ACC2000: How to Check Whether an Object Exists in a Database

This article shows you how to create a sample user-defined function to check whether an object exists in the current database. This can be useful before you create a new object (such as a table, a form, or a report) in the database.

Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements.

How to Create the Function

Check for the existence of an object in the current database by using the ObjectType argument to determine the type of object to be retrieved (tables, queries, forms, reports, macros, and modules) and the ObjectName argument to represent the name of the specified object type.

The function will return: CAUTION: If you follow the steps in this example, you modify the sample database Northwind.mdb. You may want to back up the Northwind.mdb file and follow these steps on a copy of the database.

To create the function follow these steps:

1. Open the sample database Northwind.mdb.
2. On the Insert menu, click Module.
3. Type the following code into the new module:

   
   Function DoesObjectExist (ObjectType$, ObjectName$)
   On Error Resume Next
   
   Dim Found_Object, Find_Object As String, ObjectNum As Integer
   Dim DB As Database, T As TableDef
   Dim Q As QueryDef, C  As Container
   Dim Msg As String
   Found_Object = -1
   Set DB = dbengine(0)(0)
   
   Select Case ObjectType$
   Case "Tables"
   
       Find_Object = DB.TableDefs(ObjectName$).Name
   
   Case "Queries"
   
       Find_Object = DB.QueryDefs(ObjectName$).Name
   
   Case Else
   
       If ObjectType$ = "Forms" Then
           ObjectNum = 1
       ElseIf ObjectType$ = "Modules" Then
           ObjectNum = 2
       ElseIf ObjectType$ = "Reports" Then
           ObjectNum = 4
       ElseIf ObjectType$ = "Macros" Then
           ObjectNum = 5
       Else
            Msg = "Object Name """ & ObjectType & """ is an invalid"
            Msg = Msg & " argument to function ObjectExists_20!"
            MsgBox Msg, 16, "ObjectExists_20"
            Exit Function
   
       End If
   
       Set C = DB.Containers(ObjectNum)
       Find_Object = C.Documents(ObjectName$).Name
   
   End Select
   
   If Err = 3265 Or Find_Object = "" Then
   
       Found_Object = 0
   
   End If
   
   DoesObjectExist = Found_Object
   
   End Function
   					

How to Use the Function

1. Open the module containing the function in Design view, and on the View menu, click Immediate Window.
2. Type the following line in the Immediate window, and then press ENTER:

   ?DoesObjectExist("Tables","Employees")
   					

If a table named "Employees" exists in the current database, - 1 is returned. If no table named Employees exists, 0 is returned.