PRB: Cannot Set Default Value for Access (Jet) Text Fields

ID: Q180611

The information in this article applies to:

The DAO SDK, included with:
- Microsoft Visual C++, 32-bit Editions, versions 5.0, 6.0
- The Microsoft Foundation Classes (MFC)
- Microsoft Access versions 7.0, 97

SUMMARY

MORE INFORMATION

Steps to Reproduce Behavior

The following code reproduces the problem. The code below assumes that you have an Access database called "db1.mdb" in the root of the C drive:

Sample Code


   void setFI( CDaoFieldInfo &fi)
   {
      fi.m_strName = _T("testfield");
      fi.m_nType = dbText;
      fi.m_lSize = 50;
      fi.m_lAttributes = dbFixedField;
      fi.m_nOrdinalPosition = 2;
      fi.m_bRequired = FALSE;
      fi.m_bAllowZeroLength = TRUE;
      fi.m_lCollatingOrder = dbSortGeneral ;
      // fi.m_strDefaultValue = _T("\"11North\""); // Corrects the error.
      fi.m_strDefaultValue = _T("11North"); // Displays the error.
   }

   void CMy1aDlg::OnBUTcreateTbl()
   {
      CDaoDatabase db;
      try
      {
         db.Open(_T("c:\\db1.mdb"));
         CDaoTableDef td(&db);
         td.Create(_T("FieldTest"));
         CDaoFieldInfo fi;
         setFI( fi);
         td.CreateField(fi);
         td.Append();

         CDaoRecordset rs(&db);
         rs.Open(dbOpenDynaset, _T("Select * from FieldTest"));
         rs.AddNew();
         rs.Update();
         rs.Close();
         db.Close();
      }
   catch(CDaoException *de)
      {
         CString strMsg;
         strMsg.Format(
         _T("ERROR:CDaoException\n\n")
         _T("SCODE_CODE      =%d\n")
         _T("SCODE_FACILITY   =%d\n")
         _T("SCODE_SEVERITY   =%d\n")
         _T("ResultFromScode   =%d\n"),
         SCODE_CODE      (de->m_scode),
         SCODE_FACILITY   (de->m_scode),
         SCODE_SEVERITY   (de->m_scode),
         ResultFromScode (de->m_scode));
         AfxMessageBox(strMsg);
         de->Delete();
      }
   }

To reproduce this problem in Access, open up a table in Design View. In the Default Value Edit field, enter 1abc (without quotation marks) and then click on another field.

SYMPTOMS

If you try to set the default value for a text field with a string that starts with a number (for example, 11North), you will get an error. If you set the DAO Struct CDaoFieldInfo fi field member as:


   fi.m_strDefaultValue = _T("11North");

and then call CDaoTableDef::CreateField(fi), DAO throws an exception reporting:

Syntax error (missing operator) in table-level validation expression. (3320)

If you open the Access table in Design View, click the General Tab, and try to enter 11North in the Default Value field, Access displays an error dialog box with the message:

The Expression you have entered contains invalid syntax.
You may have entered an operand without an operator.

CAUSE

The error occurs because Access accepts expressions for the default value. (Expressions are operators, constants, functions, literal values, and so on.) When the default value begins with a number, Access tries to store the default as a number.

RESOLUTION

You must use double quotes so that Access knows the default value is a string. For example, to do this programmatically, the code is:


   fi.m_strDefaultValue = _T("\"11North\"");

If you are working directly with an Access table in Design View, you must start the string with a quote. For example, "11North".

Additional query words: kbvc500 kbvc600 kbmfc

Keywords : kbDAO
Version :
Platform : Win95 winnt
Issue type : kbprb