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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:
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:
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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:
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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:
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I have tables in PhixFlow already | In the ERD toolbar, click
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Creating Tables in an ERD
Create a New Table using Excel or CSV Data
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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 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
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.
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
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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 on 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 attributes: in the table, click on an attribute.
PhixFlow opens the properties pane on the right.