I need to see how subsonic generates the SQL Query string.
I either have Sql Profile listening on the database or if you're in debug mode with VS you can move the cursor over the linq statement and it is in the tooltip.
THIS WILL WORK FOR SUBSONIC 2.X ONLY
When you create query like this:
var q = new Select()
.From(TableName.Schema)
.Where(TableName.Columns.ColumnName)
.IsEqualTo(SOME_VALUE).Or(TableName.Columns.OtherColumn)
.IsEqualTo(OTHER_VALUE)
......;
you can dump SQL Query to somewhere or break after this line to view it in Debug Visualizer:
Debug.WriteLine(q.SQLCommand);
Related
Hello for demonstration purposes I trimmed out my actual sql query.
I have a SQL query
SELECT *
FROM dbdev.training.courses
where dbdev is my DEV database table name. When I migrate to TEST env, I want my query to dynamically change to
SELECT *
FROM dbtest.training.courses
I tried using input parameters like {env: p('db_name')} and using in the query as
SELECT * FROM :env.training.courses
or
SELECT * FROM (:env).training.courses
but none of them worked. I don't want my SQL query in properties file.
Can you please suggest a way to write my SQL query dynamically based on environment?
The only alternative way is to deploy separate jars for different environments with different code.
You can set the value of the property to a variable and then use the variable with string interpolation.
Warning: creating dynamic SQL queries using any kind of string manipulation may expose your application to SQL injection security vulnerabilities.
Example:
#['SELECT * FROM $(vars.database default "dbtest").training.courses']
Actually, you can do a completely dynamic or partially dynamic query using the MuleSoft DB connector.
Please see this repo:
https://github.com/TheComputerClassroom/dynamicSQLGETandPATCH
Also, I'm about to post an update that allows joins.
At a high level, this is a "Query Builder" where the code that builds the query is written in DataWeave 2. I'm working on another version that allows joins between entities, too.
If you have questions, feel free to reply.
One way to do it is :
Create a variable before DB Connector:
getTableName - ${env}.training.courses
Write SQL Query :
Select * from $(getTableName);
I have a table like T1 with columns C1 and C2. I have the dbml with this table T1.
I want to generate the script for Insert/Update/delete.
For eg:
I don't want datacontext to excute the task.
db.T1.InsertOnSubmit(T);
db.SubmitChanges();
Instead I want the script alone.
INSERT INTO
[DB].[dbo].[T1]("C1","C2")
Values
("abc","abc")
There's a few things you could try:
You could set up a test class that calls all of the methods from which you'd like to have the SQL, and then use SQL Server Profiler to capture the SQL executed
Similar to above, but instead of using the Profiler, you could set db.Log = Console.Out to view the generated SQL in a console application
Use LINQPad to generate your DB context; it allows you to see the generated SQL by switching from the "Results" tab to the "SQL" tab
I am a SQL Server DBA for a company that sells an ASP.NET MVC3 application that uses LINQ and Entity Framework 4 for all database access. When I find an inefficient query in my SQL Server's plan cache that was generated by LINQ, I would like to be able to find that LINQ statement in the source code so that I can optimize it. What is the best way to find the LINQ that generated a given SQL statement?
For example, is there any way to put an entry in a config file or decorate the code somehow so that the class and method name or the LINQ statement itself are included as comments in the generated SQL?
The commercial tools ORM Profiler, Entity Framework Profiler or Hugati Query Profiler will both give you a stack trace for the methods which generated the SQL. That makes it fairly easy to find the LINQ in code, though it isn't displayed directly.
These tools also have the advantage that they make it easy to find inefficient queries amongst the many other SQL statements executed by the app.
Although it is not a free tool, this may provide the information you need:
http://efprof.com/
There is also a less expensive tool described here, which I have not used, but it looks very promising:
http://huagati.blogspot.com/2010/06/entity-framework-support-in-huagati.html
http://www.huagati.com/L2SProfiler/
I bet Entity Framework Profiler (http://efprof.com/) would help you out. The workflow is very different from what you asked for (which would be pretty cool BTW). It is a good tool, and is worth a look even if it's not your final solution.
Good luck!
If you have access to the ASP.NET code where the LINQ code is you can more or less know which query you are looking for, copy it into a freeware tool called LINQPad and run it directly there to get the generated SQL statements. http://www.linqpad.net/
You need first get the LINQ queries on your .net code, create a connection to your datasource, paste the Linq code in new queries and run them. You will get the SQL Query generated from the LINQ code.
For example:
from e in ETUSERs
where e.LoginName.Contains("a")
orderby e.LoginName
select e
SQL Results Tab:
-- Region Parameters
DECLARE #p0 VarChar(1000) = '%a%'
-- EndRegion
SELECT [t0].[UserID], [t0].[UsrFirstName], [t0].[UsrLastName], [t0].[LoginName], [t0].[Location], [t0].[Password], [t0].[UsrEmail], ...
FROM [ETUSER] AS [t0]
WHERE [t0].[LoginName] LIKE #p0
ORDER BY [t0].[LoginName]
This is probably not exactly what you are looking for, but it is worth knowing about this tool since it is very helpful to quickly test LINQ queries. There you can quickly edit and run to improve the code without recompiling the whole stuff.
I don't think you can modify the generated SQL easily but what you can do is to get the generated SQL before sending the query to the database.
So you can log every query in a separate textfile with timestamp and source code context information. But that means to modify each place in your source where LINQ queries are sent to the database. Maybe there is an extension point somewhere in the DataContext class for simplifying this.
Anyway here is the code to get the corresponding sql query for a LINQ query:
YourDataContext dc = new YourDataContext();
IQueryable<YourEntityClass> query =
from e in dc.YourEntities
where ...
select e;
string command = dc.GetCommand(query).CommandText;
Currently I use a block of code like this, to fetch a set of DB objects with matching IDs.
List<subjects> getSubjectsById(List<long> subjectIDs){
return ctx.tagSubjects.Where(t => subjectIDs.Contains(t.id)).ToList();
}
But this is really inefficient, because it requires the entire table to be read from the database and then filtered inside of C#.
What I would rather do would be something the equivelent of:
SELECT * FROM subjects WHERE subjects.id IN (1,2,3,4,5,...);
The big difference is that in the first example the filtering is happening inside the C# code, and in the second the filtering is done on the SQL server (where the data is).
Is there a [better] way to do this with LINQ?
Where did you find out that it downloads the entire table from SQL Server?
I'm sure it does what you want. It translates the query to a parameterized IN clause like:
... IN (#p1, #p2, #p3)
and passes the contents of the list as values to those parameters. You can confirm this with tools such as SQL Profiler and LINQ to SQL debugger visualizer or set the DataContext.Log property to console (before executing the query) and read the generated SQL:
dataContext.Log = Console.Out;
I get a Antlr.Runtime.NoViableAltException thrown when trying to run the following query in NHibernate.
IQuery query = session.CreateQuery("from <table> where 1 in (select <column>.STIntersects(geography::STGeomFromText('POINT(:longitude :latitude)', 4326)))");
I'm setting longitude and latitude in setQuery.
my assumption is the :: in calling geography::STGeomFromText... because it's thinking it's a query parameter. Is there a way to escape the :?
This query works in my SQL Manager Studio.
Thanks!
Does NHIbernate support the STIntersects method ?
What you could do, is let NHibernate execute a (native) SQL query, like this:
ISQLQuery query = session.CreateSQLQuery ("your sql statement goes here");
query.AddEntity (typeof(TheEntityTypeThatYouWant));
var result = query.List<TheEntityTypeThatYouWant>();
See this post for some more info: Using SQL Server 2008 Geography types with nHibernate's CreateSQLQuery
Just to share what I ended up doing was taking the ADO connection out of the NHibernate session, performing a SqlCommand directly and manually built my Model objects from the results. It sucks, but it works. The connection still managed by NHibernate correctly.