How to Define an ERD

Open an Existing ERD

In the repository, find ERD.

• Either right-click on an ERD name and select Display.
• Or double-click the ERD name to open the properties. In the properties toolbar, click the

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  _erd_display _erd_display nopanel true

   icon.

Create a New ERD

1. In the repository,  find ERD. Right-click to display the context menu, and select 

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   _add _add nopanel true

2. Enter a name for your ERD, and a description then click 

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   _finish _finish nopanel true

   .

   Tip
   When you are creating streams, choose a name that reflects the entity your stream represents.

   
   

3. PhixFlow opens a new ERD canvas on the left with a toolbar at the top. Hover your mouse pointer over toolbar icons to display a tooltip.

Add an Existing Stream

1. In the toolbar, click 

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   _table_list _table_list nopanel true

   .
2. PhixFlow filters the repository to show the list of streams available in this application.
3. Drag a stream from the repository onto the ERD canvas. 

Create a New Stream

1. Drag 

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   _table_new _table_new nopanel true

     from the toolbar into the diagram.
2. In the pop-up, enter a name, for example "Customer", and click

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   .
3. PhixFlow opens the properties tab for the new stream on the right and adds the table stream to the canvas.
   The header displays the name entered in step 2. PhixFlow automatically adds 2 attributes:

1. • UID - PhixFlow requires a unique identifier and primary key for each stream.
   • Name -  PhixFlow sets the Name attribute to be the display name. In data grids and forms etc. PhixFlow uses this attribute to provide a user-friendly name, rather than a numeric identifier. Optionally, change the attribute name.
2. To add attributes to the stream:
   1. In the stream, click 

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      _new _new nopanel true

      . PhixFlow opens the attribute properties on the right, with the default settings of:
      • Type = String
      • Length = 50 characters.
   2. In the properties, enter the Name and select appropriate type properties, such as Date or Integer; see Attributes. The following data types have additional properties:
      • For String add Length
      • For Integer add Precision
      • For Decimal add Significant Figures and Decimal Places
   3. Click 

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       to save the attribute properties.
3. PhixFlow adds the attribute to the stream in the ERD.

Create Relationships

In an ERD you can create a one-to-many relationship between a primary key in one stream with an attribute in another stream. For relationship concepts, see Understanding ERDs and Views.

To create a relationship, click-drag from one attribute to another.

See the stream below for the relationships that can be created between attributes.

PhixFlow cannot create a relationship between your selected attributes if your selected foreign key attribute: 

• is already a foreign key to a different primary key.
• has a different Data Type and type properties to the primary key.

In these cases, PhixFlow reports an error: Related attributes must have the same type and length. This type/length is different.

If this happens, you can:

• create a new attribute to be the foreign key
• change the foreign key attributes to match the primary key, provided there is no data in the stream
• create the relationship with a different attribute.

To change the data type properties, In the ERD, click on an attribute to open its properties.

Show Relationships From Other ERDs 

Anchor
erd-view erd-view

If a stream appears on more than one ERD it may have relationships with streams that are not visible in your current ERD. To see other related streams, right-click a table stream to show the context menu and select:

• Show many to one relations Todo Todo-Fiona - check icons 

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  _rel_in _rel_in nopanel true

• Show one to many relations Todo-Fiona - check icons 

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  _rel_out _rel_out nopanel true

PhixFlow adds the related streams to your ERD. 

To keep the related streams in your ERD, in the toolbar, click 

To remove the related streams from your ERD, in the toolbar, click 

Saving ERDs

Changes to streams, attributes and relationships are automatically saved. However, to keep any changes you make to the layout of a diagram, such as moving tables streams or adding angle points to relationships, remember to click 

Accessing Properties

You can set properties for all the items in an ERD. To access properties:

• for the ERD: in the canvas toolbar click

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  _property_settings _property_settings nopanel true

• for a stream: in the ERD, click on the stream header or right-click to open the pop-up menu and select 

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• for an attribute: in the stream, click on an attribute
• for a relationship: in the ERD, click on the relationship line. For relationships you can only add or change the description.

PhixFlow opens the properties panel on the right.

Properties

Basic Settings

Toolbars and Popup Menus

ERD Toolbar

The toolbar is at the top of the canvas. Hover your mouse pointer over the toolbar to see a tooltip.

Stream Pop-up Menu

To access more options in a pop-up menu, in the stream header, click 

Option	Description
Insert excerpt _config _config nopanel true todo-Fiona - check Can this be  Insert excerpt _property_settings _property_settings nopanel true	Open the properties for this stream.
Insert excerpt _remove _remove nopanel true	Remove the selected item(s) from the diagram.
Show many to one relations todo-Fiona - should be  Insert excerpt _rel_out _rel_out nopanel true	Streams may have relationships to other streams not represented on the current ERD. Use these options to add all related streams to your ERD so that you can see the full relationship set; see Show Relationships From Other ERDs , above.
Show one to many relations todo-Fiona - should be  Insert excerpt _rel_in _rel_in nopanel true
Insert excerpt _attributes_show_hide _attributes_show_hide nopanel true	Toggle the stream between expanded to show all attributes or collapsed to show only the stream name, primary key and any foreign keys. This is useful if your stream contains many attributes.
Insert excerpt _delete _delete nopanel true	Delete the selected item(s) from the ERD and from everywhere it is used.

Attribute Pop-up Menu