用oledb访问数据库提示符号不匹配怎么解决
1。在ORACLE中建立了如下的表:
CREATE TABLE CPOINT.Users
(UserId number(4) Primary Key,
UserName Varchar2(40),
UserType Number(1),
Pwd Varchar2(40) NOT NULL,
EmpName Varchar2(40)
);
INSERT INTO CPOINT.Users Values(1, 'Admin', 1, 'Admin', 'Admin');
INSERT INTO CPOINT.Users Values(2, 'Admin', 2, 'Admin', 'Admin');
INSERT INTO CPOINT.Users Values(3, 'Admin', 3, 'Admin', 'Admin');
2。在vs。net中用如下方法访问数据库
public static void test()
{
string ConnectString= "Provider=MSDAORA;User ID=cpoint;Data
Source=CPOINT22;Password=cpoint";
OleDbConnection myConnection = new OleDbConnection(ConnectString);
myConnection.Open();
string select="select userid from Users" ;
OleDbCommand cmd = new OleDbCommand(select,myConnection);
OleDbDataReader _reader = cmd.ExecuteReader();
while ( _reader.Read())
{
System.Console.WriteLine(_reader.GetInt32(0).ToString());
}
myConnection.Close();
}
3。提示的错误信息如下:
System.InvalidCastException:由于符号不匹配或数据以外的其他原因,未能转换数据
值。例如,数据在数据存储区中已经损坏,但改行仍可检索。
at System.Data.OleDb.DBBindings.get_ValueInt32()
at System.Data.OleDb.OleDbDataReader.GetInt32(Int32 ordinal)
4.请问如何解决哦?!
谢谢!