Bug #60088 incorrect lower bounds in relationship notation

• Submitted: 10 Feb 2011 13:29
• Modified: 26 Apr 2018 15:03
• Reporter: Jan Hidders
• Status: Not a Bug
• Category: MySQL Workbench: Modeling
• Severity: S3 (Non-critical)
• Version: 5.2.31 revision 7115
• OS: MacOS (Leopard)
• CPU Architecture: Any
• Tags: foreign-keys, notation, relationships

[10 Feb 2011 13:29] Jan Hidders

Description:
The lower bound of a relationship that is defined by a foreign is indicated incorrectly for the "from" side. If there is an FK from Table1.column1 to Table2.column2 then there is no lower bound on the number of rows in Table1 that is associated with each row in Table2, but this is (in all notations that represent it) indicated as 1.

How to repeat:
Create a foreign key from Table1.col1 to Table2.col2. Inspect the EER diagram.

In Crow's foot notation you will see  -|<  on the side of Table1, which should be -O<. 

In Classic notation and UML you will see 1..* which should be 0..*.

[10 Feb 2011 16:44] MySQL Verification Team

Which version are you using? 5.2.31a?.

[10 Feb 2011 22:59] Jan Hidders

The version I'm using: 5.2.31 revision 7115, on MacOS.

-- Jan Hidders

[10 Feb 2011 23:27] Jan Hidders

Indicating the version number. Apologies for forgetting that.

[11 Feb 2011 4:28] Valeriy Kravchuk

Thank you for the bug report.

[26 Apr 2018 15:03] Marcin Szalowicz

This is correct. In Crow's Foot Notation the -O< is used when the
relationship is optional.
The -|< is used when the relationship is mandatory.
In Workbench, when you create an FKey, the relationship is by default set to
mandatory, that's why you see the -|<.
You can of course change this by:
 - double click relation ship
 - switch to foreign key tab
Then you'll see two columns, Referenced Table and Referencing Table. Each one
will have a checkbox at the bottom with the field "mandatory".