This page is for application designers who want define the data that will back the application. It explains how to draw an ERD and setup its properties.

Overview

Use an ERD to define the structure of the data that backs your application.

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Overview

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

Understanding ERDs.

Think about the structure here Make it easier to track through. We need to be mindful "if you've got data"

Bring in an excel file creates the data structure (creates the table) but that's no the same as running analysis and then loading the data (analysis pulls in the records)

The things you need to consider when defining an ERD depend

Entity Relationship Diagrams.

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

loaded data into PhixFlow. It feels like we are jumping into the middle here a little. How to define an ERD for me feels more of a natural starting point happy to discuss.

Make sure people are clear that PhixFlow can make this is you already have something
You have got data
You've got data NOT in PhixFlow
- bring it in via a model
- OR if its in Excel you can bring it in and create the model in 1 step
You've got data in PhixFlow (via model)
If you have already loaded data (link to analysis model) (both table and records), the tables are listed in the repository. I feel there is a clash here against the statement earlier "it has not been loaded yet" as we can load a file without pulling data into PhixFlow. This then sets up the table structure for us.
1. Drag tables from the repository Data → Tables into the ERD canvas. Again we want to avoid the respository we have the show tables option on an ERD.
2. Set the primary key:
  - Either create an attribute called UID that PhixFlow will populate with unique values for each record
  - Or select an attribute to be the primary key. You will need to ensure this contains unique values.
  - If you add an excel file we have discussed presenting users with the option to select a Primary Key and Display Name. There is a flow that covers this see 4.10.
3. Add relationships
  - Should we state that users need to drag and drop to create a relationship? Dragging and dropping onto an attribute creates the relationship. Dragging and dropping onto the header bar creates the corresponding attribute and relationship.
  - Primary key and foreign key attributes must have the same data Type.
If you do not have any data for your application:
1. Create tables, attributes and relationships in the ERD.
  - New tables have an attribute called UID, which is the primary key. We also create a Name attribute that is set to Display Name
  - Make sure the data Type is correct for the data that will populate each attribute. we haven't introduced the concept of creating attributes at this point, should we discuss setting a value?
  - PhixFlow adds table items to the repository. Attributes are listed within the Table properties. Should we say this as we are trying to avoid people browsing the repository, and we have the view table button on the in context menu.
  - Relationships are not listed in the repository. To see relationship properties, in the ERD, click the relationship arrow. should we go with the positive view point and say relationship details are only available on the ERD?
2. Add records to your tables:
  - either manually e.g. create a screen to allow users to enter data.
  - or from an external source, e.g. Excel file, database etc. we need to consider what to tell people, as excel can be added directly but databases et al need an analysis model to back them. lets discuss our message. Also we say add records from an external source and have no information about that?
If you have already loaded data, the tables are listed in the repository. I feel there is a clash here against the statement earlier "it has not been loaded yet" as we can load a file without pulling data into PhixFlow. This then sets up the table structure for us.
1. Drag tables from the repository Data → Tables into the ERD canvas. Again we want to avoid the respository we have the show tables option on an ERD.
2. Set the primary key:
  - Either create an attribute called UID that PhixFlow will populate with unique values for each record
  - Or select an attribute to be the primary key. You will need to ensure this contains unique values.
  - If you add an excel file we have discussed presenting users with the option to select a Primary Key and Display Name. There is a flow that covers this see 4.10.
3. Add relationships
  - Should we state that users need to drag and drop to create a relationship? Dragging and dropping onto an attribute creates the relationship. Dragging and dropping onto the header bar creates the corresponding attribute and relationship.
  - Primary key and foreign key attributes must have the same data Type.

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How to Define an ERD

Open an Existing ERD

From the home menu, select Data and click on an ERD in the list.

In the repository, open your application and find Data → 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 Insert excerpt_erd_erdnopaneltrue icon.

Create a New ERD

From the home menu, select Data.

PhixFlow displays the list of ERDs. Select Create New from the left hand side.

In the pop-up, enter a name for your ERD, and a description then click Insert excerpt_dialog_finish_dialog_finishnopaneltrue.

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 Table

In the toolbar, click Table ListImage RemovedThe icon is called tables and the icon here is wrong as it includes the category name. Review the context menus for full details and please take the icons from the Icon repository directory on sharepoint.
PhixFlow filters the repository to show the list of tables available in this application.
Drag a table from the repository onto the ERD canvas.

Create a New Table

Drag Table Create

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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.

I have tables in PhixFlow already

In the ERD toolbar, click

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to display a list of all the tables. Drag tables into the ERD and then add the relationships.

Note

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Creating Tables in an ERD

Drag and Drop Import: Create a New Table using Excel or CSV
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Drag a CSV or Excel file directly onto an ERD canvas.
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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Drag
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from the toolbar into the diagram.
In the

pop-up

popup, enter a name

, for example "Customer" and click Insert excerpt_dialog_finish_dialog_finishnopaneltrue.PhixFlow

that reflects what the table will represent. For example, Customer.
PhixFlow opens the properties for the new table and adds the table to the canvas

and opens its properties tab on the right. Rhe

.
The table header displays

the

its name

entered in step 2

.PhixFlow automatically adds

2

two attributes:

- UID

- the unique identifier and primary key.Name - (which also gets auto added and set as the display name - concept to explain)

- , 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.
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

, Type and Length for the data; see Attributes.
PhixFlow creates attributes with a Type or String and Length of 50 characters. Remember to select

1. and select appropriate type properties

for an attributes data

1. , 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
2. Click
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dialog_

1. finish

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the

1. to save the attribute properties.
PhixFlow adds the attribute to

the table Changes to tables, attributes and relationships are automatically saved to the ERD. However, you must

the table in the ERD.

Tip

Add an Existing Table

In the toolbar, click
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save

tables
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tables
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to keep any changes you make to the layout, such as moving tables or adding corners to relationships.What is meant by "adding corners"? I don't recognise this term at all. This is to do angle points, can we make the terminology consistent here. Also if you drag a table onto an ERD does it save automatically. We need to confirm this as I would not expect it to as the same does not happen in analysis models.

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

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Create Relationships

In an ERD you can create a one-to-many relationship between a primary key in

one table

one table with an attribute in another table. For relationship concepts, see

Understanding ERDs

Entity Relationship Diagrams.

To create a relationship

, click Expand

title	More detail

Click on the source attribute.

Drag to the destination attribute.

:

Click-drag from one attribute name to another.

It's not any attribute to any attribute. We need to add a note that dragging a UID onto a header will auto create a foreign key.

One of the attributes must be a primary key.
PhixFlow highlights the attribute when your mouse pointer is over it.
When the destination attribute is highlighted, release the click.

Rearranging ERDs

To move tables around in the ERD, click on the header and drag the table. There are also Align options in the toolbar that you can use to line up or distribute selected tables.

To select multiple tables, draw a square around them.

If you want to highlight the relationships that affect a table, click the table to select it. The following screenshot shows the Teacher table is selected.

Blue lines indicate relationships to a foreign key in the selected table
Green lines indicate relationships from the primary key in the selected table.
Should we add the concept of 1:many and many:1 here?

If a table has a lot of attributes that you do not need to see you can collapse the list to show only the table's primary and foreign keys.

either right-click on a table and select Hide attributes or Show attributes
or double-click on the table header.

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By default, relationships are straight lines, but you can change them to have angles (shown in the screenshot on the left).

Click on a relationship line to add an angle point, which appears as a blue dot.
Move the mouse pointer over the blue dot. It changes to a four-way arrow to indicate you can drag.
Drag the point to the position you require.

To remove an unwanted angle, right-click the blue dot and select Remove Point (shown in the screenshot on the right).

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Properties

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Basic Settings

FieldDescriptionName

The name for the ERD.

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How PhixFlow Manages Different Relationship Drags

DragRelationship line

Foreign key type

If PhixFlow does any automatic changing of types, then record them here

From table1To table2primary keyattribute

table1.primarykey → table2.attribute
one → many

Table has no records:

Table has records: 21052021 PhixFlow creates relationships with types that don't match

attributeprimary key

table2.primarykey → table1.attribute
one → many

primary keyprimary keytable1.primarykey → table2.primarykey
one → one 21052021 should this work? Noattributeattribute

if table1 has no primary key: PhixFlow makes the table1.attribute the primary key

if table 1 has a primary key: relationship is from table1.primarykey instead of from table1.attribute.

ERD Toolbar we haven't defined this in our terminology document but we have been calling it the In Context Toolbar to ensure there is no ambiguity with any other options.

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

OptionDescription

Create

CreateDrag this icon onto the canvas to create a table.ScreenCreates a new screen for the selected table.

List

TablesClick to see a list available tables.ScreensClick to see a list available screens.

Canvas

SaveSave changes to the diagram. If there is no save icon, PhixFlow is saving changes automatically.Refresh

Redraw the ERD to display recent changes to the diagram.

PropertiesOpen the properties for the current diagram.

Zoom out

Zoom out to see more of the diagram, with smaller text.

Zoom in

Zoom in to see a smaller area of the diagram, with larger text.

Ungroup

Select a grouped set of items and then click to ungroup them.

Select several items then click to group them together.

Group

Select several items then click to group them together.

Back

For screen layout, move a component back.

ForwardFor screen layout, bring a component forward.

Align options

Click/hover to show all the options for aligning items on the canvas.

Align Grid

Organise selected items into a grid pattern.

Align left

Align selected items to the left.

Align right

Align selected items to the right.

Align top

Align selected objects to the top.

Align bottom

Align selected objects to the bottom.

Distribute horizontally

For 3 or more items, distributes the selected items evenly between the left and right items.

Distribute vertically

For 3 or more items, distributes the selected items evenly between the top and bottom items.

Table Pop-up Menu

You can access more options in a pop-up menu:

in the table header, click Insert excerpt_more_options_erd_more_options_erdnopaneltrue

right-click anywhere in the table.

OptionRename to Description

Configure Table

Table properties

Open the properties for this table.

Remove this item from the Diagram

Remove from ERD

Remove the selected item(s) from the diagram.

Hide AttributesHide attributesCollapse the table so that it only shows the table name, primary key and any foreign keys. Other attributes are hidden.Show AttributesShow attributesExpand the table to show all the attributesParmanently DeleteDelete everywhereDDelete the selected item(s) from the ERD and from everywhere it is used

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Relationships

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

Drag from		Relationship
Table 1	Table 2	Relationship
primary key	attribute	1:Many Table1.primarykey → Table2.attribute
attribute	primary key	1:Many Table2.primarykey → Table1.attribute
attribute	attribute	If Table1 has no primary key, PhixFlow makes the Table1.attribute the primary key. If Table1 has a primary key, the relationship is from Table1.primarykey instead of from the attribute being dragged.

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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Tip
If you have created several ERDs to define the data structure that your application requires, then each ERD is a view onto a part of the full data structure.

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:

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PhixFlow adds the related tables to your ERD.

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

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from 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
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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.

Version	Old Version 44	New Version Current
Changes made by	Fiona Sargeant (Unlicensed)	Zoe Baldwin
Saved on	Jun 16, 2021	Sept 17, 2024

Page Comparison

Versions Compared

Key

Overview

Overview

How to Define an ERD

Open an Existing ERD

Create a New ERD

Add an Existing Table

Create a New Table

Creating and Importing Data

Creating Tables in an ERD

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

Create a New Table AnchorNewTableNewTable

Add an Existing Table

Create Relationships

Rearranging ERDs

Properties

Basic Settings

How PhixFlow Manages Different Relationship Drags

ERD Toolbar we haven't defined this in our terminology document but we have been calling it the In Context Toolbar to ensure there is no ambiguity with any other options.

Create

List

Canvas

Table Pop-up Menu

Relationships

Relationship Restrictions

Show Relationships From Other ERDs Anchorerd-viewerd-view

Saving ERDs

Accessing Properties

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

Create a New Table
Anchor
NewTable
NewTable

Show Relationships From Other ERDs
Anchor
erd-view
erd-view