Insert excerpt |
---|
| _Banners |
---|
| _Banners |
---|
name | ERD |
---|
nopanel | true |
---|
|
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.
The process for creating defining data structures in an ERD is slightly different depending depends on whether or not you have already created tables in PhixFlow. The 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 | Primary Key | See |
---|
I have CSV or Excel data |
These types of file can be dragged directly onto an ERD canvas and PhixFlow will automatically import 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 will be unique
- or add an attribute called UID with
- Data Type = Integer
- Precision = 10
|
Set - and set one attribute to be the Display Name.
| - Creating Tables in an ERD, below.
|
I have no data | Define the |
streamstables, 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.
|
Also see: |
I have data but it's not in PhixFlow | Use an analysis model to connect to your data |
and its the data structures to create tables. |
When you run analysis, PhixFlow loads the data records.
streamtable: - 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 - and set one attribute to be the Display Name.
| |
I have tables in PhixFlow already | In the ERD toolbar, click |
table_listtable_list to display a list of all the |
streams streams tables into the ERD and then add the relationships. |
Creating Tables in an ERD
Drag and Drop Import: Create a New Table using
CSV or Excel DataExcel or CSV
- Drag a CSV or Excel file directly onto an ERD canvas.
- PhixFlow will create creates a table automatically based on the information in the file.
This topic is also covered in the ERD Fundamentals video course found here: ; see Entity Relationship Diagrams.
Create a
New TableNew Table
- Drag
Insert excerpt |
---|
| _table_new |
---|
| _table_new |
---|
nopanel | true |
---|
|
from the toolbar into the diagram. - In the pop-uppopup, enter a name that reflects what the table will represent. For example
Customer
. - PhixFlow opens the properties tab for the new table on the right and adds the table to the canvas.
The table header displays its name. PhixFlow automatically adds 2 two attributes:
- UID, a primary key that is a unique identifier for each record.
- Name, a display name which that is shown instead of the numeric UID in a view or form will be used to provide a user-friendly name to the user in place of the numeric UID.
- To add attributes to the streamtable:
- In the streamtable, click . PhixFlow opens the attribute properties on the right, with the default settings of:
- Type = String
- Length = 50 characters.
- 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
- Click
Insert excerpt |
---|
| _finish |
---|
| _finish |
---|
nopanel | true |
---|
|
to save the attribute properties.
- PhixFlow adds the attribute to the stream 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 the desired 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.
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 |
---|
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
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 streamstables, right-click a table to show the context 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
.
To remove the related table from your ERD, in the toolbar, click
Insert excerpt |
---|
| _refresh |
---|
| _refresh |
---|
nopanel | true |
---|
|
.
Saving ERDs
Changes to an ERD Any changes you make on the ERD canvas are automatically saved.
Accessing Properties
You can set properties for all the items in an ERD. To access properties for:
- the ERD: in the canvas toolbar click
Insert excerpt |
---|
| _property_settings |
---|
| _property_settings |
---|
nopanel | true |
---|
|
- Table tables: in the ERD, click on the stream the table header or right-click to open the pop-up popup menu and select
Insert excerpt |
---|
| _config |
---|
| _config |
---|
nopanel | true |
---|
|
- Attributeattributes: in the streamtable, click on an attribute.
PhixFlow opens the properties panel pane on the right.