I have a stored procedure which returns a 0 or a 1 depending on whether or not a specified email address exists in my database:
CREATE PROCEDURE [DatabaseSchema].[EmailAddressIsDuplicate] (#emailAddress nvarchar(255))
AS
BEGIN
SET NOCOUNT ON;
IF EXISTS(
SELECT *
FROM [DatabaseSchema].[EmailUpdatesRegistrant]
WHERE EmailAddress = #emailAddress
)
RETURN 1
ELSE
RETURN 0
RETURN 0
END
GO
And I'm trying to derive the results of this stored procedure from an Entity Framework 6 database context:
using (DatabaseContext dbContext = new DatabaseContext())
{
ObjectParameter param = new ObjectParameter("emailAddress", typeof(bool));
var result = dbContext.EmailAddressIsDuplicate(emailAddress);
}
I'm getting lots of errors.
Error #1: Using the code above, var result is always set to -1.
Error #2: I tried navigated to Edit Function Import and set the Returns a Collection Of to a Boolean scalar value. This throws the following error:
The data reader returned by the store data provider does not have enough columns for the query requested.
Error #3: I went back and set the Edit Function Import return value to None. Then I tried the following code from this answer:
using (DatabaseContext dbContext = new DatabaseContext())
{
var p = new SqlParameter("#emailAddress", emailAddress);
var result = dbContext.Database.SqlQuery<bool>("DatabaseSchema.EmailAddressIsDuplicate", p);
}
No immediate errors thrown, but I have no idea whether or not I can derive useful data from var result. Trying to cast result to bool throws the following error:
Cannot convert type 'System.Data.Entity.Infrastructure.DbRawSqlQuery' to 'bool'
Any ideas on how I can see the results of this stored procedure (0 or 1)?
You could try adding an output parameter (#result) in the stored procedure signature:
CREATE PROCEDURE [DatabaseSchema].[EmailAddressIsDuplicate]
(#emailAddress nvarchar(255), #result bit out)
AS
BEGIN
SET NOCOUNT ON;
IF EXISTS(SELECT *
FROM [DatabaseSchema].[EmailUpdatesRegistrant]
WHERE EmailAddress = #emailAddress)
SET #result = 1
ELSE
SET #result = 0
RETURN #result
END
GO
(you'll have to re-define your EF Model Function definition accordingly)
using (DatabaseContext dbContext = new DatabaseContext())
{
ObjectParameter isDuplicate = new ObjectParameter("isDuplicate", typeof(bool));
var result = dbContext.EmailAddressIsDuplicate(emailAddress, isDuplicate);
bool emailIsDuplicate = (bool)isDuplicate.Value;.
}
If you want to call the stored procedure directly with an out parameter you could follow this suggestion:
Database.SqlQuery calling stored procedure that has multiple output parameters
REASON - The template builder for EF (including v6) incorrectly sets the SP up as returning an INT containing the row count rather than the return value because it incorrectly calls the wrong ObjectContext.ExecuteFunction (found in the template-generated class YourDatabaseEntities that is the child of the DBContext).
Why wrong ExecuteFunction? - The result set incorrectly says the row count of changed rows rather than the return value or output parameters because it calls a different ExecuteFunction that discards the results. The flyover intellisense hint of the ObjectContext.ExecuteFunction says "Executes a stored procedure ….; discards any results returned from the function; and returns the number of rows affected by the execution" rather than the usual "Executes a stored procedure …. with the specified parameters".
WHY -1: I believe the SET NOCOUNT ON is causing the SP to return no count result and that Microsoft's ExecuteFunction returns that as error code.
SP FIXES - 1) You have to comment out SET NOCOUNT ON .
2) You have to change stored procedure to do the SELECT command as last statement instead of the RETURN command.
SOLUTION FIX - 1) After fixing SP, delete SP from Function Imports folder and the Data Store's SP folder. 2) Reload the SP into the EDMX by using the "Update Model from Database" 3) Rebuild all of your data project where the EDMX resides. 4) Exit Visual Studio and return. 5) Rebuild overall solution.
See: Entity Framework (Database first) has incorrect return result from stored procedure
Implement the stored procedure in C# to a value using parameters.
Resource: https://msdn.microsoft.com/en-us/library/yy6y35y8(v=vs.110).aspx
This way, the values can be stored to a variable from the ExecuteReader.
Add the value to model similar to adding a value to a property. The stored procedure could be called from ActionResult. Though this may require adding the stored procedure to a separate layer, that simply runs the stored procedure and adds the value to model afterwards.
try this
CREATE PROCEDURE [DatabaseSchema].[EmailAddressIsDuplicate] (#emailAddress nvarchar(255))
AS
BEGIN
SELECT *
FROM [DatabaseSchema].[EmailUpdatesRegistrant]
WHERE EmailAddress = #emailAddress
SELECT ##ROWCOUNT
END
GO
using (DatabaseContext dbContext = new DatabaseContext())
{
var result = dbContext.Database.SqlQuery<int32>("exec DatabaseSchema.EmailAddressIsDuplicate {0}", emailAddress).FirstOrDefault();
}
Anything other 0 in the return value indicates there is a match and the number indicates the number of matches
Related
I have an entity, lets just call it "Entity", that I want to delete with a stored procedure. The "Entity" entity is relatively complex with a lot of related entities - Hence why, I want to use a stored procedure to delete the Entity.
CREATE PROCEDURE dbo.spDeleteEntity
#EntityId int,
#ServiceResult bit output
AS
BEGIN
.... Delete logic here ...
IF ##ERROR = 0
SET #ServiceResult = 1
ELSE SET #ServiceResult = 0
END
As you can see, the stored procedure takes in an EntityId for the entity, performs my delete logic, and returns a bit - Which in this case is my ServiceResult. Here the ServiceResult is "True"/1 if no errors occur while executing the query, and "False"/0 if errors occur. The problem is now, that I want to be able to execute this stored procedure from .NET Core. My Initial idea was to do something like this
public bool DeleteEntity(Entity Entity)
{
return _context.Entity.FromSqlRaw<bool>("spDeleteEntity {0}", Entity.Id);
}
I believe this doesn't work, because Entity Framework Core does not know what datatype it should expect. From what I can read, Entity Framework Core only accepts types of TEntity. So my question really is, how do I call a stored procedure with Entity Framework Core, so that I can pass an Id and get a bool value returned.
While in your case, you could simply RAISERROR in your procedure to indicate failure.;
try{
_context.Database.ExecuteSqlInterpolatedAsync($"spDeleteEntity {Entity.Id}");
return true;
}catch(...){
return false;
}
There is a way to pass sql parameters in / out of raw sql commands using EF Core with something like;
var entityId = new SqlParameter("#entityId", Entity.Id);
var result = new SqlParameter("#result", SqlDbType.Bit)
{ Direction = ParameterDirection.Output };
_context.Database.ExecuteSqlRaw("EXEC #result = spDeleteEntity #entityId", entityId, result);
return (bool)result.Value;
Call your stored procedure in the try catch and add your SqlParameter that you want to pass to sp like this :
try
{
using(var context = new SampleContext())
{
//Declare storedprocedure parameter
var Idp = new SqlParameter("#IdParam", "Idp");
//Call stored procedure(For async call use ExecuteSqlCommandAsync method)
context.Database.ExecuteSqlCommand("EXEC spName #IdParam", Idp);
}
Return true:
}
catch
{
Return false;
}
In this way if execution of sp occurred with error, it goes to catch and return false and if not it's return true.
Note: if you declare raiseerror in your storedprocedure, you can generates an error message and send it to your application try catch.
More details about raiseerror :
https://learn.microsoft.com/en-us/sql/t-sql/language-elements/raiserror-transact-sql?view=sql-server-ver15
I have the following part in the end of a SQL Server stored procedure:
if(#someValue < 0)
begin
SELECT #resultIsSuccess = 0
Return #resultIsSuccess
end
else
begin
SELECT #resultIsSuccess = 1
Return #resultIsSuccess
end
where #resultIsSuccess is of type bit.
So, basically I am returning a bool to indicate if the procedure yielded the intended result.
On the EF side, I configured the Function Import's return type as boolean.
When I call:
bool isSuccess = context.MyFunctionImport(arg1, arg2).FirstOrDefault().Value;
I get the following exception:
The data reader returned by the store data provider does not have
enough columns for the query requested.
What is the problem here?
If you are returning a value, you need a return parameter. Therefore you aren't using a datareader to get your value. You aren't selecting anything therefore you would need to have access to that return parameter.
Instead select your values to populate the datareader since you are probably getting an error when you try to read values from a noninstantiated datareader through EF.
if(#someValue < 0)
SELECT 0
else
SELECT 1
I'm unsure if return values are supported, reference, so you may be trying to do the impossible unless fixed in a newer version.
You have to keep in mind that you are NOT returning a bit datatype from your procedure. The return datatype of a stored procedure is int.
You could greatly simplify your code to a single line return statement.
return case when #someValue < 0 then 0 else 1 end
Then in your code you would need to parse the 0 or 1 to a boolean.
--EDIT--
Since you are looking for the first value you will need to use a select statement in your procedure. Something like this.
Select isSuccess = case when #someValue < 0 then 0 else 1 end
I am having a somewhat frustrating issue.
On the lower level: I want to be able to know whether an INSERT or UPDATE query in a proc was successful or not. I am not 100% sure if there is a status that is returned on all queries (apart from the SELECT). I know SQL Server gives a return type to all stored procs, and currently all mine have a return type of Integer.
On the middle level: In my repository, I want to use Entity Framework to call my stored procs and return the status as a converted (from int) boolean from the proc execution to my service.
On the higher level: I want to be able to use the returned boolean from my service to report back to an MVC controller on the task that was being performed.
On the most important layer of my issue, I have the following code:
public virtual ObjectResult<int> Proc_AddApprovalProcessor(string userId, string approverId, int approvalOrder)
{
return ((IObjectContextAdapter)this).ObjectContext.ExecuteStoreQuery<int>(
"EXECUTE [dbo].[Proc_AddApprovalProcessor] #userId, #approverId, #approvalOrder",
new SqlParameter { ParameterName = "userId", Value = userId },
new SqlParameter { ParameterName = "approverId", Value = approverId },
new SqlParameter { ParameterName = "approvalOrder", Value = approvalOrder }).FirstOrDefault();
}
Make sure your insert/update stored procedures end with the following line:
SELECT ##ROWCOUNT
Then examine the return code and check that it is 1 (or however many rows you were expecting to insert/update).
You can use ##ROWCOUNT server variable immediately after the insert/update query to check number of affected rows by using the insert/update operation.
declare #fName varchar(50) = 'my name',
#lName varchar(50) = 'your name'
INSERT INTO myTable(fName,lName) values(#fName,#lName)
SELECT ##ROWCOUNT --> 0 - means no rows affected/nothing inserted or updated
--> 1 - means row has been inserted or updated successfully
if you are using transaction then have to use the below code to return the transaction count.
return ##TRANCOUNT;
I have a method that will return the bare min results from a sproc to fill a select menu. When I want the bare min results I pass bool getMin = true to the sproc, and when I want the complete record I pass bool getMin = false.
This is causing the Entity FrameWork error of "The data reader is incompatible with the specified"
The most relevant portion of the error
{"Message":"An error has occurred.","ExceptionMessage":"The data reader is incompatible with the specified 'CatalogModel.proc_GetFramingSystems_Result'. A member of the type, 'FrameType', does not have a corresponding column in the data reader with the same name.","ExceptionType":"System.Data.EntityCommandExecutionException",
Obviously the error is telling me that when the data reader attempted to set the property 'FrameType' that is was not in the query results.
Now I understand the error, what I am wanting to know is that am I goning to have t split up this sql sproc into two sprocs or is there a work around for this?
My function below
public static IEnumerable<IFramingSystem> GetFramingSystems(int brandID, string frameType, string glazeMethod, bool getMin)
{
using (CatalogEntities db = new CatalogEntities())
{
return db.proc_GetFramingSystems(brandID, frameType, glazeMethod, getMin).ToList<IFramingSystem>();
};
}
My TSQL below
ALTER proc [Catelog].[proc_GetFramingSystems]
#BrandID INT,
#FrameType VARCHAR(26),
#GlazeMethod VARCHAR(7) ='Inside',
#getMin BIT = 0
as
BEGIN
SET NOCOUNT ON;
IF #getMin =0
BEGIN
SELECT c.ID,c.Name,c.Descr,c.FrameType,c.isSubFrame,
c.GlassThickness,c.GlassPosition,c.GlazingMethod,c.SillProfile
from Catelog.Component c
WHERE c.MyType ='Frame'
AND c.FrameType = #FrameType
AND c.GlazingMethod = #GlazeMethod
AND c.ID IN(
SELECT cp.ComponentID FROM Catelog.Part p JOIN
Catelog.ComponentPart cp ON p.ID = cp.PartID
WHERE p.BrandID = #BrandID
)
ORDER BY c.Name
END
ELSE
SELECT c.ID,c.Name,c.Descr
from Catelog.Component c
WHERE c.MyType ='Frame'
AND c.FrameType = #FrameType
AND c.GlazingMethod = #GlazeMethod
AND c.ID IN(
SELECT cp.ComponentID FROM Catelog.Part p JOIN
Catelog.ComponentPart cp ON p.ID = cp.PartID
WHERE p.BrandID = #BrandID
)
ORDER BY c.Name
SET NOCOUNT OFF;
END;
To me it seems that both branches of the IF return different data, the first branch returns 9 columns where the second - only three. I believe the EF can't reflect the IFramingSystem from the latter. Specifically, the column FrameType (and 5 other columns) are obviously missing:
...
SELECT c.ID,c.Name,c.Descr <- where are the remaining columns
from Catelog.Component c
...
I understand this is an old post; but, I wanted to share what I learned tonight about this. What I found that the 'most relevant portion of the error message is stating' is this.
db.proc_GetFramingSystems(brandID, frameType, glazeMethod, getMin).ToList<IFramingSystem>();
is expecting a column to be returned from the stored procedure with the alias of 'FrameType'.
I ran into this when I created a POCO (plain old clr object) class of my table with more programmer friendly names. Instead of a strongly typed name of say 'email_address', I wanted 'EmailAddy' and so forth. I created a mapped class stating this among other mapped columns.
this.Property(t => t.EmailAddy).HasColumnName("email_address");
Although this is necessary for other parts of EF to work, the mapping class is not referenced when executing a db.SqlQuery.
So, when the code below executes
var a = new SqlParameter("#fshipno", shipno);
return _context.db.SqlQuery<EmailList>("exec spGetEmailAddy #fshipno", a).ToList();
It generated the same error except instead of 'FrameType', it mentioned 'EmailAddy'.
The fix... I had to alias the 'email_address' column in my stored procedure to 'EmailAddy' to get it to map the returned dataset to my POCO.
EDIT: I have found that this only works if your method is returning an IEnumerable:
public IEnumerable<myPOCO> GetMyPoco()
You will get the same error message if you are attempting to return a single POCO object.
public myPOCO GetMyPoco()
If you are inserting/deleting/updating (these are considered by EF as 'non-query'), and can be called by our code using
MyDbContext.Database.ExecuteSqlCommand(insert into Table (Col1,Col2) values (1,2));
But if are doing select query for a raw SQL statement, then use
MyDbContext.DbSet<Table_name>.SqlQuery(select * from table_name).ToList();
or
MyDbContext.Database.SqlQuery(select * from table_name).ToList();
()
The SqlQuery() function, in EF, for strange reasons, throw exception Insert/delete/update operation. (The exception thrown is "A member of the type, does not have a corresponding column in the data reader with the same name.") But it has actually performed operation if you open your Sql Management Studio and check for the entries.
FYI http://www.entityframeworktutorial.net/EntityFramework4.3/raw-sql-query-in-entity-framework.aspx
QUESTION
How do I access the 'Results', 'Messages', and 'Return Value' of a Stored Procedure using Entity Framework 4.4 and C# 4.0?
Below is the Stored Procedure that takes three parameters. One way or another when I run the Store Procedure I should, I hope, be able to access all three values for 'Results', 'Messages', and 'Return Value'.
Can someone help me figure out how to do that with EF? Using the code that is generated out of EF all I seem to be able to access is the 'Results' of the query ( returned rows )
Stored Procedure
USE [THIS_DB]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[THIS_PROCEDURE]
#FIRST_PARAM CHAR(17) = NULL,
#SECOND_PARAM CHAR(2) = NULL,
#THIRD_PARAM CHAR(5) = NULL
AS
BEGIN
SET NOCOUNT ON;
DECLARE #ReturnValue INT = 0;
IF COALESCE(#SECOND_PARAM, 'XX') NOT IN ('XX', 'YY')
BEGIN
RAISERROR('Invalid #SECOND_PARAM value: %s; #SECOND_PARAM mXXt be XX or YY.', 2, 1, #SECOND_PARAM ) WITH SETERROR;
SET #ReturnValue = -50100;
END
IF COALESCE(#SECOND_PARAM, 'XX') = 'YY'
BEGIN
RAISERROR('#SECOND_PARAM value: %s; YY is valid, but currently is not supported, returning XX results.', 2, 1, #SECOND_PARAM) WITH SETERROR;
SET #ReturnValue = -50105;
END
IF COALESCE(#THIRD_PARAM, 'XX-EN') NOT IN ('XX-EN')
BEGIN
RAISERROR('Invalid #THIRD_PARAM value: %s; #THIRD_PARAM mXXt be XX-EN.', 2, 1, #THIRD_PARAM) WITH SETERROR;
SET #ReturnValue = -50101;
END
SELECT DISTINCT
THESE.VALUES
FROM dbo.THIS_TABLE
WHERE THESE.CONDITIONS;
IF ##ROWCOUNT = 0
BEGIN
DECLARE #SP_MATCHCOUNT INT
EXEC #SP_MATCHCOUNT = [dbo].[MATCHTABLE] #PATTERNH = #PATTERN
IF #SP_MATCHCOUNT > 0
BEGIN
RAISERROR('Mapping from HERE to HERE not found for PATTERN: %s.', 2, 1, #PATTERN) WITH SETERROR
SET #ReturnValue = -50103;
END
ELSE
BEGIN
RAISERROR('PATTERN Pattern not found for PATTERN: %s.', 2, 1, #PATTERN) WITH SETERROR
SET #ReturnValue = -50104;
END
END
RETURN #ReturnValue
END
CODE
public virtual ObjectResult<THIS_PROCEDURE_RESULT> THIS_PROCEDURE_METHOD(string FIRST, string SECOND, string THIRD)
{
var FIRST_PARAM = FIRST != null ?
new ObjectParameter("FIRST", FIRST) :
new ObjectParameter("FIRST", typeof(string));
var SECOND_PARAM = SECOND != null ?
new ObjectParameter("SECOND", SECOND) :
new ObjectParameter("SECOND", typeof(string));
var THIRD_PARAM = THIRD != null ?
new ObjectParameter("THIRD", THIRD) :
new ObjectParameter("THIRD", typeof(string));
return ((IObjectContextAdapter)this).ObjectContext.ExecuteFunction<THIS_PROCEDURE_RESULT>("THIS_PROCEDURE", FIRST_PARAM, SECOND_PARAM, THIRD_PARAM);
}
So, first things first :-) Just want to make sure we're on the same page before I answer the 3 parts of the question. EF is designed to be an ORM (object-relational-mapper). That means its purpose for being is to translate relational data to code objects (and vice-versa). The mechanism it uses for this is result sets (not return values). So most of the plumbing inside EF is specifically designed to operate on result sets, and also to automatically generate SQL for getting those result sets. However, since people requested it, EF now has the capability to execute stored procedures, but that ability is not comprehensive, and is sort of a side-effect to the main capabilities of the product. Having said that, EF does use ADO.NET under the covers, and that's where you are going to get your answers because ADO.NET does handle all your scenarios.
First problem - how to get results. EF will execute the SP in this case, and presumably, it's mapped to some object that has properties that match the result columns. That means that EF will create a collection (enumerable query result set to be more precise) of objects, each of which represents a row of data in the results. In your case, the return of your method is ObjectResult. ObjectResult is a collection of objects, and each item is of type THIS_PROCEDURE_RESULT, which in turn has a property for each mapped column of the result.
Second problem - how to get messages. If Raiserror is used with a certain range of severity, will cause ADO.NET to throw and exception (of type SqlException). EF will just just surface (pass through) that error. That SQLException instance will contain all the error & message information. To see it, you just have to catch the error:
try
{
// call EF SP method here...
}
catch(SqlException se)
{
Debug.WriteLine(se.Message);
}
catch(Exception e)
{
// all non-DB errors will be seen here...
}
However, if the Raiserror statement is of a warning or info severity, ADO.NET will not throw an exception. In that case, you have to use an event of the connection object to see info and warning messages from the databse. To do this in EF, you have to get the EntityConnection from the EF object context, and then get the Store Connection from the EntityConnection. If you are using SQL Server (SqlClient ADO.NET provider), this will be a SqlConnection instance. That instance contains an event called InfoMessage. You can hook up an event handler to that event to trap messages. More info here: http://support.microsoft.com/kb/321903
Last problem - how to get Return Value. This one is going to suck. Based on my first paragraph, EF isn't really designed to arbitrarily handle SP calls. While it will map result sets to object collections, it doesn't handle return values from SPs. You will have to use ADO.NET without the EF layer in order to access the Parameters collections of the SqlCommand object. One of the parameters is of parameter-type ReturnValue, and it will contain the return value itself.