I want to retrieve rows from an oracle table and convert them into objects.
I am currently using a refcursor result and a datareader in c# to manually convert the rows to objects but this seems messy. Is their a better way of converting rows from a relational table to objects?
EDIT: The project I'm on is not using any ORM tools so unfortunately it is down to little old me to do the mapping!
You can use UDTs and utilize the new ODP functionality to get the data.
this is a walkthrough on getting started:
http://www.oracle.com/technology/obe/hol08/dotnet/udt/udt_otn.htm
while this is a bit more detailed:
http://download.oracle.com/docs/html/E10927_01/featUDTs.htm
but the real meat & potatoes are already installed on your computer after you install ODP in the Samples directory:
%ORA_HOME%\product\11.1.0\client_1\odp.net\samples\2.x\UDT
Utilizing UDTs has helped out our origination and the time response is great.
You could use an ORM like NHibernate, Fluent NHibernate, Linq To Sql, or Entity Framework. ORMs (Object Relational Mappers) exist to turn datatables into objects. You specify which table points to which class, along with which columns point to which members, and the ORM will cast rows into objects. The also take care of your normal CRUD operations, so as soon as you map the tables, you can start interacting with them.
Edit: If you are using .Net 3.5 or later, you get Linq To Sql and Entity Framework (they are included in .Net). If you can't use an ORM, you are stuck doing the casting yourself (essentially, you are the ORM in that case)
Related
I have a connexion to a service in which I only have access to synonyms (i.e., I cannot create any view, procedure, ...) and I intent to query data from them. I'm using ODP.NET managed driver to do so but until now I found nothing to achieve that. I'm left with hard-coding all the queries but before doing that I wanted to ask if it's possible somehow to map c# classes to oracle synonyms if that makes sense at all.
Thanks in advance!
Mapping c# classes to database entities is typically done with an object relational mapper like Entity Framework. Unfortunately, the Oracle provider for EF doesn't support synonyms (source).
Personally I would give a MicroORM like PetaPoco, NPoco or Massive a try.
All of those options give you the possibility to map query results to classes.
Is there a way to automap a query into a class in C# in order to strong type the query results? I don't want to access to query result with a DataTable, specifying manually the Column Name anymore.
There is couple of options:
EntityFramework - powerful and heavyweight. https://msdn.microsoft.com/en-us/library/aa937723(v=vs.113).aspx
Dapper - lightweight - mostly mapper https://www.codeproject.com/Articles/212274/A-Look-at-Dapper-NET
If you need only mapping of stored procedures, queries etc, Dapper is good way to go, as it's basically adding extension methods to connection object. It cannot create database etc as Entity Framework but it all really depends on needs.
My favourite question. Use QueryFirst. Write your SQL in the SQL editor window, syntax validated as you type, then QueryFirst will generate the C# wrapper to execute it, with strongly typed inputs and outputs. And there are numerous other benefits :-) SqlServer, MySql and Postgres support built in. Others easy to add. Disclaimer : I wrote QueryFirst.
You should take a look at AutoMapper. It's an easy and user-friendly way to map a DataTable to a List<object> of your specification.
You can find an article which talks about it (including sample code) here.
If you want to automize the process, you can use dynamic objects which don't require you to create specific classes for every DataTable that you're using.Hope this helped!
There is a helpful library on LINQ to DB
"LINQ to DB is the fastest LINQ database access library offering a simple, light, fast, and type-safe layer between your POCO objects and your database."
https://github.com/linq2db/linq2db
I know the benefit of the LINQ and I know use of it in .Net Application. I fill same thing there are providing as a Entity Framework.
So What's Major Difference between LINQ and Entity Framework?
LINQ could be applied to any data source: in-memory objects, XML, SQL, ...
Entity Framework could use LINQ to perform queries against a relational database.
LINQ to SQL is the predecessor of Entity Framework and is obsolete now.
Comparing EF and LINQ is incorrect. Both are different things and they often work together to give better developer experience (and productivity benefit).
LINQ is querying syntax/model that can be applied to any data source. EF provides one such data source.
They are somewhat similar, and can be used in a very similar way, code-wise, but they have some important differences. Note that "LINQ" is not the same thing as "LINQ to SQL"; the EF also uses LINQ. Some notable differences are:
LINQ to SQL is largely SQL Server only, not so much by design as by implementation. The EF is designed to support, and does support, multiple DBs, if you have a compatible ADO.NET provider.
Out of the box, LINQ to SQL has a very poor story for DB metadata changes. You have to regenerate parts of your model from scratch, and you lose customizations.
The EF supports model features like many-to-many relationships and inheritance. LINQ to SQL does not directly support these.
In .NET 3.5, LINQ to SQL had much better support for SQL-Server-specific functionality than the EF. This is mostly not true in .NET 4; they're fairly similar in that respect.
The EF lets you choose Model First, DB First, or Code First modeling. LINQ to SQL, out of the box, really only supports DB First.
SOURCE : Here
I totally agree with VinayC. You cannot really compare.
With Entity Framework, you will be able to have a whole representation of your database in your program. It will help you create classes corresponding to the database elements, connected together like they are in the database. You can after interact with elements of theses classes directly, and like this impact the database. You will have some representation of these classes diagram in visual studio. It's basically often simpler than working directly with the database elements, even if setting it up requires some effort.
The use of Linq is to perform queries on the data sources.
I am working on window application developed using SCSF and we are using sybase database. As practise we create typedataset in the .net project and then populate them using framework method and for all the sql statement we write stored procedure in the database.
So we have type dataset in memory so I am using linq to select records from datatable. Can I step one step further and use something related to Entity Framework?
Can it reduce my work? I don't have hands-on experience with Entity Framework but can you suggest something in this scenario?
Thanks,
Denish
Entity framework uses similar concepts as the type datasets except for:
The ability to have a class structure that is not exactly the same as the table structure (e.g. class hierarchy, splitting tables into multiple classes, joining tables into one class).
The ability to use LINQ to perform queries in the database instead of in memory.
Entity framework also lets you map results of stored procedures to classes and bring results into memory if you need to run a query that is faster in memory or not translatable to SQL.
For most SQL queries the LINQ to Entity will be effective enough, so you will probably end up writing less stored procedures.
You will have to learn how to use EF and LINQ effectively and use can use 3rd party tools such as Entity Framework Profiler to help you.
I have recently been trying to set up a .Net application which will connect to an oracle database using object relational data types, I would like to do this using the Linq-Sql framework, however when using tools such as DbLinq it does not seem to allow for the object relational data type.
So I was wondering if anyone knows a way to do this?
Thanks,
Alex.
Oracle has been working on, and is now beta-testing, their Entity Framework provider:
ODAC Entity Framework and LINQ Beta has arrived! Itincludes support for Entity Framework, LINQ to Entities, Model-First, Entity Data Model Wizard, and more.
They've even posted a tutorial using Model-First development.
According to their statement of direction, they plan to have this production-ready sometime in 2011.
I've been meaning to test this out but I haven't had the need to in any current projects. It's a shame -- a year or so back I would have really appreciated this ;-)
Let me know how it is!