Using the ERD tool v8

New feature

The ERD tool is available in PEM 8.1.0 and later.

The Entity-Relationship Diagram (ERD) tool is a database design tool that provides a graphical representation of database tables, columns, and inter-relationships. ERD can give sufficient information for the database administrator to follow when developing and maintaining the database. To access the ERD tool, select Tools > ERD Tool. The ERD tool allows you to:

  • Design and visualize the database tables and their relationships.
  • Add notes to the diagram.
  • Align the tables and links for a cleaner look.
  • Save the diagram and open it later to continue working on it.
  • Generate ready-to-run SQL from the database design.
  • Generate the database diagram for an existing database.

ERD Tool

You can open multiple copies of the ERD tool in individual tabs simultaneously. To close a copy of the ERD tool, select the X in the upper-right corner of the tab bar.

Toolbar

The ERD Tool toolbar uses context-sensitive icons that provide shortcuts to frequently performed tasks.

File options

IconBehaviorShortcut
Open FileLoad a saved diagram.Ctrl + O
SaveSave changes to a saved diagram or save the diagram to a file.Ctrl + S
Save asOpen a new dialog box and specify a new location to save the diagram.Ctrl + Shift + S

Export options

IconBehaviorShortcut
Generate SQLGenerate the DDL SQL for the diagram and open a Query tool with the generated SQL ready for execution.Option + Ctrl + S
Download imageSave the ERD diagram in an image format.Option + Ctrl + I

Editing options

IconBehaviorShortcut
Add tableAdd a new table to the diagram. In the table dialog box, enter the table details.Option/Alt + Ctrl + A
Edit tableEdit a selected table on the diagram. In the table dialog box, enter the table details.Option/Alt + Ctrl + E
Clone tableClone the complete table structure, name it with a auto-generated name, and put it in the diagram.Option/Alt + Ctrl + C
Drop table/linkDrop a selected table or link.Option/Alt + Ctrl + D

Table relationship options

IconBehaviorShortcut
1MOpen a one-to-many relationship dialog box to add a relationship between two tables. The selected table is the referencing table and has the many endpoint of the link.Option/Alt + Ctrl + O
MMOpen a many-to-many relationship dialog box to add a relationship between two tables. This option creates a linked table from the selected columns of the two relating tables.Option/Alt + Ctrl + M

Utility Options

IconBehaviorShortcut
Add/Edit noteMake notes on table nodes while designing the database.Option/Alt + Ctrl + N
Auto alignAlign all tables and links for a cleaner look.Option/Alt + Ctrl + L
Show detailsToggle the column details. You can also choose to show few or more column details.Option/Alt + Shift + D

Zoom options

IconBehaviorShortcut
Zoom to fitZoom in/out automatically and fit all the tables to the view.Option/Alt + Shift + F
Zoom inZoom in on the diagram.Option/Alt + Shift + "+"
Zoom outZoom out on the diagram.Option/Alt + Shift + "-"

Table dialog

The table dialog box allows you to:

  • Change the table structure details.
  • Edit an existing table or add a new one.
  • See Table dialog for information on different fields.

Table node

The table node shows table details in a graphical representation:

  • On the top bar:
    • To show column details, select Details toggle.
    • When you add a note, Note becomes enabled. Select Note to changes notes.
  • The first row displays the table's schema name, like public in the example.
  • The second row displays the table's name, like users in the example.
  • The remaining rows dispalys the table's column names and their data types.
    • A column that is a primary key displays as a lock key, like id integer in the example.
    • Other columns diplay as a green column, like email character varying in the example.
  • Select the node to drag it on the canvas.
  • To open the table dialog box and change the table details, either double-click the table node or select Edit on the toolbar. See Table dialog for information on different fields.

ERD Tool - One-to-Many Dialog Box

The one-to-many link dialog box allows you to:

  • Add a foregin key relationship between two tables.
  • Select a Local Table that references another table. The Local Table has the many end point.
  • Select a Local Column that references another column.
  • Select the Referenced Table. The Referenced Table has the one end point.
  • Select the Referenced Column.

The many-to-many link dialog box allows you to:

  • Add a many-to-many relationship between two tables.
  • Create a relation table with linked columns that are derived from the two tables.
  • Select the Left Table, which is the first table that is linked. The Left Table has the one endpoint of the link with the new relation table.
  • Select the Left table Column, which is the first table's column. The Left table Column is a primary key.
  • Select the Right Table, which is the second table that is linked. The Right Table has the one endpoint of the link with the new relation table.
  • Select the Right table Column, which is the second table's column. The Right table Column is a primary key.

ERD Tool - Table Link

The table link shows the relationship between tables:

  • The single-line endpoint of the link shows the column that is the reference.
  • The three-line endpoint of the link shows the column that references.
  • If one of the columns that is a reference or that references is removed from the table, then the link drops.
  • Select the link to drag it on the canvas.

Table notes

To add a note to a table:

  1. On the toolbar, select Add/Edit note.
  2. In the window, enter your note.

When a note is added to a table, Note becomes enabled on the Table node. To check or update notes, select Note.