從Visual Basic中調用Oracle函數

Question

不確定爲什麼我的代碼在從VB調用時返回一個錯誤，但PLSQL（Oracle）中的類似代碼沒有返回錯誤。

Oracle函數：

CREATE OR REPLACE FUNCTION GET_CUST_STRING_FROM_DB (pcustid NUMBER) RETURN VARCHAR2 AS 
    returnstring VARCHAR2(200); 
    vcustomer customer%rowtype; 
BEGIN 
    SELECT * INTO vcustomer 
    FROM customer 
    WHERE custid = pcustid; 

    returnstring := 'CustID: ' || vcustomer.custid || ' Name: ' || vcustomer.custname || ' Status: ' || vcustomer.status || ' SalesYTD: ' || vcustomer.sales_ytd; 
    RETURN returnstring; 
EXCEPTION 
    WHEN NO_DATA_FOUND THEN 
     RAISE_APPLICATION_ERROR(-20021,'Error: Customer ID not found'); 
    WHEN OTHERS THEN 
     RAISE_APPLICATION_ERROR(-20000,SQLERRM); 
END; 
/

Oracle調用：

set serveroutput on; 

begin 
    dbms_output.put_line(get_cust_string_from_db(1)); 
end; 

甲骨文輸出：

Anonymous Block Completed 
CustID: 1 Name: Colin Smith Status: OK SalesYTD: 0 

VB代碼：

Private Sub GetCustString() 
    Try 
     Dim connOracle As Oracle.DataAccess.Client.OracleConnection 
     Dim commOracle As New Oracle.DataAccess.Client.OracleCommand 
     Dim paramOracle As Oracle.DataAccess.Client.OracleParameter 

     connOracle = CreateConnection() 
     commOracle.Connection = connOracle 
     commOracle.CommandType = CommandType.StoredProcedure 
     commOracle.CommandText = "GET_CUST_STRING_FROM_DB" 

     paramOracle = New Oracle.DataAccess.Client.OracleParameter 
     paramOracle.ParameterName = "pcustid" 
     paramOracle.DbType = DbType.Int16 
     paramOracle.Value = tbGetCustStringCustID.Text 
     paramOracle.Direction = ParameterDirection.Input 
     commOracle.Parameters.Add(paramOracle) 

     paramOracle = New Oracle.DataAccess.Client.OracleParameter 
     paramOracle.ParameterName = "pReturnValue" 
     paramOracle.DbType = DbType.String 
     paramOracle.Direction = ParameterDirection.ReturnValue 
     commOracle.Parameters.Add(paramOracle) 

     lbOutput.Items.Add(commOracle.Parameters.Item("pcustid").Value) 
     lbOutput.Items.Add("--------------------------------------------") 
     lbOutput.Items.Add("Getting Details for CustID " & tbGetCustStringCustID.Text) 

     connOracle.Open() 
     commOracle.ExecuteNonQuery() 
     Dim vStr As String 
     vStr = commOracle.Parameters.Item("pReturnValue").Value.ToString 
     lbOutput.Items.Add(vStr) 
     connOracle.Close() 
    Catch ex As Exception 
     lbOutput.Items.Add(ex.Message) 
    End Try 
End Sub 

VB輸出：

1 
----------------------------------------- 
Getting Details for CustID 1 
ORA-20021: Error: Customer ID not found 

所以我不能確定，爲什麼這件事會發生。 我試圖捕捉參數的值，並確保它是一個實際的整數，而不是一個字符串。 CustID 1確實存在於數據庫中並被提交。

任何想法？

Answer 1

您必須指定（最大值）的返回值的大小，即

paramOracle.Size = 200 

Answer 2

除了指定需要添加的返回值參數，第一個返回值的大小部份...

Private Sub GetCustString() 
    Try 
     Dim connOracle As Oracle.DataAccess.Client.OracleConnection 
     Dim commOracle As New Oracle.DataAccess.Client.OracleCommand 
     Dim paramOracle As Oracle.DataAccess.Client.OracleParameter 

     connOracle = CreateConnection() 
     commOracle.Connection = connOracle 
     commOracle.CommandType = CommandType.StoredProcedure 
     commOracle.CommandText = "GET_CUST_STRING_FROM_DB" 

     paramOracle = New Oracle.DataAccess.Client.OracleParameter 
     paramOracle.ParameterName = "pReturnValue" 
     paramOracle.DbType = DbType.String 
     paramOracle.Size = 200 
     paramOracle.Direction = ParameterDirection.ReturnValue 
     commOracle.Parameters.Add(paramOracle) 

     paramOracle = New Oracle.DataAccess.Client.OracleParameter 
     paramOracle.ParameterName = "pcustid" 
     paramOracle.DbType = DbType.Int16 
     paramOracle.Value = tbGetCustStringCustID.Text 
     paramOracle.Direction = ParameterDirection.Input 
     commOracle.Parameters.Add(paramOracle) 

     lbOutput.Items.Add(commOracle.Parameters.Item("pcustid").Value) 
     lbOutput.Items.Add("--------------------------------------------") 
     lbOutput.Items.Add("Getting Details for CustID " & tbGetCustStringCustID.Text) 

     connOracle.Open() 
     commOracle.ExecuteNonQuery() 
     Dim vStr As String 
     vStr = commOracle.Parameters.Item("pReturnValue").Value.ToString 
     lbOutput.Items.Add(vStr) 
     connOracle.Close() 
    Catch ex As Exception 
     lbOutput.Items.Add(ex.Message) 
    End Try 
End Sub