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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 an ERD is slightly different depending 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:

Starting PointProcessPrimary KeySeeI have CSV or Excel dataThese types of file can be dragged directly onto an ERD canvas and PhixFlow will automatically import 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 one attribute to be the Display Name.
Adding CSV and Excel Data belowI have no data

Define the streams, 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 a Table below

Also see:

  1. Creating a Screen from an ERD Table
  2. Importing Data
I have data but it's not in PhixFlow

Use an analysis model to connect to your data and read its data structures to create tables.

When you run analysis, PhixFlow loads the data records.

In each stream:

  • 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.

Importing Data

Analysis Models for Batch Processing Data

I have tables in PhixFlow alreadyIn the ERD toolbar, click Insert excerpt_table_list_table_listnopaneltrue to display a list of all the streams. Drag streams into the ERD and then add the relationships. Note Insert excerpt_uid_uidnopaneltrue

Creating Tables in an ERD

Create a Table using CSV or Excel Data

  1. Drag a CSV or Excel file directly onto an ERD canvas.
  2. PhixFlow will create a table automatically based on the information in the file.

This is covered in the ERD Fundamentals video course found here: Entity Relationship Diagrams.

Create a New Table

Drag  Insert excerpt_table_new_table_newnopaneltrue  from the toolbar into the diagram.
  • In the pop-up, 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 attributes:
    • UID, a primary key that is a unique identifier for each record.
    • Name,  a display name which 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 stream:In the stream, click  Insert excerpt_new_newnopaneltrue. 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_finishnopaneltrue to save the attribute properties.
  • PhixFlow adds the attribute to the stream in the ERD.

    • Add an Existing Table

    In the toolbar, click  Insert excerpt_table_list_table_listnopaneltrue.
  • PhixFlow filters the repository to show the list of tables available in this application.
  • Drag the desired 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

    1. Click-drag from one attribute to another.
      1. 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.

    Relationships

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

    Drag fromRelationshipTable 1Table 2primary 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  Anchorerd-viewerd-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 streams, right-click a table to show the context menu and select:

    Insert excerpt_rel_in_rel_innopaneltrue Insert excerpt_rel_out_rel_outnopaneltrue

    PhixFlow adds the related tables to your ERD. 

    To keep the related tables in your ERD, in the toolbar, click  Insert excerpt_save_savenopaneltrue.To remove the related table from your ERD, in the toolbar, click  Insert excerpt_refresh_refreshnopaneltrue.

    Saving ERDs

    Changes to an ERD are automatically saved.

    Accessing Properties

    You can set properties for all the items in an ERD. To access properties:

    ERD: in the canvas toolbar click Insert excerpt_property_settings_property_settingsnopaneltrueTable : in the ERD, click on the stream header or right-click to open the pop-up menu and select  Insert excerpt_config_confignopaneltrue
  • Attribute: in the stream, click on an attribute

    • PhixFlow opens the properties panel on the right.

    Rearranging ERDs

    To move streams

    Rearranging ERDs

    Tables

    To move tables around in the ERD, click on the header and drag the streamtable. There are also Align options in the toolbar that you can use to line up or distribute selected streamstables.

    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.

    Image Removed

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

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

    To select multiple streamstables, draw a square around them. Image Removed

    Image Added

    Relationships

    If you want to highlight the relationships that affect a table, click the table to select it.

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

    The following screenshot shows the Teacher table is selected:

    Image Added

    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.screenshots below:

    Hover your mouse pointer over
    an angle to see the blue angle point.

    Right-click the blue angle point to see the Remove option