February 2011 ~ LEARN MS-ACCESS TIPS AND TRICKS

Attachment Field in Access2007

a.p.r. pillaiFebruary 28, 2011Attachment, External Links, Field Type 1 comment

Working with images or animations in applications like Microsoft Access has always been enjoyable. I have used the Office Assistant for message boxes in all my Access applications, particularly when creating and deploying common VBA library programs across the network.

Not everyone may know that it is possible to display custom images in the Office Assistant control. I have leveraged this feature to display custom greetings to Access users on special occasions such as Christmas, Eid, and Onam simply by replacing the standard company logo image on the server. I was extremely disappointed when Microsoft removed this feature in Office 2007.

For those still using Microsoft Access 2003 or earlier, the following links provide tips and tricks for using the Office Assistant with MsgBox:

The Attachment field type in Access 2007 has significant flexibility, allowing multiple external documents or images to be stored in a single record without inflating the database size. This overcomes the limitations of the older Object Linking and Embedding (OLE) method, which was commonly used in the earlier Access versions for storing, editing, or displaying images. While a Hyperlink field can link to only one external file or a single internal object (such as a form or report), the Attachment field supports multiple items per record.

This feature is useful for storing and retrieving essential documents related to a record, such as project site plans, diagrams, contract agreements, engineering drawings, or employees’ family photos. Each attached document or image can be edited in its native application, preserving full functionality.

A Sample Demo.

Open Microsoft Access 2007.
If you have already created the Northwind 2007 sample database, open it; otherwise, select Local Templates from the Template Categories.
Click on the Northwind 2007 Template to select it.
Click on the Folder icon on the right side of the File Name control and select the required folder to save the Northwind 2007.accdb database.
Click on the Create Command Button to create the sample database and open it.
Close the Home Form.
Select Object Type from the drop-down list in the Navigation Pane and select Tables.
Right-click on the Employees table and select Design View from the Shortcut Menu.
Use the right scroll bar to move the field list up and bring the last field, Attachments, with field type Attachment, into view.
Now that we have seen the Attachment Field in the Employees Table (or you can create a new Table with the Attachment Field if you prefer), close the design view.
Open the Employees Table in Datasheet View.
Move the horizontal scroll bar and bring the attachment field into view. See the sample image shown below:

Right-click to open Large Image in New Tab/Window.
The second column (highlighted) is the attachment field where a paper clip image and a number in brackets (zero) displays how many attachments are in each record.
There are no attachments added in any of those records so far, so we will do that; double-click in the attachment field of the first record.
The Attachment control opens up. Click on the Add… Command Button to browse for files on the hard disk. You may select a Word Document, Excel File, PDF file, or Image.
Repeat this action to attach more files to the same field.
Click OK to close the dialog box. You will now see a number appearing in brackets, indicating how many attachments are in that field of the record.
Double-click on the attachment field to open and show the attached files.
Click on one of the files to select it.
If you click on the Remove Command Button, you can remove the selected attachment or click Open to open the document in its parent/preview Application.
If you right-click the attachment field, the Manage Attachment shortcut menu is displayed. Selecting this option will open up the earlier dialog box we have seen for attaching /removing/opening external files.

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PrimaryKey usage with Many Fields

a.p.r. pillaiFebruary 20, 2011Fields, Primary-Key, Process Controls No comments

Introduction.

When designing a master table in Microsoft Access, it is important to maintain the uniqueness of at least one column value to make data retrieval easier. For example, in the Employees table of the Northwind.mdb sample database, each employee is identified by a unique employee code. But who ensures the uniqueness of the values entered into the employee-code field?

While it is possible to validate user input with VBA before saving the record, database systems already provide this functionality through the use of a Primary Key index. The primary key not only prevents duplicate values but also organizes the data automatically in ascending or descending order.

Usage of Indexes in Programs.

We use these field values in programs to retrieve the specific information very fast. Let us write a small VBA Routine to see how this is used in programs.

Public Function PrimaryKey_Example1(ByVal EmpCode As Integer)
Dim db As Database, rst As Recordset

Set db = CurrentDb
Set rst = db.OpenRecordset("Employees", dbOpenTable)
rst.Index = "PrimaryKey" 'activate the Index on Employee Code

rst.Seek "=", EmpCode 'we are looking for the record of Employee Code provided
'Let us test whether the search for Employee Code was successfull or not
If Not rst.NoMatch Then
    MsgBox "EC: " & rst![ID] & " - " & rst![First Name] & " " & rst![last name]
Else
    MsgBox "EC: " & EmpCode & " Not found!"
End If

Set rst = Nothing
Set db = Nothing

End Function

The statement rst.Index = "PrimaryKey" activates the index named PrimaryKey. A primary key index can include more than one field, and a table may contain several indexes within the Indexes collection, each defined with different field combinations. If a single field is not sufficient to ensure uniqueness, additional related fields can be included in the index. You can activate the appropriate index based on how you want the data organized before continuing with the processing steps.

The field contents don't always need to be numbers only; instead, they can be any value, like FirstName or LastName fields, or both, or any combination of field types: text, date, number, etc., except the Memo field. You can give any suitable name for the Index in the Index Name column.

Right-click to open Large Image in New Tab/Window.

The Recordset's Seek() method is used for search operations on the Table. One of the Indexes should be active before the Seek() operation can be executed.

In the above example, the rst.Seek "=", the Empcode statement checks for the Employee Code passed to the Index_Example1() function. The statement looks for the exact match ("=" ) very quickly.

When the Index is defined with more than one field, then search keys must be separated with commas in the Seek() method. Let us modify the above program to provide multiple values for the Index Keys in the Seek method, assuming that FirstName and LastName fields are the members of MyIndex.

Index having more than one Field Value.

Public Function PrimaryKey_Example2(ByVal strFirstName As String, ByVal strLastName As String)
Dim db As Database, rst As Recordset

Set db = CurrentDb
Set rst = db.OpenRecordset("Employees", dbOpenTable)
rst.Index = "MyIndex" 'activate the Index

'Search for the Employee record
rst.Seek "=", strFirstName, strLastName

'Let us test whether the search for the Employee was successfull or not
If Not rst.NoMatch Then
    MsgBox "Employee: " & rst![ID] & " - " & rst![First Name] & " " & rst![last name]
Else
    MsgBox "Employee: " & strFirstName & " " & strLastName & " Not found!"
End If

Set rst = Nothing
Set db = Nothing

End Function

Percentage on Report Summary

a.p.r. pillaiFebruary 13, 2011Calculation, Report, Reports, Summary No comments

Introduction.

Earlier, we solved this problem using a Query in the blog post Percentage on Total Query. This time, let’s see how to achieve the same result on a Report. Our task is to display each detail line’s value as a percentage of the report’s summary total.

The approach is simple:

Create a Report that lists the detailed values and includes a report-level summary (such as the total).
Insert a Text Box in the Detail section.
In the Text Box’s Control Source, write an expression that divides the detail value by the Report Summary total.

This way, each record line will show its proportional contribution to the overall total directly on the Report.

Design a Sample Report to Try.

Import the Order Detail Table from Microsoft Access Sample Database: C:\Program Files\Microsoft Office\Office11\Sample\Northwind.mdb
Open a new Query in SQL View, without selecting a Table from the displayed list.

Copy and paste the following SQL String into the SQL editing window of the new Query:

SELECT [Order Details].[Order ID], Sum([Order Details].Quantity) AS TQuantity, Sum([Order Details].[Unit Price]) AS UnitPrice, Sum([Unit Price]*[Quantity]) AS TotalPrice
FROM [Order Details]
GROUP BY [Order Details].[Order ID];

Save the Query with the name OrderSummary.
Design a Report (as shown in the image given below) with the Detail Section and Report Footer summary controls using the OrderSummary as the Source.
Right-click to open Large Image in New Tab/Window.
Click on the Text Box at the Footer of the Report to select it.
Display the Property Sheet (F4 or ALT+Enter) of the Text Box.
Change the Name Property Value to GTPrice (stands for Grand Total Price).
Write the expression =Sum([TotalPrice]) in the Control Source Property.
Select the Text Box at the right end of the Detail Section and display its Property Sheet.
Write the expression =[TotalPrice]/[GTPrice] in the Control Source Property.
In the Format Property, select the Percent format from the drop-down list.
Type 2 in the Decimal Places Property.
Save and Close the Report.
Open the OrderSummary in Print Preview and check the detail line percentage value calculated on the Report Footer Grand Total Price.