
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1answer
261 views

Initialize object from SqlDataReader

As of now, we have two different styles of object intializations based on SQL row in our codebase: public Config(SqlDataReader sdr) { for (int i = 0; i < sdr.FieldCount; i++) if (!sdr.IsDBNull(...
0
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1answer
263 views

Database object mapping, good practices [closed]

I think I've understood the basic idea behind object mapping but there is one gap in my knowledge base that I hope to fill now. First let me tell you what I understand out of the whole thing. I have ...
2
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1answer
508 views

Does ORM at any point become a “requirement” for RESTful API?

I've started building a RESTful API in PHP's Slim framework. The framework appealed to me because of its light-weight design and routing features. I am using PostgreSQL for the database. However, ...
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1answer
337 views

Implementing a NoSQL and RDBMS compatible DAO

What would be the correct way to design a DAO which implementation is first going to be targeting a MS SQL database with a STAR model, but yet, business requirements specify the application must be ...
0
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1answer
287 views

ActiveRecord equivalent in Java [closed]

My question is fairly simple.. What is the closest ORM to ActiveRecord that I'd be able to find for Java? In other words, in terms of thinking patterns and knowledge, with limted development time, ...
0
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1answer
321 views

Class Table Inheritance: do child tables need a primary key?

I'm using the Class Table Inheritance architecture with my application and have read Fowler. When mapping my database tables to classes in code, I've realized I have no need for an "ID" property on ...
3
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1answer
158 views

What TDD/BDD tests should be writen to test an ORM

So I'm writing an ORM for NodeJS and using Mocha + Chai to test it. What I want to know is, what tests I should write to it, insertion tests should also have a querying test so I can check if the ...
7
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3answers
231 views

How to model and store an entity which has “one or more” values

I'll use C# to design the model to be persisted Let's suppose I have the following entity: public class Episode { public int Id { get; set; } public string Title { get; set; } public ...
11
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2answers
1k views

Best practices for serialization of DDD aggregates

According to DDD domain logic should not be polluted with technical concerns like serialization, object-relational mapping, etc. So how do you serialize or map the aggregates' state without publicly ...
2
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0answers
241 views

Entity Framework and separating DAL from domain entities

If I have a normalized db, it's unlikely to map 1 to 1 with my domain entities. So I customize my EF entities to fit the domain. But now my EF entities are essentially my domain entities and my DAL is ...
2
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1answer
288 views

Creating/updating entity save strategy

Please note: although I'm talking about Java in this question, what I'm asking about here should really be language-agnostic. I am dabbling in OR/M for the first time, and have cooked up the ...