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.Insert excerpt | ||||||||
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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
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Creating and Importing Data
Starting Point | Process | Primary Key | See |
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I have CSV or Excel data | Drag the file onto the ERD canvas. PhixFlow automatically imports the data for you. | In each table:
|
|
I have no data | Define the |
tables, attributes and their relationships in the ERD. Later you will need to add records to the |
table:
| PhixFlow automatically creates |
each table with:
|
|
|
Load
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:
|
|
I have |
tables in PhixFlow already | In the ERD toolbar, click
|
|
|
tables. Drag |
tables into the ERD and then add the relationships. |
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Creating Tables in an ERD
Open an Existing ERD
In the repository, find ERD.
Create a New ERD
In the repository, find ERD. Right-click to display the context menu, and selectTip |
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When you are creating streams, choose a name that reflects the entity your stream represents. |
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 Stream
In the toolbar, clickDrag 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
from the toolbar into the diagram.Insert excerpt _table_new _table_new nopanel true - In the
- popup, enter a name
- 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.
The table header displays
- its name
- .PhixFlow automatically adds
- two attributes:
- 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.
- To add attributes to the
- table:
- In the
- table, click
. PhixFlow opens the attribute properties on the right, with the default settings of:Insert excerpt _new _new nopanel true - Type = String
- Length = 50 characters.
- In the properties, enter the Name and select appropriate type properties, such as Date or Integer; see
- table, click
- Attribute. The following data types have additional properties:
- For String add Length
- For Integer add Precision
- For Decimal add Significant Figures and Decimal Places
- Click
to save the attribute properties.Insert excerpt _finish _finish nopanel true
- Attribute. The following data types have additional properties:
- PhixFlow adds the attribute to
- the table in the ERD.
Add an Existing Table
- In the toolbar, click
.Insert excerpt _table_list _table_list nopanel true - 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 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
- Click-drag from one attribute name to another.
title | More detail |
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- 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.
Relationships
See the
table below for the relationships that can be created between attributes
:
Drag from | Relationship |
---|
Table 1 | Table 2 | |
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primary key | attribute | 1:Many |
Table1.primarykey → |
Table2.attribute |
1:many
attribute | primary key |
1:Many Table2.primarykey → |
Table1.attribute |
1:many
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.
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 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 Anchor erd-view erd-view
erd-view | |
erd-view |
Tip |
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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:
Insert excerpt _rel_in _rel_in nopanel true
Insert excerpt _rel_out _rel_out nopanel true
PhixFlow adds the related
tables to your ERD.
To keep the related
tables in your ERD, in the toolbar, click
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To remove the related
table from your ERD, in the toolbar, click
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Saving ERDs
Any changes you make
Accessing Properties
You can set properties for all the items in an ERD. To access properties:
foron the ERD canvas are automatically saved.
Accessing Properties
To access properties for:
- the ERD: in the canvas toolbar click
Insert excerpt _property_settings _property_settings nopanel true
- tables: in the ERD, click on
- the table header or right-click to open the
- popup menu and select
Insert excerpt _config _config nopanel true
PhixFlow opens the properties panel on the right.
Rearranging ERDs
To move 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 stream, click the stream to select it. The following screenshot shows the Teacher stream is selected.
- Blue lines indicate relationships to a foreign key in the selected stream
- Green lines indicate relationships from the primary key in the selected stream.
If a stream has a lot of attributes that you do not need to see, collapse the list to show only the stream's primary and foreign keys.
- Either right-click on a stream and select Hide attributes or Show attributes
- Or double-click on the stream header.
To select multiple streams, draw a square around them.
Properties
Basic Settings
The name for the ERD.
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.
Create options
List options
Canvas options
Options to arrange the selected streams in the ERD:
Use this icon to save diagram layout changes to the ERD.
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 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.
Stream Pop-up Menu
To access more options in a pop-up menu, in the stream header, clicktodo-Fiona - check Can this be
Open the properties for this stream.
Remove the selected item(s) from the diagram.
Show one to many relations
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Toggle the stream between expanded to show all attributes or collapsed to show only the stream name, primary key and any foreign keys. This is useful if your stream contains many attributes.
Attribute Pop-up Menu
hidden | true |
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Things not yet implemented
For the Starting Point stream:
Drag the Excel files directly into an ERD. PhixFlow loads the data structure and records. It then adds the stream to the ERD.
In the ERD, you then add the relationships between streams.
For 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...
For Create a New ERD
Tip |
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When you are creating streams, choose a name that reflects the entity your stream represents. |
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 Stream From an Excel File Document Flow 4.10
For Create Relationships Stream
1:many
- attributes: in the table, click on an attribute.
PhixFlow opens the properties pane on the right.