Subdivide a database diagram (ADP)
Note The information in this topic applies only to a Microsoft Access project (.adp).
Database diagrams can range in complexity from just one table to hundreds of tables. When you’re working with a large number of tables, you can create a "master" database diagram that contains all the tables you need, and then divide the master diagram into many smaller database diagrams or "subdiagrams."
Subdivide your database diagram when you want to isolate a group of the tables. For example, if you are designing an application with many modules, you can create one master database diagram with all the tables that your application needs. You can then subdivide the master database diagram so that each subdiagram contains only the tables pertaining to a specific module.
- In the Database window, click Database Diagrams
under Objects, click the master database diagram you want to open, and then click Design on the Database window toolbar. - Create a new database diagram.
You can use a database diagram to create, edit, or delete database tables. You can also use a database diagram to see how your tables relate to each other. When you create a new database diagram, you are presented with a blank diagram surface to work on.
- In the Database window, click Database Diagrams
under Objects, and choose the New button on the Database window toolbar.
A blank database diagram appears with the Add Table dialog box.
- To add a table to the database diagram, select a table, and then click Add.
-or-
To create a new table in the diagram, right-click anywhere inside the database diagram and then choosing New Table from the shortcut menu.
- Arrange the objects in your database diagram.
If you want to move objects to different parts of your diagram
— for example, to align the tables or reduce the number of overlapping relationship lines — first select the objects, and then drag the selection to its new location. - To select a table, click its title bar.
- To select a set of tables, hold down the CTRL key as you click inside the title bar of each table in the set.
- To select a set of tables grouped together, position the pointer near one of the tables and then drag a rectangle around all the tables in the set.
If you select multiple tables, the relationship lines that connect them are automatically included in the selection.
If you select a relationship line, you can slide a line segment to a location that is parallel to its original position. If the relationship line has more than one segment, you can drag a corner diagonally to change both its vertical and horizontal position.
- In the Database window, click Database Diagrams
- In the master database diagram, select the group of tables you want to isolate in the subdiagram.
You can perform actions on a group of objects by selecting multiple objects in a database diagram. You can select multiple objects that are adjacent to each other or that are spatially separated from each other by other objects.
Select all objects in the diagram- Right-click the diagram and choose Select All from the shortcut menu.
Select a group of adjacent tables- Hold down the SHIFT key while you click each table that you want to add to your selection.
–or–
- Point to the diagram background and drag a rectangle around the tables you want to select. Each table does not have to be fully contained in the rectangle to be selected.
Select a group of spatially separated tables- Hold down the CTRL key while you click each table that you want to add to your selection. If you click the title bar of an already selected table, that table is removed from the selection.
Select a group of adjacent columns- Hold down the SHIFT key while you click the row selector
of the first and last columns that you want to select. This method selects every column from the column that displays the selected row indicator 
to the last row selector you clicked.
Select a group of spatially separated columns- Hold down the CTRL key while you click the row selector of each column that you want to add to your selection. If you click the row selector of an already selected column , that column is removed from the selection.
- Click the relationship line.
You can select only one relationship line at a time. For example, you can select a relationship line when you want to change its properties. When you select a group of tables, the relationship lines between the tables are automatically included in the selection.
- Copy or drag the tables into the new database diagram.
Because each table that appears in a database diagram is merely a reference to a database table, you need to edit the table in only one database diagram in order for your changes to be immediately reflected in each database diagram in which the table appears.