Quickstart

from pathlib import Path

import sqlalchemy as sa

from sqlmermaid import get_mermaid, to_file


metadata_obj = sa.MetaData()

user = sa.Table(
    "user",
    metadata_obj,
    sa.Column("user_id", sa.Integer, primary_key=True),
    sa.Column("user_name", sa.String(16), nullable=False),
    sa.Column("email_address", sa.String(60)),
    sa.Column("nickname", sa.String(50), nullable=False),
)

departments = sa.Table(
    "departments",
    metadata_obj,
    sa.Column("department_id", sa.Integer, primary_key=True),
    sa.Column("department_name", sa.String(60), nullable=False),
)

employees = sa.Table(
    "employees",
    metadata_obj,
    sa.Column("employee_id", sa.Integer, primary_key=True),
    sa.Column("employee_name", sa.String(60), nullable=False),
    sa.Column("employee_dept", sa.Integer, sa.ForeignKey("departments.department_id")),
)

user_complaints = sa.Table(
    "complaints",
    metadata_obj,
    sa.Column("about_dept", sa.Integer, sa.ForeignKey("departments.department_id")),
    sa.Column("by_user", sa.Integer, sa.ForeignKey("user.user_id")),
    sa.Column("at_time", sa.DateTime),
    sa.Column("text", sa.String(500)),
    sa.Index("comp_ind", "text"),
)

db_file = Path("db.sqlite")
constr = f"sqlite:///{db_file}"
engine = sa.create_engine(constr)
metadata_obj.create_all(engine)

# generates the raw mermaid string
mermaid_str = get_mermaid(constr)

to_file(constr, "erd.md")

db_file.unlink()
Path("erd.md").unlink()