There are several ways to use ADO.NET to call a stored procedure and to get back return values and return parameters, including:
Use a DataSet object to gather the returned rows and to work with these rows in addition to the return values and the return parameters.
Use a DataReader object to gather the returned rows, to move through these rows, and to gather return values and return parameters.
Use the ExecuteScalar method to return the value from the first column of the results' first row with the return values and the return parameters. This is most useful with aggregate functions.
Use the ExecuteNonQuery method to return only the return parameters and the return values. Any returned rows are discarded. This is most useful for executing action queries.
This article demonstrates the last three methods and uses both the SqlCommand and the OleDbCommand objects. Make sure that you copy only the code for the managed provider that you are using. If you are not sure which managed provider you should use, visit the following Microsoft Developer Network Web site:
.NET Data Providers
http://msdn.microsoft.com/en-us/library/a6cd7c08.aspx In each of the samples in this article, the parameters are added to the Parameters collection of the Command object. When you use the SqlCommand object, you do not have add the parameters in any particular order, but the parameters must have the correct name. When you use the OleDbCommand object, you must add the parameters in the correct order, and you cannot use the parameters by name.
Use DataReader to Return Rows and Parameters
You can use the DataReader object to return a read-only, forward-only stream of data. The information that the DataReader contains can come from a stored procedure. This example uses the DataReader object to run a stored procedure that has an input and an output parameter and then moves through the returned records to view the return parameters.
Create the following stored procedure on the server that is running Microsoft SQL Server:
Create Procedure TestProcedure
(
@au_idIN varchar (11),
@numTitlesOUT Integer OUTPUT
)
As
select A.au_fname, A.au_lname, T.title
from authors as A join titleauthor as TA on
A.au_id=TA.au_id
join titles as T
on T.title_id=TA.title_id
where A.au_id=@au_idIN
set @numTitlesOUT = @@Rowcount
return (5)
Use the Imports statement on the System and the System.Data namespaces so that you do not have to qualify declarations in those namespaces later in your code. You must use the Imports statement prior to any other declarations. Make sure to copy only the code for the provider that you have chosen.SQL Client
Imports System.Data.SqlClient
OLE DB Data Provider
Imports System.Data.OleDb
Add the following code to the Form_Load event:SQL Client
Dim PubsConn As SqlConnection = New SqlConnection & _
("Data Source=server;integrated security=sspi;" & _
"initial Catalog=pubs;")
Dim testCMD As SqlCommand = New SqlCommand & _
("TestProcedure", PubsConn)
testCMD.CommandType = CommandType.StoredProcedure
Dim RetValue As SqlParameter = testCMD.Parameters.Add & _
("RetValue", SqlDbType.Int)
RetValue.Direction = ParameterDirection.ReturnValue
Dim auIDIN As SqlParameter = testCMD.Parameters.Add & _
("@au_idIN", SqlDbType.VarChar, 11)
auIDIN.Direction = ParameterDirection.Input
Dim NumTitles As SqlParameter = testCMD.Parameters.Add & _
("@numtitlesout", SqlDbType.Int)
NumTitles.Direction = ParameterDirection.Output
auIDIN.Value = "213-46-8915"
PubsConn.Open()
Dim myReader As SqlDataReader = testCMD.ExecuteReader()
Console.WriteLine("Book Titles for this Author:")
Do While myReader.Read
Console.WriteLine("{0}", myReader.GetString(2))
Loop
myReader.Close()
Console.WriteLine("Return Value: " & (RetValue.Value))
Console.WriteLine("Number of Records: " & (NumTitles.Value))
OLE DB Data Provider
Dim PubsConn As OleDbConnection = New OleDbConnection & _
("Provider=sqloledb;Data Source=server;" & _
"integrated security=sspi;initial Catalog=pubs;")
Dim testCMD As OleDbCommand = New OleDbCommand & _
("TestProcedure", PubsConn)
testCMD.CommandType = CommandType.StoredProcedure
Dim RetValue As OleDbParameter = testCMD.Parameters.Add & _
("RetValue", OleDbType.Integer)
RetValue.Direction = ParameterDirection.ReturnValue
Dim auIDIN As OleDbParameter = testCMD.Parameters.Add & _
("@au_idIN", OleDbType.VarChar, 11)
auIDIN.Direction = ParameterDirection.Input
Dim NumTitles As OleDbParameter = testCMD.Parameters.Add & _
("@numtitlesout", OleDbType.Integer)
NumTitles.Direction = ParameterDirection.Output
auIDIN.Value = "213-46-8915"
PubsConn.Open()
Dim myReader As OleDbDataReader = testCMD.ExecuteReader()
Console.WriteLine("Book Titles for this Author:")
Do While myReader.Read
Console.WriteLine("{0}", myReader.GetString(2))
Loop
myReader.Close()
Console.WriteLine("Return Value: " & (RetValue.Value))
Console.WriteLine("Number of Records: " & (NumTitles.Value))
Modify the connection string for the Connection object to point to the server that is running SQL Server.
Run the code. Notice that the DataReader retrieves the records and then returns the parameter values. You can use the Read method of the DataReader object to move through the returned records.
The Output window displays the titles of two books, the return value of 5, and the output parameter, which contains the number of records (2). Notice that you must close the DataReader in the code to see the parameter values. Additionally, note that you do not have to move through all of the records to see the return parameters if the DataReader is closed.
Use the ExecuteScalar Method of the Command Object
You can use the ExecuteScalar method of the Command object to retrieve parameter values. Additionally, ExecuteScalar returns the first column of the first row of the stored procedure. This is most useful for aggregate functions as in the following example.
Create the following stored procedure on the server that is running SQL Server:
Create Procedure TestProcedure2
(
@au_idIN varchar (11)
)
As
/* set nocount on */
select count (T.title)
from authors as A join titleauthor as TA on
A.au_id=TA.au_id
join titles as T
on T.title_id=TA.title_id
where A.au_id=@au_idIN
Return(5)
Use the Imports statement on the System and the System.Data namespaces so that you do not have to qualify declarations in those namespaces later in your code. You must use the Imports statement prior to any other declarations. Make sure that you copy only the code for the provider that you have chosen.SQL Client
Imports System.Data.SqlClient
OLE DB Data Provider
Imports System.Data.OleDb
Add the following code to the Form_Load event:SQL Client
Dim PubsConn As SqlConnection = New SqlConnection & _
("Data Source=server;integrated security=sspi;" & _
"initial Catalog=pubs;")
Dim testCMD As SqlCommand = New SqlCommand & _
("TestProcedure2", PubsConn)
testCMD.CommandType = CommandType.StoredProcedure
Dim RetValue As SqlParameter = testCMD.Parameters.Add & _
("RetValue", SqlDbType.Int)
RetValue.Direction = ParameterDirection.ReturnValue
Dim auIDIN As SqlParameter = testCMD.Parameters.Add & _
("@au_idIN", SqlDbType.VarChar, 11)
auIDIN.Direction = ParameterDirection.Input
auIDIN.Value = "213-46-8915"
PubsConn.Open()
Dim intCount As Integer = testCMD.ExecuteScalar
Console.WriteLine(intCount)
Console.WriteLine("Return Value: " & (RetValue.Value))
OLE DB Data Provider
Dim PubsConn As OleDbConnection = New OleDbConnection & _
("Provider=SQLOLEDB;Data Source=server;" & _
"integrated Security=sspi;initial catalog=pubs;")
Dim testCMD As OleDbCommand = New OleDbCommand & _
("TestProcedure2", PubsConn)
testCMD.CommandType = CommandType.StoredProcedure
Dim RetVal As OleDbParameter = testCMD.Parameters.Add & _
("RetVal", OleDbType.Integer)
RetVal.Direction = ParameterDirection.ReturnValue
Dim IdIn As OleDbParameter = testCMD.Parameters.Add & _
("@au_idIN", OleDbType.VarChar, 11)
IdIn.Direction = ParameterDirection.Input
IdIn.Value = "213-46-8915"
PubsConn.Open()
Dim intCount As Integer = testCMD.ExecuteScalar
Console.WriteLine("Number of Rows: " & intCount)
Console.WriteLine(RetVal.Value)
Modify the connection string for the Connection object to point to the server that is running SQL Server.
Run the code. Notice that the ExecuteScalar method of the Command object returns the parameters. ExecuteScalar also returns the value of column 1, row 1 of the returned rowset. Thus, the value of intCount is the result of the count function from the stored procedure.
Use the ExecuteNonQuery Method of the Command Object
This sample uses the ExecuteNonQuery method to run the query and to return the parameter values. ExecuteNonQuery also returns the number of records that are affected after the query runs. However, ExecuteNonQuery does not return any rows or columns from the stored procedure.
The ExecuteNonQuery method is most useful when you use INSERT, UPDATE, or DELETE statements if you only have to know how many rows are changed. In a stored procedure in which you are using only a SELECT statement, you receive -1 because no rows are affected by the query.
Create the following stored procedure on the server that is running SQL Server:
Create Procedure TestProcedure3
(
@au_idIN varchar (11),
@au_fnam varchar (30)
)
As
/* set nocount on */
Update authors set au_fname = @au_fnam
where au_id = @au_idin
return (5)
Use the Imports statement on the System and the System.Data namespaces so that you do not have to qualify declarations in those namespaces later in your code. You must use the Imports statement prior to any other declarations. Make sure that you copy only the code for the provider that you have chosen.SQL Client
Imports System.Data.SqlClient
OLE DB Data Provider
Imports System.Data.OleDb
Add the following code to the Form_Load event:SQL Client
Dim PubsConn As SqlConnection = New SqlConnection & _
("Data Source=server;integrated security=sspi;" & _
"initial Catalog=pubs;")
Dim testCMD As SqlCommand = New SqlCommand & _
("TestProcedure3", PubsConn)
testCMD.CommandType = CommandType.StoredProcedure
Dim RetValue As SqlParameter = testCMD.Parameters.Add & _
("RetValue", SqlDbType.Int)
RetValue.Direction = ParameterDirection.ReturnValue
Dim auIDIN As SqlParameter = testCMD.Parameters.Add & _
("@au_idIN", SqlDbType.VarChar, 11)
auIDIN.Direction = ParameterDirection.Input
Dim auFname As SqlParameter = testCMD.Parameters.Add & _
("@au_fnam", SqlDbType.VarChar, 30)
auFname.Direction = ParameterDirection.Input
auIDIN.Value = "213-46-8915"
auFname.Value = "Marjorie"
PubsConn.Open()
Dim rvRows As Integer = testCMD.ExecuteNonQuery
Console.WriteLine(rvRows)
Console.WriteLine(RetValue.Value)
OLE DB Data Provider
Dim PubsConn As OleDbConnection = New OleDbConnection & _
("Provider=SQLOLEDB;Data Source=server;" & _
"integrated Security=sspi;initial catalog=pubs;")
Dim testCMD As OleDbCommand = New OleDbCommand & _
("TestProcedure3", PubsConn)
testCMD.CommandType = CommandType.StoredProcedure
Dim RetVal As OleDbParameter = testCMD.Parameters.Add & _
("RetVal", OleDbType.Integer)
RetVal.Direction = ParameterDirection.ReturnValue
Dim IdIn As OleDbParameter = testCMD.Parameters.Add & _
("@au_idIN", OleDbType.VarChar, 11)
IdIn.Direction = ParameterDirection.Input
Dim FnameIn As OleDbParameter = testCMD.Parameters.Add & _
("@au_fname", OleDbType.VarChar, 30)
FnameIn.Direction = ParameterDirection.Input
IdIn.Value = "213-46-8915"
FnameIn.Value = "Marjorie"
PubsConn.Open()
Dim intRowAffected As Integer = testCMD.ExecuteNonQuery
Console.WriteLine("Number of Rows affected: " & intRowAffected)
Console.WriteLine(RetVal.Value)
Modify the connection string for the Connection object to point to the server that is running SQL Server.
Run the code. The Output window displays the number of affected rows (intRowAffect) and the value of the return parameter.
