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Overview

For an introduction to ERD concepts and why ERDs are important, see Understanding ERDs.

The process for defining data structures in an ERD depends on whether or not you have already created tables in PhixFlow. 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 

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Excel Excel

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

This topic is also covered in the ERD Fundamentals video course; see Entity Relationship Diagrams.

Create a

New Table 

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NewTable NewTable

1. Drag 

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

1. • UID, a primary key that is a unique identifier for each record.
   • Name,  a display name that is shown instead of the numeric UID in a view or form.
2. To add attributes to the table:
   1. In the table, 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 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 a 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.
   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 tables, 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

Any changes you make on the ERD canvas are automatically saved. 

Accessing Properties

To access properties for:

• the ERD: in the canvas toolbar click

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• tables: in the ERD, click on the table header or right-click to open the popup menu and select 

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• attributes: in the table, click on an attribute.

PhixFlow opens the properties pane on the right.