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This page is for data modellers or application designers. It explains how to draw a relationship diagram and its properties.

Links to topic pages, esp concepts

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Drawing Relationship Diagrams

Create a Relationship Diagram

In the repository for your application, right-click on  Insert excerpt_relationship_diagram_relationship_diagramnopaneltrue.Click  Insert excerpt_add_addnopaneltrue.
  • In the pop-up, enter its name.
  • PhixFlow opens a properties tab on the right, and a new relationship diagram on the left. The relationship diagram has a toolbar at the top; see the Toolbar section below for details.
    • TipWhen you make any changes to the diagram, remember to  Insert excerpt_save_savenopaneltrue.

    Open a Relationship Diagram

    To open an existing relationship diagram:

  • either, in the repository, right-click on its name and select Display.
    • or, in the properties toolbar, click the . Insert excerpt_relationship_diagram_relationship_diagramnopaneltrue icon.

    Create a New Stream

    Drag the  Insert excerpt_streams_add_streams_addnopaneltrue icon from the toolbar into the diagram.In the pop-up, enter its name, for example "Customer" and click Insert excerpt_dialog_finish_dialog_finishnopaneltrue. PhixFlow opens a new Stream properties tab.
  • PhixFlow adds a box to represent the data stream, and opens the properties tab for it.
    • To add attributes to the streameither, in the properties tab on the right, In the Attributes section, click  Insert excerpt_add_addnopaneltrue.
  • or right-click the stream and select Add New Stream Attribute.
  • PhixFlow opens a Stream Attributes properties tab where you can specify details for the attribute, such as its name, data type and length. 
  • If this is the unique identifier, tick Primary Key. Remember to include ID or UID in the name.

    • Add an Existing Stream

    1. In the repository, open the list of streams.
    2. Drag a stream from the repository into the diagram. PhixFlow adds the stream with a list of all of its attributes.
    3. If the stream has many attributes, click Image Removed to collapse the stream so that it only shows the primary and foreign keys.

    Connect Attributes

    To connect attributes in different streams, click-drag from one attribute to another. PhixFlow shows the currently selected destination in bold. Release the click to connect to the selected destination.

    PhixFlow can only connect primary and foreign keys. This creates a one to many relationship. If you connect standard attributes, PhixFlow automatically sets them to be foreign keys.

    Tip

    PhixFlow automatically ticks the Primary Key or a Foreign Key boxes in the the Stream Attributes properties.

    Properties

    Insert excerpt_standard_settings_standard_settingsnopaneltrue

    Basic Settings

    FieldDescriptionNameEnter the name for the entity-relationship diagram. When yo press Return or save a new properties tab, PhixFlow opens an empty diagram in the workspace on the left

    Insert excerpt
    _Banners
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    nameERD
    nopaneltrue

    Overview

    For an introduction to ERD concepts and why ERDs are important, see Entity Relationship Diagrams.

    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 PointProcessAttributesFurther Topics
    I have CSV or Excel dataDrag 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.
    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 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 alreadyIn the ERD toolbar, click
    Insert excerpt
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     to display a list of all the tables. Drag tables into the ERD and then add the relationships.


    Note

    Insert excerpt
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    Creating Tables in an ERD

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

    1. Drag a CSV or Excel file directly onto an ERD canvas.
    2. 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 
    Anchor
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    NewTable

    1. Drag 
      Insert excerpt
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       from the toolbar into the diagram.
    2. In the popup, enter a name that reflects what the table will represent. For example, Customer.
    3. 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.
    2. To add attributes to the table:
      1. In the table, click 
        Insert excerpt
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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 Attribute. 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 
        Insert excerpt
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         to save the attribute properties.
    3. PhixFlow adds the attribute to the table in the ERD.

    Add an Existing Table

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

    Image Added

    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 Entity Relationship Diagrams.

    To create a relationship:

    1. Click-drag from one attribute name to another.
      One of the attributes must be a primary key.
    2. PhixFlow highlights the attribute when your mouse pointer is over it. 
    3. When the destination attribute is highlighted, release the click.

    Image Added

    Relationships

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

    Drag fromRelationship
    Table 1Table 2
    primary keyattribute

    1:Many

    Table1.primarykey → Table2.attribute

    attributeprimary key

    1:Many

    Table2.primarykey → Table1.attribute


    attributeattribute

    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 
    Anchor
    erd-view
    erd-view

    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:

    • Insert excerpt
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    • Insert excerpt
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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 

    Insert excerpt
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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
      Insert excerpt
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    • tables: in the ERD, click on the table header or right-click to open the popup menu and select 
      Insert excerpt
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    • attributes: in the table, click on an attribute

    PhixFlow opens the properties pane on the right.