ACC2000: Sample Code to Check for Table or Query in a Database (210398)

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The following example demonstrates how to use the sample user-defined function IsTableQuery() to determine whether a table or query exists in a database:

1. Open the sample database Northwind.mdb.
2. Create a module and type the following line in the Declarations section if it isn't already there:

   Option Explicit
   					

3. Type the following procedure:

   '********************************************************
   ' FUNCTION: IsTableQuery()
   '
   ' PURPOSE: Determine if a table or query exists.
   '
   ' ARGUMENTS:
   '   DbName: The name of the database. If the database name
   '           is "" the current database is used.
   '    TName: The name of a table or query.
   '
   ' RETURNS: True (it exists) or False (it does not exist).
   '
   '********************************************************
   
   Function IsTableQuery(DbName As String, TName As String) As Integer
   
      Dim Db As DAO.Database, Found As Integer, Test As String
      Const NAME_NOT_IN_COLLECTION = 3265
   
      ' Assume the table or query does not exist.
      Found = False
   
      ' Trap for any errors.
      On Error Resume Next
   
      ' If the database name is empty...
      If Trim$(DbName) = "" Then
         ' ...then set Db to the current Db.
         Set Db = CurrentDb()
      Else
         ' Otherwise, set Db to the specified open database.
         Set Db = DBEngine.Workspaces(0).OpenDatabase(DbName)
   
         ' See if an error occurred.
         If Err Then
            MsgBox "Could not find database to open: " & DbName
            IsTableQuery = False
            Exit Function
         End If
      End If
   
      ' See if the name is in the Tables collection.
      Test = Db.TableDefs(TName).Name
      If Err <> NAME_NOT_IN_COLLECTION Then Found = True
   
      ' Reset the error variable.
      Err = 0
   
      ' See if the name is in the Queries collection.
      Test = Db.QueryDefs(TName$).Name
      If Err <> NAME_NOT_IN_COLLECTION Then Found = True
   
      Db.Close
   
      IsTableQuery = Found
   
   End Function
   					

4. To test this function, type the following line in the Immediate window, and then press ENTER:

   ?IsTableQuery("","Invoices")
   						

   
   Note that a "-1" is displayed, indicating that the Invoices query was found (Microsoft Access stores a "-1" for True and a "0" for False).
5. Try using other valid database names and other table and query names in the line above.