Editing ER diagrams
When you created an ER diagram manually, you must specify the tables and column joins that you want to include in the entity relationship.
When you include tables that have possible column connections in your ER diagram, you make the process of building queries and reports much easier for your users.
About this task
To edit an ER diagram:
- Double-click the ER diagram that you want to edit.
The ER Diagram editor opens. The associated data source is displayed in the left pane of the editor.
- Expand the Tables node of the Database folder.
- Drag each of the tables that you want to include in the
diagram to the right pane of the editor. A visual representation of each table that you add is displayed.
- To set up join conditions between tables, select a column
from one table and drag it to a column in another table.
A connecting line is drawn between the joined columns. You can set up multiple join conditions.
- To edit a join condition, right-click a connection line and select Edit. The Join Tables window opens.
- Select the type of join for linking two tables. The available
join types are:
- Inner join includes only those rows with matching values in both tables in the query results.
- Left outer join includes all the rows from the left table and only the rows from the right table that match with rows from the left table in the query results.
- Right outer join includes all the rows from the right table and only the rows from the left table that match with rows from the right table in the query results.
- Full outer join includes s all rows from both tables in the query result.
- Click Change. The new join conditions are saved.
- To delete a join condition, right-click a connection line
and select Delete. Note: All the join modifications (adding, editing, and deleting) that you specify for two tables in an ER diagram are automatically applied to these tables in other ER diagrams in this data source. If you add only one of the joined tables to an ER diagram, you can add the other table automatically by right-clicking the ER diagram and selecting Add Linked Tables.
- To add a textual note to the ER diagram, right-click in
the ER diagram editor and select Add Text.
A text box is displayed. You can add text, resize the text box, and move the text box from one point in the diagram to another. Use text notes allow to convey additional information about the tables and joins in the ER diagram to your users.
- To delete a text box, right-click it and select Delete.
- To show or hide a column of a table, right-click the column
name in the table diagram and select Hide/Show columns.
The Hide/Show Columns window opens and contains all of the available table columns.
- Select a column's associated check box to show the
column, clear it to hide the column, and click OK.
The Hide/Show Columns window closes and the changes to the table diagram are displayed.
- When you are finished adding tables and configuring join
conditions, click the Save icon.
The edited ER diagram is saved to the ER Diagrams folder of the data source. Now, when a user builds a query that includes one or more of these tables, the join conditions that you configured are automatically added to the query and displayed in the Query Builder editor.