- 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.