I'm fairly new to LINQ and trying to find a more elegant way (other than ADO.Net) to query and manipulate data in a SQLite database. I'm using System.Data.SQLite and wondering if there is a DataContext class or a way to use DataContext class to work with SQLite.
I believe LINQPad uses the same assembly for its SQLite/MySQL driver and with it I can execute C# expressions like so:
from c in Collection
where c.Length > 3
select c
What can I do to use those same LINQ expressions with my SQLite databases in my applications?
System.Data.SQLite supports the ADO.NET Entity Framework, so you should be able to just add an Entity Framework mapping and point it to your SQLite connection.
http://sqlite.phxsoftware.com/sqlite.wmv
Basically, Linq-to-SQL as is only support SQL Server as its backend.
You need to look at some third-party extension, like:
DBLinq
LinqConnect
Those additional tools allow you to use Linq-to-SQL against a variety of backend database stores, including SQLite.
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.
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LINQ to SQL is the predecessor of Entity Framework and is obsolete now.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 was wondering about the use of the .NET entity framework with an embedded database solution. Right now, I only use the EF with SQL Server but for a new project I'm looking for alternate solutions. SQL Server Compact would be one solution, but are there other alternatives that I can use with EF? Preferably solutions that don't require complex installations?
The actual (although not the full one) list of ADO.NET Entity Framework providers is available here.
There is a couple of providers supporting Embedded MySQL - dotConnect for MySQL and MySQL Connector/NET and SQLite - dotConnect for SQLite and System.Data.SQLite.
If there is an EF provider for the embedded database, you should be able to plug it right into EF. Check with your embedded database provider to see if they have support for EF.
Third Party Provider Support for the Entity Frameworkhttp://blogs.msdn.com/adonet/archive/2008/08/11/third-party-provider-support-for-the-entity-framework-rtm.aspx
Would someone explain how to get LINQ working with Sqlite.
Here you have an SQL Linq provider for SQLite, and some other DBs
Joe Albahari's LINQPad now supports Sqlite: http://www.linqpad.net/Beta.aspx. The one LINQ tool to rule them all.
The link provided by CMS doesn't work anymore. I have used this one as it now seems to be baked into their SQL lite ADO .NET provider.
Unfortunately they still don't support the designer mode of VS for creating classes :(
Also be aware that SQL Server compact doesn't support the design mode for LINQ classes! However if you want to use the entity framework the designer does work for SQL lite and SQL Server compact :)
Yup there is a SqlLite Linq Provider as mentioned by CMS
Check out SQL server compact and it works well with Linq
There is another thread on SO which you should check
I would like to add that you can use Linq to Sql with SqlLite with a couple of stipulations:
You cannot use the Linq to Sql designer which means you have to hand roll your classes.
You have to be careful not to do certain operation which will result in Sql code which is not supported by SqlLite.
For example, you cannot use FirstOrDefault() in any of your Linq queries because it will result in something like:
select top 1 * from table where ...
Since SqlLite doesn't support the "top 1" syntax, you will gt a runtime Sql error.
Other than that, I have been using Linq to Sql with SqlLite with great success for basic CRUD operations.
You can use this: http://code.google.com/p/dblinq2007.
Although it looks like the project is still in Alpha stage, IMO it is actually very stable now. Of course if you have a huge project, it is better to consider using something else like MySQL or SQL Compact. I don't like SQL Server, because it is too bloated, and offers not many more functionalities over SQL Compact or MySQL
Check this provider:
SqlLite Linq Provider
Also you can consider using SQL Compact which has very good LINQ-to-SQL support.
On this time there is NO good tools to do this!
LINQ providers for SQLite all is in alpha stage (for example:dblinq2007). And it is very big risk to use it in commercial purpose! So maybe in future...
If you want ot use ADO.NET there is good ove: phxsoftware.