Using the ERD tool v8

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.

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

Export options

Editing options

Table relationship options

Utility Options

Zoom options

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.

One-to-many link 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.

Many-to-many link dialog box

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.

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.

• On this page
• Toolbar
• File options
• Export options
• Editing options
• Table relationship options
• Utility Options
• Zoom options
• Table dialog
• Table node
• One-to-many link dialog box
• Many-to-many link dialog box
• Table link
• Table notes