Adding Content to an ERD

Overview

For an introduction to ERD concepts and why ERDs are important, see Entity Relationship Diagrams.

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 and Importing Data

Starting Point	Process	Attributes	Further Topics
I have CSV or Excel data	Drag the file onto the ERD canvas. PhixFlow automatically imports the data for you.	In each table: either set one attribute as the Primary Key and ensure all values are unique or add an attribute called UID with  Data Type = Integer Precision = 10 and set one attribute to be the Display Name.	Creating Tables in an ERD, below.
I have no data	Define the tables, attributes and their relationships in the ERD. Later you will need to add records to the table: either manually, for example, create a screen in which application users can enter data. or via an Analysis Model.	PhixFlow automatically creates each table with: a Primary Key called UID a Name attribute, as the Display Name.	Creating Tables in an ERD, below. Creating a Screen from an ERD Table 2. Importing Data
I have data but it's not in PhixFlow	Use an Analysis Model to connect to your data. PhixFlow can read the data structures to create tables.	In each table: either set one attribute as the Primary Key and ensure all values are unique or add an attribute called UID with  Data Type = Integer Precision = 10 Tick Primary Key and set one attribute to be the Display Name.	Importing Data Analysis Models for Batch Processing Data
I have tables in PhixFlow already	In the ERD toolbar, click  Table to display a list of all the tables. Drag tables into the ERD and then add the relationships.

Creating Tables in an ERD

Drag and Drop Import: Create a New Table using Excel or CSV

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 

1. Drag  Table 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  Create New. 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  Apply and Close 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  Table.
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 Entity Relationship Diagrams.

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 

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 popup menu and select:

•  Show many-to-one relations
•  Show one-to-many relations

PhixFlow adds the related tables to your ERD. 

To remove the related tables from your ERD, right click on each one and click  Removefrom the diagram.

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

PhixFlow opens the properties pane on the right.