List Relationships not represented correctly

[otyrrell]

List Relationships not represented correctly

[jayqi]

Hi @otyrrell,

Strange! I did not have an issue with your example.

(Note that your code is not quite fully reproducible. You're missing a BaseModel import and a List import.)

Can you provide the output of erd.create(A).to_dot()?

As well, can you provide the version of Pydantic, Pygraphviz, and Graphviz that you are using?

---

EDIT: I am noticing though that my version is missing the O so something is still a little wacky here...

[otyrrell]

Sorry, I didn't copy the full code, please see full segment below:

import erdantic as erd
from erdantic.examples.pydantic import Party
from typing import List
from pydantic import BaseModel

# Easy one-liner
erd.draw(Party, out="diagram.png")


class B(BaseModel):
    """
    B Class
    """

    id: str


class A(BaseModel):
    """
    A Class
    """

    list_b: List[B]


erd.draw(A, out="A.jpg")
result = erd.create(A).to_dot()
print(result)

This provides the output:

digraph "Entity Relationship Diagram" {
        graph [fontcolor=gray66,
                fontsize=9,
                label="Created by erdantic v0.6.0 <https://github.com/drivendataorg/erdantic>",
                nodesep=0.5,
                rankdir=LR,
                ranksep=1.5
        ];
        node [fontsize=14,
                label="\N",
                shape=plain
        ];
        "__main__.A"    [label=<<table border="0" cellborder="1" cellspacing="0"><tr><td port="_root" colspan="2"><b>A</b></td></tr><tr><td>list_b</td><td port="list_b">List[B]</td></tr></table>>,
                tooltip="__main__.A&#xA;&#xA;A Class&#xA;"];
        "__main__.B"    [label=<<table border="0" cellborder="1" cellspacing="0"><tr><td port="_root" colspan="2"><b>B</b></td></tr><tr><td>id</td><td port="id">str</td></tr></table>>,
                tooltip="__main__.B&#xA;&#xA;B Class&#xA;"];
        "__main__.A":list_b:e -> "__main__.B":_root:w   [arrowhead=crowodot];
}

Name: erdantic
Version: 0.6.0
Name: pydantic
Version: 2.3.0
Name: pygraphviz
Version: 1.11
GraphViz version 9.0.0 on Windows 10 x64

Only other thing I found is that it seems very specific to crow notation; when I changed "crow" to "icurve" on line 55 in erd.py it all works as expected (although showing the curve notation not the required crows foot)

[jayqi]

The DOT output looks like what I expect, and copy-pasting it into this online renderer seems to produce the expected image. https://dreampuf.github.io/GraphvizOnline

So that suggests something funky is happening at the pygraphviz/graphviz level. Will find some time to dig into this more.

[otyrrell]

Thank you for clarifying. I agree it does appear to be some sort of bug/unexpected behaviour within pygraphviz/graphviz. I couldn't find any relevant reports of crow foot notation having issues. I guess next step is understanding whether it is in the graphviz or the pygraphviz layer?

[jayqi]

I'm not seeing this anymore with pygraphviz 1.12, graphviz 9.0.0. Closing as resolved unless there are additional details provided.