我想通过 ODP.net(Oracle 数据提供者)从远程 Oracle 数据库中搜索数据,但我总是收到以下错误消息:
Oracle.DataAccess.Client.OracleException was unhandled
Message=ORA-00936: missing expression
Source=Oracle Data Provider for .NET
ErrorCode=-2147467259
DataSource=RETLMCC_ETLAPPL
Number=936
Procedure=""
StackTrace:
at Oracle.DataAccess.Client.OracleException.HandleErrorHelper(Int32 errCode, OracleConnection conn, IntPtr opsErrCtx, OpoSqlValCtx* pOpoSqlValCtx, Object src, String procedure, Boolean bCheck)
at Oracle.DataAccess.Client.OracleException.HandleError(Int32 errCode, OracleConnection conn, String procedure, IntPtr opsErrCtx, OpoSqlValCtx* pOpoSqlValCtx, Object src, Boolean bCheck)
at Oracle.DataAccess.Client.OracleCommand.ExecuteReader(Boolean requery, Boolean fillRequest, CommandBehavior behavior)
at Oracle.DataAccess.Client.OracleCommand.ExecuteReader()
at WindowsFormsApplication1.Form1.Form1_Load(Object sender, EventArgs e) in C:\Documents and Settings\zhanzhex\my documents\visual studio 2010\Projects\WindowsFormsApplication1\WindowsFormsApplication1\Form1.cs:line 52
at System.Windows.Forms.Form.OnLoad(EventArgs e)
at System.Windows.Forms.Form.OnCreateControl()
at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
at System.Windows.Forms.Control.CreateControl()
at System.Windows.Forms.Control.WmShowWindow(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at System.Windows.Forms.ContainerControl.WndProc(Message& m)
at System.Windows.Forms.Form.WmShowWindow(Message& m)
at System.Windows.Forms.Form.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.SafeNativeMethods.ShowWindow(HandleRef hWnd, Int32 nCmdShow)
at System.Windows.Forms.Control.SetVisibleCore(Boolean value)
at System.Windows.Forms.Form.SetVisibleCore(Boolean value)
at System.Windows.Forms.Control.set_Visible(Boolean value)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.Run(Form mainForm)
at WindowsFormsApplication1.Program.Main() in c:\documents and settings\zhanzhex\my documents\visual studio 2010\Projects\WindowsFormsApplication1\WindowsFormsApplication1\Program.cs:line 18
at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException:
以下是我的代码:
private void Form1_Load(object sender, EventArgs e)
{
//listBox1.Items.Add(new System.Windows.Forms.CheckBox());
System.Windows.Forms.CheckBox chb1 = new System.Windows.Forms.CheckBox();
chb1.Text = "test";
checkedListBox1.Items.Add("test1");
checkedListBox1.Items.Add("test2");
checkedListBox1.Items.Add("test3");//RETLMCC_ETLAPPL
string oradb = "Data Source=RETLMCC_ETLAPPL;User Id=ABC;Password=ABC;";
OracleConnection conn = new OracleConnection();
conn.ConnectionString = oradb;
StringBuilder sb = new StringBuilder();
sb.Append(" select table_name, column_name,data_type,data_length ");
sb.Append(" from all_tab_columns@DB_LINK where table_name = @tableName order by column_name asc");
string sqlStr = sb.ToString();
//RETLMCC_ETLAPPL_SM_3_11
OracleCommand cmd = new OracleCommand();
cmd.CommandText = sqlStr;//"select name from ovsc_country_out";
cmd.Connection = conn;
cmd.CommandType = CommandType.Text;
cmd.Connection.Open();
OracleParameter paraTableName = new OracleParameter("@tableName", OracleDbType.Varchar2);
paraTableName.Value = "COMPANYM1";
OracleParameter paraDBLink = new OracleParameter("@DB_LINK", OracleDbType.Char);
paraDBLink.Value = "@RETLMCC_ETLAPPL_SM_3_11";
cmd.Parameters.Add(paraDBLink);
cmd.Parameters.Add(paraTableName);
OracleDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
checkedListBox1.Items.Add(dr["column_name"].ToString());
}
if (conn.State == ConnectionState.Open)
{
conn.Close();
}
}
如果我搜索本地数据库而不是远程数据库,代码运行良好,但是当我在我的 SQL 字符串中使用数据库链接时,我怎么能弄清楚呢?