Single Entity Attribute ER Diagram Drawing

Problem

• Database course assignments often require drawing one entity with its attributes, such as Movie, Student, or Book.
• Hand-drawn diagrams can suffer from uneven ellipses, inconsistent spacing, text overflow, and insufficient margins.
• This skill targets a standard single-entity attribute ER diagram and produces a ready-to-use PNG, without modeling entity relationships.

How It Works

• When both the entity name and attribute list are provided, it draws the diagram using the supplied fields.
• When only an entity name is given, it infers 4–8 typical attributes from common business fields, such as Student with id, name, gender, age, major, class, and enrollment year.
• It prefers scripts/er_draw.py, controlled by flags like --entity, --attributes, --color, --layout, --ellipse-width, and --attr-size.
• --layout auto selects a 120°, 180°, or 360° layout based on attribute count and switches to a full circle if overlaps are detected.
• If the script is unavailable, it falls back to a Python template with dependency checks, font warnings, rendering degradation, and return-code handling.
• The visual style follows textbook conventions: a rectangle for the entity, ellipses for attributes, connector lines attached only to the rectangle edge, no primary-key marks, no title, and adequate margins.

Boundaries

• Good for single-entity attribute diagrams, style adjustments, and database coursework drafts.
• Not suitable for multi-entity relationship diagrams, document export, or modifying existing images.
• Very long attribute lists may trigger truncation warnings, so splitting them into multiple diagrams is recommended.
• It requires a runtime environment with numpy and matplotlib.