如何使用 Ref Cursor 和 return Visual Basic 上的值调用 Oracle 函数
How to call an Oracle function with a Ref Cursor and return the values on Visual Basic
我正在尝试从 VB 调用 return SYS_REFCURSOR 的 Oracle 函数。我能够使用存储过程检索数据。以同样的方式我试图调用 oracle 函数但它给出了一个错误。
如果有人能提供帮助,我将不胜感激?谢谢。如果需要,我会提供屏幕截图。
DB端函数
PKG BODY
FUNCTION GET_ALLCUST RETURN SYS_REFCURSOR AS
getallcursor SYS_REFCURSOR;
BEGIN
OPEN getallcursor FOR SELECT * FROM CUSTOMER;
RETURN getallcursor;
CLOSE getallcursor;
END;
PKG Spec
==============
create or replace PACKAGE GetAllProdPckg AS
PROCEDURE GetAllProd;
PROCEDURE get_allprod_viasqldev;
PROCEDURE get_allcust_viasqldev;
FUNCTION get_allcust RETURN SYS_REFCURSOR;
function GET_ALLPROD_FROM_DB RETURN SYS_REFCURSOR;
END GetAllProdPckg;
我的代码=========================================== ==============================
Private Sub Button1_Click_1(sender As Object, e As EventArgs) Handles Button1.Click
Dim rvConn As Oracle.DataAccess.Client.OracleConnection
rvConn = CreateConnection()
Dim rvCmd As New Oracle.DataAccess.Client.OracleCommand
' Dim OracleRefCursor As New Oracle.DataAccess.Client.OracleDbType.RefCursor
Dim ds As DataSet
Dim oraDataAdapter As New Oracle.DataAccess.Client.OracleDataAdapter()
Try
rvCmd.Connection = rvConn
rvConn.Open()
Dim strSQL As String
strSQL = "getallprodpckg.get_allcust"
rvCmd.CommandType = CommandType.StoredProcedure
rvCmd.CommandText = strSQL
MsgBox("")
Dim qrySerial3 As New Oracle.DataAccess.Client.OracleParameter("getallpcursor", OracleDbType.RefCursor) With {
.Direction = ParameterDirection.ReturnValue}
rvCmd.Parameters.Add(qrySerial3)
Dim vStr As String
Dim reader As OracleDataReader = rvCmd.ExecuteReader
While reader.Read()
Console.WriteLine("{0}", reader(0) & reader(1) & reader(2))
MsgBox(vStr)
End While
Catch ex As Exception
MessageBox.Show("ERROR OCCURRED" & ex.Message)
Finally
rvConn.Close()
End Try
End Sub
当我使用游标对象调用存储过程时,上面的代码会 return 一个值。
游标基本上 return 中的所有数据来自 table。
但是当我在一个函数上尝试它时它会抛出一个异常,我试过的代码如下。
** 错误 **
System.NullReferenceException: '对象引用未设置到对象的实例。
Exception Thrown
Private Sub Button1_Click_1(sender As Object, e As EventArgs) Handles Button1.Click
Dim rvConn As Oracle.DataAccess.Client.OracleConnection
rvConn = CreateConnection()
Dim rvCmd As New Oracle.DataAccess.Client.OracleCommand
' Dim OracleRefCursor As New Oracle.DataAccess.Client.OracleDbType.RefCursor
Dim ds As DataSet
Dim oraDataAdapter As New Oracle.DataAccess.Client.OracleDataAdapter()
Try
rvCmd.Connection = rvConn
rvConn.Open()
Dim strSQL As String
strSQL = "select getallprodpckg.get_allcust() from dual"
rvCmd.CommandType = CommandType.Text
rvCmd.CommandText = strSQL
MsgBox("")
Dim qrySerial2 As New Oracle.DataAccess.Client.OracleParameter("getallpcursor", OracleDbType.RefCursor) With {
.Direction = ParameterDirection.ReturnValue}
rvCmd.Parameters.Add(qrySerial2)
Dim vStr As String
Dim reader As OracleDataReader = rvCmd.ExecuteReader
While reader.Read()
Console.WriteLine("{0}", reader(0) & reader(1) & reader(2))
MsgBox(vStr)
End While
Catch ex As Exception
MessageBox.Show("ERROR OCCURRED" & ex.Message)
Finally
rvConn.Close()
End Try
End Sub
End Class
** 数据库连接 class **
Public Class Form1 Private Sub TestOracleButton_Click(sender As Object, e As EventArgs) Handles TestOracleButton.Click TestOracleConnection() End Sub
Dim custID As Integer
Dim custID2 As Integer
Dim custName As String
Dim prodID As Integer
Dim prodName As String
Dim prodPrice As Integer
Dim prodAmount As Integer
Dim custAmount As Integer
Dim custStatus As String
Dim prodQuant As Integer
Public Sub TestOracleConnection()
Dim rvConn As Oracle.DataAccess.Client.OracleConnection
rvConn = CreateConnection()
Try
rvConn.Open()
MessageBox.Show("Oracle Connection OK")
Catch ex As Exception
MessageBox.Show(ex.Message)
MessageBox.Show("No Oracle Connection established")
Finally
rvConn.Close()
End Try
End Sub
Public Function CreateConnection() As Oracle.DataAccess.Client.OracleConnection
Dim rvConn As New Oracle.DataAccess.Client.OracleConnection With {
.ConnectionString = GetConnectionString()
}
Return rvConn
End Function
Public Function GetConnectionString() As String
Dim vConnStr As String
vConnStr = "Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)"
vConnStr = vConnStr & "(HOST=feenix-oracle.swin.edu.au)(PORT=1521))"
vConnStr = vConnStr & "(CONNECT_DATA=(SERVICE_NAME=dms)));"
vConnStr = vConnStr & "User Id=S1234564;"
vConnStr = vConnStr & "Password=******;"
Return vConnStr
End Function
您需要从参数而不是命令中获取 reader。
所以不用
Dim reader As OracleDataReader = rvCmd.ExecuteReader()
你需要:
rvCmd.CommandType = CommandType.StoredProcedure
rvCmd.CommandText = "getallprodpckg.get_allcust"
Dim qrySerial3 As New Oracle.DataAccess.Client.OracleParameter(
None, OracleDbType.RefCursor, ParameterDirection.ReturnValue)
rvCmd.Parameters.Add(qrySerial3)
rvCmd.ExecuteNonQuery()
Dim cursor as OracleRefCursor = DirectCast(qrySerial3.Value, OracleRefCursor)
Dim reader As OracleDataReader = cursor.GetDataReader()
我正在尝试从 VB 调用 return SYS_REFCURSOR 的 Oracle 函数。我能够使用存储过程检索数据。以同样的方式我试图调用 oracle 函数但它给出了一个错误。
如果有人能提供帮助,我将不胜感激?谢谢。如果需要,我会提供屏幕截图。
DB端函数
PKG BODY
FUNCTION GET_ALLCUST RETURN SYS_REFCURSOR AS
getallcursor SYS_REFCURSOR;
BEGIN
OPEN getallcursor FOR SELECT * FROM CUSTOMER;
RETURN getallcursor;
CLOSE getallcursor;
END;
PKG Spec
==============
create or replace PACKAGE GetAllProdPckg AS
PROCEDURE GetAllProd;
PROCEDURE get_allprod_viasqldev;
PROCEDURE get_allcust_viasqldev;
FUNCTION get_allcust RETURN SYS_REFCURSOR;
function GET_ALLPROD_FROM_DB RETURN SYS_REFCURSOR;
END GetAllProdPckg;
我的代码=========================================== ==============================
Private Sub Button1_Click_1(sender As Object, e As EventArgs) Handles Button1.Click
Dim rvConn As Oracle.DataAccess.Client.OracleConnection
rvConn = CreateConnection()
Dim rvCmd As New Oracle.DataAccess.Client.OracleCommand
' Dim OracleRefCursor As New Oracle.DataAccess.Client.OracleDbType.RefCursor
Dim ds As DataSet
Dim oraDataAdapter As New Oracle.DataAccess.Client.OracleDataAdapter()
Try
rvCmd.Connection = rvConn
rvConn.Open()
Dim strSQL As String
strSQL = "getallprodpckg.get_allcust"
rvCmd.CommandType = CommandType.StoredProcedure
rvCmd.CommandText = strSQL
MsgBox("")
Dim qrySerial3 As New Oracle.DataAccess.Client.OracleParameter("getallpcursor", OracleDbType.RefCursor) With {
.Direction = ParameterDirection.ReturnValue}
rvCmd.Parameters.Add(qrySerial3)
Dim vStr As String
Dim reader As OracleDataReader = rvCmd.ExecuteReader
While reader.Read()
Console.WriteLine("{0}", reader(0) & reader(1) & reader(2))
MsgBox(vStr)
End While
Catch ex As Exception
MessageBox.Show("ERROR OCCURRED" & ex.Message)
Finally
rvConn.Close()
End Try
End Sub
当我使用游标对象调用存储过程时,上面的代码会 return 一个值。 游标基本上 return 中的所有数据来自 table。 但是当我在一个函数上尝试它时它会抛出一个异常,我试过的代码如下。 ** 错误 ** System.NullReferenceException: '对象引用未设置到对象的实例。
Exception Thrown
Private Sub Button1_Click_1(sender As Object, e As EventArgs) Handles Button1.Click
Dim rvConn As Oracle.DataAccess.Client.OracleConnection
rvConn = CreateConnection()
Dim rvCmd As New Oracle.DataAccess.Client.OracleCommand
' Dim OracleRefCursor As New Oracle.DataAccess.Client.OracleDbType.RefCursor
Dim ds As DataSet
Dim oraDataAdapter As New Oracle.DataAccess.Client.OracleDataAdapter()
Try
rvCmd.Connection = rvConn
rvConn.Open()
Dim strSQL As String
strSQL = "select getallprodpckg.get_allcust() from dual"
rvCmd.CommandType = CommandType.Text
rvCmd.CommandText = strSQL
MsgBox("")
Dim qrySerial2 As New Oracle.DataAccess.Client.OracleParameter("getallpcursor", OracleDbType.RefCursor) With {
.Direction = ParameterDirection.ReturnValue}
rvCmd.Parameters.Add(qrySerial2)
Dim vStr As String
Dim reader As OracleDataReader = rvCmd.ExecuteReader
While reader.Read()
Console.WriteLine("{0}", reader(0) & reader(1) & reader(2))
MsgBox(vStr)
End While
Catch ex As Exception
MessageBox.Show("ERROR OCCURRED" & ex.Message)
Finally
rvConn.Close()
End Try
End Sub
End Class
** 数据库连接 class **
Public Class Form1 Private Sub TestOracleButton_Click(sender As Object, e As EventArgs) Handles TestOracleButton.Click TestOracleConnection() End Sub
Dim custID As Integer
Dim custID2 As Integer
Dim custName As String
Dim prodID As Integer
Dim prodName As String
Dim prodPrice As Integer
Dim prodAmount As Integer
Dim custAmount As Integer
Dim custStatus As String
Dim prodQuant As Integer
Public Sub TestOracleConnection()
Dim rvConn As Oracle.DataAccess.Client.OracleConnection
rvConn = CreateConnection()
Try
rvConn.Open()
MessageBox.Show("Oracle Connection OK")
Catch ex As Exception
MessageBox.Show(ex.Message)
MessageBox.Show("No Oracle Connection established")
Finally
rvConn.Close()
End Try
End Sub
Public Function CreateConnection() As Oracle.DataAccess.Client.OracleConnection
Dim rvConn As New Oracle.DataAccess.Client.OracleConnection With {
.ConnectionString = GetConnectionString()
}
Return rvConn
End Function
Public Function GetConnectionString() As String
Dim vConnStr As String
vConnStr = "Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)"
vConnStr = vConnStr & "(HOST=feenix-oracle.swin.edu.au)(PORT=1521))"
vConnStr = vConnStr & "(CONNECT_DATA=(SERVICE_NAME=dms)));"
vConnStr = vConnStr & "User Id=S1234564;"
vConnStr = vConnStr & "Password=******;"
Return vConnStr
End Function
您需要从参数而不是命令中获取 reader。
所以不用
Dim reader As OracleDataReader = rvCmd.ExecuteReader()
你需要:
rvCmd.CommandType = CommandType.StoredProcedure
rvCmd.CommandText = "getallprodpckg.get_allcust"
Dim qrySerial3 As New Oracle.DataAccess.Client.OracleParameter(
None, OracleDbType.RefCursor, ParameterDirection.ReturnValue)
rvCmd.Parameters.Add(qrySerial3)
rvCmd.ExecuteNonQuery()
Dim cursor as OracleRefCursor = DirectCast(qrySerial3.Value, OracleRefCursor)
Dim reader As OracleDataReader = cursor.GetDataReader()