我使用ADO.Net来调用Oracle数据库中的存储过程.存储过程的out参数是NVARCHAR2.这是存储过程:
CREATE OR replace PROCEDURE VALIDATE_Bin ( machine_dump_name IN NVARCHAR2,lpn IN NVARCHAR2,result OUT NUMBER,message OUT NVARCHAR2) IS BEGIN IF lpn LIKE 'A%' THEN result := 1; message := NULL; ELSE IF lpn IS NULL THEN result := 0; message := 'Failed Read'; ELSE result := 0; message := 'Invalid Barcode'; END IF; END IF; END;
这里是填写命令参数的c#代码:
command.Parameters.Add(new OracleParameter("machine_dumper_name",OracleType.NVarChar){Value = "My Dumper"}); command.Parameters.Add(new OracleParameter("lpn",OracleType.NVarChar) { Value ="XYZ1234"}); var resultParam = new OracleParameter("result",OracleType.Number) { Direction = ParameterDirection.Output}; command.Parameters.Add(resultParam); var messageParam = new OracleParameter("message",OracleType.NVarChar) { Direction = ParameterDirection.Output}; command.Parameters.Add(messageParam); command.ExecuteNonQuery();
如果我像这样执行它,我得到例外:
System.Exception: Parameter ‘message’: No size set for variable length data type: String.
我不担心. Oracle期望“message”参数的字符串长度.所以我在“message”参数上添加了一个size参数:
var messageParam = new OracleParameter("message",OracleType.NVarChar,255) { Direction = ParameterDirection.Output};
然后当我运行它时,我得到这个System.Data.OracleClient.OracleException:
PLS-00306: wrong number or types of arguments in call to ‘VALIDATE_Bin’