im just starting to learn LINQ and at the same time im working on a research project for school on using link to entities with oracle and DB2 im trying to find a tool or addon that i can use to test my result sets so that i can run a linq query and see the resulting data i have seen LINQ pad but it seems to be set up for microsoft sql server and compact is there a similar tool that i can use to test against alternate databases out there or a way to setup linq pad to be used with foreign databases
So you are just looking for a tool to see linq queries get executed, and their results?
If you want to take the "profiling" approach Entity Framework Profiler (http://efprof.com/) would do the trick. It allows you to see linq statements get executed, time spent querying, sql generated, as well as see the result set that is returned. Its not a test tool by any means... its free for 30 days and after that you will need to pay for a license.
I think you would be better off by using MS Unit Test framework and just validating the results programmatically.
Related
I'm using Entity Framework to generate sql queries. And DB admins send me queries which are too slow or not optimized. But in app are hundreds requests to DB and too hard to find right one.
Is it any possibilities to set label in query? I need it to find query faster than I do it now.
depends a little on your EF version ...
in EF6 for example you could take the command interception approach to modify all SQL statements EF generates ...
see https://www.entityframeworktutorial.net/entityframework6/database-command-interception.aspx
I am querying for values from a database in AWS sydney, (I am in new zealand), using stopwatch i measured the query time, it is wildly inconsistent, sometimes in the 10s of milliseconds and sometimes in the hundreds of milliseconds, for the exact same query. I have no idea why.
Var device = db.things.AsQueryable().FirstOrDefault(p=>p.ThingName == model.thingName);
things table only has 5 entries, I have tried it without the asqueryable and it seems to make no difference. I am using visual studio 2013, entity framework version 6.1.1
EDIT:
Because this is for a business, I cannot put a lot of code up, another time example is that it went from 34 ms to 400 ms
thanks
This can be related to cold-warm query execution.
The very first time any query is made against a given model, the Entity Framework does a lot of work behind the scenes to load and validate the model. We frequently refer to this first query as a "cold" query. Further queries against an already loaded model are known as "warm" queries, and are much faster.
You can find more information about this in the following article:
https://msdn.microsoft.com/en-us/library/hh949853(v=vs.113).aspx
One way to make sure this is the problem is to write a Stored Procedure and get data by it(using Entity Framework) to see if the problem is in the connection or in the query(Entity Framework) itself.
I am using LINQ to SQL for much of the data access layer and am trying to view and tune the underlying SQL used. Does anyone know a good mechanism to intercept the SQL used by C# LINQ and/or replace it with a more tuned query?
I highly recommend using LINQPad to analyze and optimize your LINQ. You can display generated SQL and check also how long certain query took.
You can also use it with existing project that uses Entity Framework. See more details here.
The DataContext itself has a Log property which is a TextWriter, using this you can write out to whatever you want be it the framework TraceClasses or something Like Log4Net or NLog
I am building a forum, and it has got 4 tables: Users, Threads, Comments, Topics.
I established the connection and the pages.. I started using the ADO.net way to insert data and select data..but then I found that to make more complex manipulations i need to know SQL. So I was looking for another way, and I found that I can open Visual Studio 2010, add Linq to SQL file that produced object relational designer. I read about how to write code, and I saw that I simply need to use a using statement with DataContext object with a simple code to update, add, delete rows in the tables.
I wanted to know, what are the advantages of using one way of querying over another?
ADO.NET gives you low level control over your queries. If query speed is going to be of importance, this is where you want to be. If you speed is not very important, but rapid development and an Object Relational Model is, LINQ to SQL is a safe bet.
I would recommend Linq to SQL over ADO.NET though.
Development is rapid and thinking in an ORM way is natural.
If your queries are too slow, using the .ExecuteQuery method will allow you to pass in a sql statement that you have optimized as if you were doing it in the ADO.NET way. I have had much success with Linq to Sql.
Also I would look at Entity Framework. It gives you more control over your objects and how they are implemented, used and handled than Linq.
LINQ to SQL is part of the ADO.NET family of technologies. It is based on services provided by the ADO.NET provider model. You can therefore mix LINQ to SQL code with existing ADO.NET applications and migrate current ADO.NET solutions to LINQ to SQL. The following illustration provides a high-level view of the relationship.
Refer to the following:
ADO.NET and LINQ to SQL
Advantages & Disadvantages of LINQ
Performance of LINQ to SQL over Normal Stored procedure
LINQ-to-SQL and Stored Procedures
LINQ to SQL is great in that it generates alot of the plumbing code for you. But it is basically the same as using straight up ADO.NET/SQL. To do more complex data manipulation in LINQ to SQL you have to know how write complex joins in LINQ just as you would in SQL.
Look into Entity Framework - it might give you a higher level of abstraction that you are looking for.
The two are on different abstraction levels. ADO.NET is the lowest level of data access in .NET. Anything else will build upon it.
Every abstraction should give you power to express higher-level concepts at the cost of lower level concepts.
If I sound like a philosopher it's because it's Friday.
In addition to Entity Framework, you can take a look at NHibernate (another .net Object Relational Mapper). It's been around longer than EF so it's a bit more mature, but it isn't developed by Microsoft if that matters to you.
LINQ-to-SQL had several ways, including a visualizer add-in, to view the generated SQL from an IQueryable.
I can't find the equivalent for Entity Framework 4. Nothing on StackOverflow, no blogs. How is it done?
Preferably, I'd like to be able to do it in code and without having to actually execute the query just to see it.
Thanks!
there are several approaches to looking at the sql.
Free
On the ObjectQuery do .ToTraceString() that will show u the sql generated for the query.
Download ef tracing provider written by one of the EF team members. EF Tracing Provider
Linq To Entities visualizer which you can download here.
LinqPad
Sqlserver profiler
Commercial
Efprof.com
If you can't get any of the other solutions to work, you could try using the SQL Server Profiler if you have access to the SQL Machine.
Within SQL Server Management Studio you can do the following:
Tools -> SQL Server Profiler.
Create a new Trace and run your code and you should see the queries come across. You can create some filters so you don't see the security / audit stuff which you probably don't care about.
Hi there is this visualizer...but I could not get it to work for me...you could try it..I would recommend LINQPad for viewing your queries you can setup your ef connection and execute your queries.