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

The process for creating an ERD is slightly different depending on whether or not you have already created tables streams in PhixFlow.  The following table following stream summarises the different ways you can add tables to an ERD, depending on your starting point. (See the sections below for details of how to add tables and relationships.)



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Starting PointProcessPrimary KeySee
I have no data

Define the tablesstreams, attributes and their relationships in the ERD.

Later you will need to add records to the tablesstreams:

  • either manually, for example create a screen in which application users can enter data.
  • or via an analysis model.

PhixFlow automatically creates each table each stream with:

  • a primary key called UID
  • a Name attribute
  • the Name attribute set as the display name; see Display Name.

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Creating a Screen from a Stream
Load Data

I have data but it's not in PhixFlowUse an analysis model to connect to your data. PhixFlow can read the data structures to create tablesstream. When you run analysis on the model, PhixFlow loads the data records.

In each tablestream:

  • either set one attribute as the primary key and ensure all values will be unique
  • or add an attribute called UID with 
    • Data Type = Integer
    • Precision = 10
  • Set one attribute to be the Display Name.
Load Data
I have tables streams in PhixFlow already

In the ERD toolbar, click

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

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Note

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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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     icon.

Create a New ERD

  1. In the repository,  find ERD. Right-click to display the context menu, and select 
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  2. Enter a name for your ERD, and a description then click 

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    .

    Tip

    When you are creating tablesstreams, choose a name that reflects the entity your table 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

Table

Stream

  1. In the toolbar, click 
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    .
  2. PhixFlow filters the repository to show the list of tables streams available in this application.
  3. Drag a table a stream from the repository onto the ERD canvas. 

Create a

New Table

New Stream

  1. Drag 
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      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 table stream on the right and adds the table to the canvas.
    The header displays the name entered in step 2. PhixFlow automatically adds 2 attributes:
    • UID - PhixFlow requires a unique identifier and primary key for each tablestream.
    • 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.
  1. To add attributes to the tablestream:
    1. In the tablestream, 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 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.
  2. PhixFlow adds the attribute to the table the stream in the ERD.

Create Relationships

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

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

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  1. Click on the source attribute.
  2. Drag to the destination attribute. PhixFlow highlights the attribute when your mouse pointer is over it. 
  3. When the destination attribute is highlighted, release the click.

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

DragRelationship line
From table1stream1To table2stream2
primary keyattribute

table1stream1.primarykey → table2stream2.attribute
1:many

attributeprimary key

table2stream2.primarykey → table1stream1.attribute
1:many

attributeattribute

if table1 stream1 has no primary key: PhixFlow makes the table1stream1.attribute the primary key

if table if stream 1 has a primary key: the relationship is from table1stream1.primarykey instead of from table1stream1.attribute.

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 tablethe 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.

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. 

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

  • Show many to one relations Todo Todo-Fiona - check icons 
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  • Show one to many relations Todo-Fiona - check icons 
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PhixFlow adds the related tables streams to your ERD. 

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

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.

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

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.

Saving ERDs

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

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 in the toolbar. PhixFlow notifies you if there are unsaved changes when you attempt to close an ERD.

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

Rearranging ERDs

To move tables streams 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.

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

  • Blue lines indicate relationships to a foreign key in the selected tableselected stream
  • Green lines indicate relationships from the primary key in the selected tablestream.

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

  • Either right-click on a table stream and select Hide attributes or Show attributes
  • Or double-click on the table stream header.


To select multiple tablesstreams, draw a square around them. 

By default, relationships are straight lines, but you can change them to have angles.

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

To remove an unwanted angle, right-click the blue dot and select Remove Point; see the screenshot on the right.

Properties

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Basic Settings

FieldDescription
Name

The name for the ERD.

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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.

OptionDescription

Create options

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Drag this icon onto the canvas to create a tablestream.

List options

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Click to open the repository filtered to list the tables streams available in your application.

 Canvas options

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Open the help topic with details about working with ERDs.
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Options to arrange the selected tables streams in the ERD:

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_align_top
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nopaneltrue

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nopaneltrue

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_distribute_horizontal
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Open the properties tab for the ERD.
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Zoom out to see more of the diagram, with smaller text.
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Zoom in to see a smaller area of the diagram, with larger text.
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_save
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PhixFlow automatically saves changes to tables streams and relationships.
Use this icon to save diagram layout changes to the ERD.

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Update the ERD to the last saved diagram layout. This clears any unsaved layout changes. 
Your ERD should automatically show an changes elsewhere in PhixFlow.  For example, if someone adds a new attribute to a table a stream in your ERD, the attribute will appear on the list. If changes are not appearing, click this icon.

Ungroup

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

Select several items then click to group them together.

Table

Stream Pop-up Menu

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

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OptionDescription

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Open the properties for this tablestream.

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Remove the selected item(s) from the diagram.

Show many to one relations
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Tables Streams may have relationships to other tables streams not represented on the current ERD. Use these options to add all related tables 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

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Toggle the table the stream between expanded to show all attributes or collapsed to show only the table stream name, primary key and any foreign keys. This is useful if your table stream contains many attributes.

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Delete the selected item(s) from the ERD and from everywhere it is used.

Attribute Pop-up Menu

OptionDescription
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Set the current attribute to be a primary key. Remember to unset any other primary key in the tablestream
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_key_foriegn_set
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Set the current attribute to be a foreign key.

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_attributes
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Create a new attribute for the tablestream. PhixFlow opens the properties where you can add a name and set the data type.
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 attribute
Delete the attribute from the tablestream. PhixFlow prompts you to confirm.


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Things not yet implemented
For the Starting Point
table
 stream:
I have data in Excel files

Drag the Excel files directly into an ERD. PhixFlow loads the data structure and records. It then adds the table stream to the ERD.

In the ERD, you then add the relationships between tablesstreams.

PhixFlow prompts you to set the primary key and display name attributes.Link to doc on XD flow 4.10
For Open an Existing ERD
  1. From the home menu, select Data and click on an ERD in the list.
  2. In the repository, open your application and find Data → ERD.
    • Either right-click on an ERD name and select Display.
    • Or...
For Create a New ERD
  1. From the home menu, select Data.
  2. PhixFlow displays the list of ERDs. Select Create New from the left hand side.
  3. In the pop-up, enter a name for your ERD, and a description then click 

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    .

    Tip

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


  4. 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.

For Create a
Table
Stream From an Excel File  Document Flow 4.10
For Create Relationships
table
Stream
primary keytable stream headertable1stream1.primarykey → table2stream2.new-attribute
1:many