Where can I get good tutorial on Entity framework with Stored Procedure in MVC framework?
Is it better to use Enterprise library in this case when I have almost everything written in the stored procedure.
Note: I am using stored procedure because they are really very complex and some of them is over 1000 lines.
MVC is in this case absolutely not related. The way how you call stored procedure from EF will be still the same. I guess you want to use stored procedures without actually using entities and linq-to-entities (main EF features), don't you? Generally you need:
EDMX file (ado.net entity data model) where you run update from database and add all stored procedures you want to use. EDMX file also generates derived ObjectContext and all entities by default.
Next you must go to Model Browser and create Function import for each procedure. Function import will create method on the derived ObjectContext which will allow you call the stored procedure as any other .net method.
During function import you will have to create complex type (it can happen automatically) for result set returned from stored procedure.
You also don't have to use function imports at all and you can execute procedures directly by calling either:
objectContext.ExecuteSqlCommand("storedProcedureName", SqlParameters) for SPs not returning record set
objectContext.ExecuteStoreQuery<ResultType>("storedProcedureName", SqlParameters) for SPs returning record set. ResultType must have properties with same names as columns in result set. It can work only with flat types (no nested objects).
There are some limitations when using stored procedures:
Entity framework doesn't like stored procedures which returns dynamic result sets (based on some condition result set has different columns)
Entity framework doesn't support stored procedures returning multiple result sets - there are EFExtensions which does but it is more like doing ADO.NET directly.
If you are using Entityframwork Code-first,This way you can Use your stored-Procedure, In this Example I have four Input parameters.
var startDateTY = masterSales.PolicyStartDate;
var endateTY = masterSales.PolicyEndDate;
var startDatePY = masterSales.PolicyStartDate.Value.AddYears(-1);
var endatePY = masterSales.PolicyEndDate.Value.AddYears(-1);
var spParameters = new object[4];
spParameters[0] = new SqlParameter()
{
ParameterName = "startDateTY",
Value = startDateTY
};
spParameters[1] = new SqlParameter()
{
ParameterName = "endateTY",
Value = endateTY
};
spParameters[2] = new SqlParameter()
{
ParameterName = "startDatePY",
Value = startDatePY
};
spParameters[3] = new SqlParameter()
{
ParameterName = "endatePY",
Value = endatePY
};
var datalist = objContext.Database.SqlQuery<vMasterSalesAgentReport>("dbo.usp_GetSalesAgentReport #startDateTY,#endateTY,#startDatePY,#endatePY", spParameters).ToList();
store = "sp_selectmark #regid='" + id + "'";
var st = db.ExecuteStoreQuery<Sp>("exec " + store).ToList();
GridView1.DataSource = st;
GridView1.DataBind();
or
string store = "";
store = "sp_inserttbreg #name='" + regobj.name + "',#age='" + regobj.age + "',#place='" + regobj.place + "',#gender='" + regobj.gender + "',#email='" + regobj.email + "',#fon='" + regobj.fon + "'";
Related
i am using viewmodel to display data from two tables (Eta and Voyage) and i have used viewmodel name as 'EtaVoyage'.The problem is when i use this query, it gives me this error
Additional information: Object reference not set to an instance of an object.
var Test = db.Etas.AsEnumerable().Select(v => new EtaVoyage()
{
ShippingAgent = v.ShippingAgent,
VesselInformation = v.VesselInformation,
Port = v.Port,
CPort = v.CPort,
EtaDate = v.EtaDate,
GoodsCarried = v.VoyageDetails.FirstOrDefault().GoodsCarried,
VoyagePurpose = v.VoyageDetails.FirstOrDefault().VoyagePurpose
}).ToList();
return View(Test);
But when i comment the last two fields related to voyagedetails, it is working fine.
var Test = db.Etas.AsEnumerable().Select(v => new EtaVoyage()
{
ShippingAgent = v.ShippingAgent,
VesselInformation = v.VesselInformation,
Port = v.Port,
CustomPort = v.CustomPort,
EtaDate = v.EtaDate,
// GoodsCarried = v.VoyageDetails.FirstOrDefault().GoodsCarried,
// VoyagePurpose = v.VoyageDetails.FirstOrDefault().VoyagePurpose
}).ToList();
return View(Test);
i need to display these two columns too in the index page.
FirstOrDefault() might return null,
Enumerable.FirstOrDefault : Return Value
Type: TSource
default(TSource) if source is empty; otherwise, the first element in source.
Use
.Select(i=>i.GoodsCarried).FirstOrDefault()
....
GoodsCarried = v.VoyageDetails.Select(i=>i.GoodsCarried).FirstOrDefault(),
VoyagePurpose = v.VoyageDetails.Select(i=>i.VoyagePurpose).FirstOrDefault()
}).ToList();
The collection v.VoyageDetails must not contain any items, and therefore FirstOrDefault is returning the default (null for reference types). You can handle this special case separately, or, since you seem to just be flattening a collection, you can use a null-conditional operator to set GoodsCarried and VoyagePurpose to null when FirstOrDefault returns null.
GoodsCarried = v.VoyageDetails.FirstOrDefault()?.GoodsCarried,
VoyagePurpose = v.VoyageDetails.FirstOrDefault()?.VoyagePurpose
Note it is also possible that:
v.VoyageDetails itself is null, depending on how your class is initialized and data is loaded. If this is expected, you may need to handle this case as well. Again with the null-conditional operator:
GoodsCarried = v.VoyageDetails?.FirstOrDefault()?.GoodsCarried,
VoyagePurpose = v.VoyageDetails?.FirstOrDefault()?.VoyagePurpose
If you are using an ORM such as Entity Framework, the VoyageDetails collection is not eagerly loaded, it may simply not be retrieving the data for you. If this applies, you need to explicitly load the data in the collection. In Entity Framework this is done with an Include call. Note your AsEnumerable() call will stop Linq-To-Sql from optimizing this into a single query, but I assume this is intentional:
db.Etas.Include(x => x.VoyageDetails).AsEnumerable().Select(...)
I want to get list of records from an entity model (I'm using EF version 5) with a particular accountID. I'm being supplied with the tableName string (this has to be dynamic) and the accountID. I'm trying the following 2 methods but none of them is working (giving me errors on the IQueryable object 'table':
PropertyInfo info = _db.GetType().GetProperty(tableName);
IQueryable table = info.GetValue(_db, null) as IQueryable;
var query = table.Where(t => t.AccountID == accID)
.Select(t => t);
List <object> recList = ( from records in table
where records.AccountID == accID
select records).ToList<object>();
The var query = table.Where(....).Select(...) is the correct move as it allows reflection for the query builder at runtime. However, t.AccountID is an error because of the type of t remains unknown.
I've previously used a similar approach in LINQ to SQL, using System.Linq.Expressions.Expression, e.g.:
// NOT TESTED
var table=context.GetTable(dynamicTableName);
var theT=table.Experssion; // actually, I forget. DynamicExpression or MemberBinding? or
var theField=Expression.Field(theT, "AccountID"); // or dynamic name
var query=table.Where(Expression.Equal(theField, accID);
var recList=query.ToList<object>();
If your object has a common interface there is a simpler syntax:
IQueryable<MyInterface> table = context.GetTable("table") as IQueryable<MyInterface>;
var recList=from r in table
where table.AccountID == ac // if your AccountID is on MyInterface
select table;
If you only have a few tables to support, you could do this as well:
IQueryable<MyInterface> table;
if("table1"==tableName)
table=_db.table1
elseif("table2"==tableName)
table=_db.table2
elseif("table3"==tableName)
table=_db.table3
else
throw exception
I built a DynamicRepository for a project I am working on. It uses generic methods exposed through EF along with dynamic linq. It might be helpful to look at that source code here:
https://dynamicmvc.codeplex.com/SourceControl/latest#DynamicMVC/DynamicMVC/Data/DynamicRepository.cs
You can query the entity framework metadata workspace to get the type for a given table name. This link might help:
Get Tables and Relationships
An old question for Linq 2 Entities. I'm just asking it again, in case someone has came up with the solution.
I want to perform query that does this:
UPDATE dbo.Products WHERE Category = 1 SET Category = 5
And I want to do it with Entity Framework 4.3.1.
This is just an example, I have a tons of records I just want 1 column to change value, nothing else. Loading to DbContext with Where(...).Select(...), changing all elements, and then saving with SaveChanges() does not work well for me.
Should I stick with ExecuteCommand and send direct query as it is written above (of course make it reusable) or is there another nice way to do it from Linq 2 Entities / Fluent.
Thanks!
What you are describing isnt actually possible with Entity Framework. You have a few options,
You can write it as a string and execute it via EF with .ExecuteSqlCommand (on the context)
You can use something like Entity Framework Extended (however from what ive seen this doesnt have great performance)
You can update an entity without first fetching it from db like below
using (var context = new DBContext())
{
context.YourEntitySet.Attach(yourExistingEntity);
// Update fields
context.SaveChanges();
}
If you have set-based operations, then SQL is better suited than EF.
So, yes - in this case you should stick with ExecuteCommand.
I don't know if this suits you but you can try creating a stored procedure that will perform the update and then add that procedure to your model as a function import. Then you can perform the update in a single database call:
using(var dc = new YourDataContext())
{
dc.UpdateProductsCategory(1, 5);
}
where UpdateProductsCategory would be the name of the imported stored procedure.
Yes, ExecuteCommand() is definitely the way to do it without fetching all the rows' data and letting ChangeTracker sort it out. Just to provide an example:
Will result in all rows being fetched and an update performed for each row changed:
using (YourDBContext yourDB = new YourDBContext()) {
yourDB.Products.Where(p => p.Category = 1).ToList().ForEach(p => p.Category = 5);
yourDB.SaveChanges();
}
Just a single update:
using (YourDBContext yourDB = new YourDBContext()) {
var sql = "UPDATE dbo.Products WHERE Category = #oldcategory SET Category = #newcategory";
var oldcp = new SqlParameter { ParameterName = "oldcategory", DbType = DbType.Int32, Value = 1 };
var newcp = new SqlParameter { ParameterName = "newcategory", DbType = DbType.Int32, Value = 5 };
yourDB.Database.ExecuteSqlCommand(sql, oldcp, newcp);
}
I am trying to execute a user-defined Oracle function that returns a RefCursor using ODP.NET. Here is the function:
CREATE OR REPLACE FUNCTION PKG.FUNC_TEST (ID IN TABLE.ID%type)
RETURN SYS_REFCURSOR
AS
REF_TEST SYS_REFCURSOR;
BEGIN
OPEN REF_TEST FOR
SELECT *
FROM TABLE;
RETURN REF_TEST;
END;
/
I can call this function in Toad (select func_test(7) from dual) and get back a CURSOR. But I need to get the cursor using C# and ODP.NET to fill a DataSet, but I keep getting a NullReferenceException - "Object reference not set to an instance of an object". Here is what I have for that:
OracleConnection oracleCon = new OracleConnection(ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString);
OracleCommand sqlCom = new OracleCommand("select func_test(7) from dual", oracleCon);
sqlCom.Parameters.Add("REF_TEST", OracleDbType.RefCursor, ParameterDirection.ReturnValue);
OracleDataAdapter dataAdapter = new OracleDataAdapter();
dataAdapter.SelectCommand = sqlCom;
DataSet dataSet = new DataSet();
dataAdapter.Fill(dataSet); //FAILS HERE with NullReferenceException
I was able to find lots of info and samples on using stored procedures and ODP.NET, but not so much for returning RefCursors from functions.
EDIT: I do not want to explicitly add input parameters to the OracleCommand object (i.e. sqlCom.Parameters.Add("id", OracleDbType.Int32,ParameterDirection.Input).Value = 7;) as that makes it difficult to implement this as a generic RESTful web service, but I'm reserving it as my last resort but would use stored procedures instead.
Any help is much appreciated!
I think you are missing the sqlCom.ExecuteNonQuery();
also, instead of running the select func_test(7) from dual; lets switch it to run the function and pass in the param
OracleConnection oracleCon = new OracleConnection(ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString);
// Set the command
string anonymous_block = "begin " +
" :refcursor1 := func_test(7) ;" +
"end;";
//fill in your function and variables via the above example
OracleCommand sqlCom= con.CreateCommand();
sqlCom.CommandText = anonymous_block;
// Bind
sqlCom.Parameters.Add("refcursor1", OracleDbType.RefCursor);
sqlCom.Parameters[0].Direction = ParameterDirection.ReturnValue;
try
{
// Execute command; Have the parameters populated
sqlCom.ExecuteNonQuery();
// Create the OracleDataAdapter
OracleDataAdapter da = new OracleDataAdapter(sqlCom);
// Populate a DataSet with refcursor1.
DataSet ds = new DataSet();
da.Fill(ds, "refcursor1", (OracleRefCursor)(sqlCom.Parameters["refcursor1"].Value));
// Print out the field count the REF Cursor
Console.WriteLine("Field count: " + ds.Tables["refcursor1"].Columns.Count);
}
catch (Exception e)
{
Console.WriteLine("Error: {0}", e.Message);
}
finally
{
// Dispose OracleCommand object
cmd.Dispose();
// Close and Dispose OracleConnection object
con.Close();
con.Dispose();}
this is based on the example ODP that can be found # %ora_home%\Client_1\ODP.NET\samples\RefCursor\Sample5.csproj
If you want to avoid (for better or worst!) the custom built param collection for each proc/function call you can get around that by utilizing anonymous blocks in your code, I have ammended (once again untested!) the code above to reflect this technique.
Here is a nice blog (from none other than Mark Williams) showing this technique.
http://oradim.blogspot.com/2007/04/odpnet-tip-anonymous-plsql-and.html
I'm trying to map OleDb parameters to an Oracle Function. I was able to do this using the System.Data.Oracle namespace but then found that this is depricated, so I thought i would re-write it as OldDb to avoid installing the Oracle Provider.
I have defined the following oracle function as an example:
create function GetImagePath (AIRSNumber in number)
return varchar2
is
begin
return '\\aiimg524\images\Ofndrtrk\2010\01\0kvrv1p000lcs74j';
end;
and I'm calling it using the following code:
using (var command = new OleDbCommand())
{
command.Connection = con;
command.CommandText = ConfigurationManager.AppSettings[OTRAK_PHOTO_FUNC];
command.CommandType = CommandType.StoredProcedure;
string parm = ConfigurationManager.AppSettings[OTRAK_PHOTO_PARM];
command.Parameters.Add(parm, OleDbType.Decimal); // maps to oracle Number
command.Parameters[parm].Direction = ParameterDirection.Input;
command.Parameters[parm].Value = airsNumber;
command.Parameters.Add(RETURN_VALUE, OleDbType.Variant); // maps to Oracle varchar2
command.Parameters[RETURN_VALUE].Direction = ParameterDirection.ReturnValue;
try
{
con.Open();
command.ExecuteNonQuery();
path = command.Parameters[RETURN_VALUE].Value.ToString();
}
I tried a bunch of different OleDB types for the parameter and the return value. the current attempt is from a mapping table i found on the web that said number = decimal and varchar2 = variant. I'm about to try every permutation of types in the enum and wanted to ask for help. the not so useful error message i get is:
[System.Data.OleDb.OleDbException] = {"ORA-06550: line 1, column 7:\nPLS-00306: wrong number or types of arguments in call to 'GETIMAGEPATH'\nORA-06550: line 1, column 7:\nPL/SQL: Statement ignored"}
This actually had nothing to do with the type of the parameters but the order. Using the OleDb provider for Oracle does not respect the names of the parameters in the parameter collection but rather the order that the parameters are added. Wwhen calling an oracle function, the return value is a free parameter that must be declared first. by adding my return value parameter and then the actual function parameter things started working.
using the command.Parameters.AddWithValue(parm, value) also simplifies things a bit.