Bound and unbound pictures and objects
A bound object is a picture or object that is stored in a table. When you move to a new record, the object that is displayed in the form or report changes. For example, you might want to store a picture for each employee in your company.
On the other hand, an unbound object is stored in the design of the form, report, or data access page. When you move to a new record, the object doesn't change. For example, you might want to add a logo that you created with Microsoft Paint to a form or report.
On a data access page, you can bind a picture by entering the path to that picture in a field, and then binding an image control to the field. Unlike a bound picture on a form or report, a bound picture in a data access page can't be stored in a table
Embedded and linked pictures and objects
In a form or report, a picture or object can be an embedded object or a linked object. Both bound and unbound objects can be either embedded or linked. In a form, you use a bound object frame to display an embedded or linked bound object, and you use an unbound object frame to display an embedded or linked unbound object.
When you embed an object in a form or report, Microsoft Access stores the object in your database file
When you link to an object, you can look at the object and make changes to it from your form or report, but the changes are stored in the original object file, not in your database file. You can also modify the object file separately, in which case the latest changes will appear the next time you open the form or report.
Linking to an object is useful for very large files that you don't want to include in your database file, and for files that you want to use in several forms or reports. If a linked object file is moved, you have to reconnect the link.
You can specify whether the latest changes appear in a linked object automatically, or only when you request them. If you are using an unbound object frame, those changes appear when you open the frame; if you are using a bound object frame, those changes appear when the control gets the focus.
On a data access page, you can't embed or link objects, because you can't use unbound object frames or bound object frames
Examples of bound or unbound and embedded or linked objects
| Example object |
Type of control to use |
Embedded or linked? |
|---|---|---|
| A logo on an invoice report that you don't need to update | Image control | Embedded (if disk space isn't an issue; otherwise linked) |
| A picture on a form or report that you expect to update | Unbound object frame | Embedded |
| Part of a Microsoft Excel worksheet in a sales report | Unbound object frame | Linked |
| A picture for each employee to be stored in an Employees table | Bound object frame | Embedded |
| Employee résumés (created and stored in a Word document) available from an Employees form | Bound object frame | Linked, and displayed as an icon |
Further considerations when adding pictures
An unbound picture on a form, report, or data access page can appear as a watermark, a background picture that covers the entire window. An unbound picture can also appear in a control.
If you want to add an unbound picture that appears in a control on a form or report, you use an image control or an unbound object frame. Whether you use an image control or an unbound object frame depends on whether you want to be able to edit the picture directly from the form or report. If you won't need to update the picture, you can add the picture by using an image control. Use an unbound object frame if you will need to update the picture. For most unbound pictures, you'll probably want to use an image control, because image controls load much faster than unbound object frames.
When you use a bound control to display a picture, you see a different picture for each record. The best way to display a different picture for each record is to store the paths to the pictures in a Text field. You can also store pictures in an OLE Object field in a Microsoft Access database, or in an image column in a SQL Server database to which an Access project is connected.
Security Note Users of your database or data access page will be able to view the image paths. Make sure that the paths do not include personal information, such as your name or the name of your computer.
If you want to display a different picture for each record in a data access page, you must store the locations of the pictures in a Text field
You can use only an image control to add a picture to a data access page. After you add a picture to a data access page, you won't be able to edit it. When you insert a picture in a data access page, the picture is added to the supporting files that accompany the data access page; the picture is not stored in the data access page. If you want to move a data access page to a new location, do not copy the data access page. Instead, save the data access page to the new location; the picture is automatically saved with it.
If you want a data access page to use a picture in a location that you specify instead of a picture that has been added to supporting files, you can link the picture. Linking a picture is a good idea if you are going to use a picture in more than one data access page.
Bitmaps and metafiles, and other graphics files that you can use to display a picture
You can use bitmap files (.bmp or .dib extensions), metafiles (.wmf or .emf extensions), or other graphic files such as GIF and JPEG to display background pictures or pictures in bound object frames, unbound object frames, or image controls.
When to use bitmaps
- If scaling and disk space aren't concerns, or if you don't have access to a tool that creates metafiles, use a bitmap.
- If you want to create a tiled background picture, a bitmap will work well because it won't be scaled.
- If you want to be able to make small changes to the picture, use a bitmap. With bitmaps you have pixel-level control, so that you can make very small adjustments to the picture.
When to use metafiles
- If you need to be able to adjust the size of your picture, it's better to use a metafile. Metafiles scale better than bitmaps.
- Metafiles are usually much smaller than bitmaps, so if you need to conserve disk space, use a metafile.
Many graphics programs allow you to save files as metafiles. See the documentation that came with your graphics program for details. Note that if you paste a bitmap into a graphics program and save it as a metafile, it will still be a bitmap
When to use GIF and JPEG files