Overview

Use an ERD to define the structure of the data that backs your application. For an introduction to ERD concepts and why ERDs are important, see Understanding ERDs.

The process for creating configuring an ERD is slightly different depending on whether or not you have already created tables in PhixFlow.   The The following table summarises the different ways you can add data to an ERD, depending on your starting point:

Creating Tables in an ERD

Create a New Table using Excel or CSV

Data

1. Drag a CSV or Excel file directly onto an ERD canvas.
2. PhixFlow will create a table automatically based on the information in the file.

This topic is also covered in the ERD Fundamentals video course found here: Entity Relationship Diagrams.

Create a New Table

1. Drag 

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     from the toolbar into the diagram.
2. In the pop-up, enter a name that reflects what the table will represent. For example Customer.
3. PhixFlow opens the properties tab for the new table on the right and adds the table to the canvas.
   The table header displays its name. PhixFlow automatically adds 2 attributes:

1. • UID, a primary key that is a unique identifier for each record.
   • Name,  a display name which in a view or form will be used to provide a user-friendly name to the user in place of the numeric UID.
2. To add attributes to the streamtable:
   1. In the streamtable, click 

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      . 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 Attribute. 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 the table in the ERD.

Add an Existing Table

1. In the toolbar, click 

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   .
2. PhixFlow filters the repository to show the list of tables available in this application.
3. Drag the desired table from the repository onto the ERD canvas. 

Create Relationships

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

To create a relationship

1. Click-drag from one attribute name to another.
   1. One of the attributes must be a primary key.
2. PhixFlow highlights the attribute when your mouse pointer is over it. 
3. When the destination attribute is highlighted, release the click.

Relationships

See the table below for the relationships that can be created between attributes:

Relationship Restrictions

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.

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 table.
• 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 

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

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PhixFlow adds the related tables to your ERD. 

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

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

Saving ERDs

Changes to an ERD are automatically saved.

Accessing Properties

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

• ERD: in the canvas toolbar click

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

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• Attribute: in the streamtable, click on an attribute

PhixFlow opens the properties panel on the right.