DBerd is a Go library and command-line tool that helps you extract database schemas and generate diagrams. It provides a flexible and extensible way to work with different database sources and output formats.
- Extract database schemas from various sources
- Format schemas into different representations
- Generate diagrams using multiple diagramming tools
- Use as a library in your Go applications or as a standalone CLI tool
- Extensible architecture for adding new sources and targets
go get github.com/holydocs/dberd# Using Go
go install github.com/holydocs/dberd/cmd/dberd@latestdocker pull ghcr.io/holydocs/dberd:latestCurrently, DBerd supports the following database sources:
- PostgreSQL: Extract schema from PostgreSQL databases using the
postgressource type; - MySQL: Extract schema from MySQL databases using the
mysqlsource type; - CockroachDB: Extract schema from CockroachDB databases using the
cockroachsource type; - ClickHouse: Extract schema from ClickHouse databases using the
clickhousesource type; - MongoDB: Extract collections from MongoDB databases using the
mongodbsource type.
DBerd supports multiple output formats and diagramming tools:
- D2: Generate/render diagrams using the D2 diagramming language
- PlantUML: Generate diagrams using PlantUML
- Mermaid: Generate diagrams using Mermaid JS
- JSON: Output schema in JSON format
Here's a simple example of how to use DBerd as a library to extract a schema from CockroachDB and generate a D2 diagram:
package main
import (
"context"
"log"
"os"
"github.com/holydocs/dberd/source/cockroach"
"github.com/holydocs/dberd/target/d2"
)
func main() {
cockroachSource, err := cockroach.NewSource("postgres://user@host:port/db?sslmode=disable")
if err != nil {
log.Fatalf("creating new cockroach source: %v", err)
}
defer cockroachSource.Close()
ctx := context.Background()
schema, err := cockroachSource.ExtractSchema(ctx)
if err != nil {
log.Fatalf("extracting cockroach schema: %v", err)
}
d2Target, err := d2.NewTarget()
if err != nil {
log.Fatalf("creating d2 target: %v", err)
}
formattedSchema, err := d2Target.FormatSchema(ctx, schema)
if err != nil {
log.Fatalf("formatting cockroach schema into d2: %v", err)
}
diagram, err := d2Target.RenderSchema(ctx, formattedSchema)
if err != nil {
log.Fatalf("rendering cockroach schema into d2: %v", err)
}
err = os.WriteFile("out.svg", diagram, 0600)
if err != nil {
log.Fatalf("writing file: %v", err)
}
}DBerd can be used as a command-line tool to extract and visualize database schemas:
# Extract schema and generate D2 diagram
dberd --source cockroach \
--target d2 \
--format-to-file schema.d2 \
--render-to-file schema.svg \
--source-dsn "postgres://user@host:port/db?sslmode=disable"Or using Docker:
docker run --rm -v $(pwd):/work ghcr.io/holydocs/dberd:latest \
--source cockroach \
--target d2 \
--format-to-file /work/schema.d2 \
--render-to-file /work/schema.svg \
--source-dsn "postgres://user@host:port/db?sslmode=disable"For example, if a Cockroach database has a schema like:
CREATE TABLE users (
id INT PRIMARY KEY,
name VARCHAR(255) NOT NULL,
email VARCHAR(255) NOT NULL,
created_at TIMESTAMP DEFAULT current_timestamp()
);
CREATE TABLE roles (
id INT PRIMARY KEY,
name VARCHAR(50) NOT NULL,
description STRING,
created_at TIMESTAMP DEFAULT current_timestamp()
);
CREATE TABLE user_roles (
user_id INT NOT NULL,
role_id INT NOT NULL,
assigned_at TIMESTAMP DEFAULT current_timestamp(),
PRIMARY KEY (user_id, role_id),
FOREIGN KEY (user_id) REFERENCES users(id),
FOREIGN KEY (role_id) REFERENCES roles(id)
);
CREATE TABLE posts (
id INT PRIMARY KEY,
user_id INT NOT NULL,
title VARCHAR(255) NOT NULL,
content STRING,
created_at TIMESTAMP DEFAULT current_timestamp(),
FOREIGN KEY (user_id) REFERENCES users(id)
);
CREATE TABLE categories (
id INT PRIMARY KEY,
name VARCHAR(100) NOT NULL,
description STRING,
parent_id INT,
created_at TIMESTAMP DEFAULT current_timestamp(),
FOREIGN KEY (parent_id) REFERENCES categories(id)
);
CREATE TABLE post_categories (
post_id INT NOT NULL,
category_id INT NOT NULL,
PRIMARY KEY (post_id, category_id),
FOREIGN KEY (post_id) REFERENCES posts(id),
FOREIGN KEY (category_id) REFERENCES categories(id)
);
CREATE TABLE comments (
id INT PRIMARY KEY,
post_id INT NOT NULL,
user_id INT NOT NULL,
content STRING NOT NULL,
created_at TIMESTAMP DEFAULT current_timestamp(),
FOREIGN KEY (post_id) REFERENCES posts(id),
FOREIGN KEY (user_id) REFERENCES users(id)
);
COMMENT ON COLUMN users.email IS 'User email address';
COMMENT ON COLUMN roles.description IS 'Role description and permissions';
COMMENT ON COLUMN categories.parent_id IS 'Self-referencing foreign key for category hierarchy';
The resulting schema.d2 will be:
direction: right
# Tables
public.users: {
shape: "sql_table"
id: "INT8 NOT NULL" { constraint: [primary_key] }
name: "VARCHAR(255) NOT NULL"
email: "VARCHAR(255) NOT NULL"
created_at: "TIMESTAMP DEFAULT current_timestamp()"
}
public.roles: {
shape: "sql_table"
id: "INT8 NOT NULL" { constraint: [primary_key] }
name: "VARCHAR(50) NOT NULL"
description: "STRING"
created_at: "TIMESTAMP DEFAULT current_timestamp()"
}
public.user_roles: {
shape: "sql_table"
user_id: "INT8 NOT NULL" { constraint: [primary_key] }
role_id: "INT8 NOT NULL" { constraint: [primary_key] }
assigned_at: "TIMESTAMP DEFAULT current_timestamp()"
}
public.posts: {
shape: "sql_table"
id: "INT8 NOT NULL" { constraint: [primary_key] }
user_id: "INT8 NOT NULL"
title: "VARCHAR(255) NOT NULL"
content: "STRING"
created_at: "TIMESTAMP DEFAULT current_timestamp()"
}
public.categories: {
shape: "sql_table"
id: "INT8 NOT NULL" { constraint: [primary_key] }
name: "VARCHAR(100) NOT NULL"
description: "STRING"
parent_id: "INT8"
created_at: "TIMESTAMP DEFAULT current_timestamp()"
}
public.post_categories: {
shape: "sql_table"
post_id: "INT8 NOT NULL" { constraint: [primary_key] }
category_id: "INT8 NOT NULL" { constraint: [primary_key] }
}
public.comments: {
shape: "sql_table"
id: "INT8 NOT NULL" { constraint: [primary_key] }
post_id: "INT8 NOT NULL"
user_id: "INT8 NOT NULL"
content: "STRING NOT NULL"
created_at: "TIMESTAMP DEFAULT current_timestamp()"
}
# References
public.categories.parent_id -> public.categories.id
public.comments.post_id -> public.posts.id
public.comments.user_id -> public.users.id
public.post_categories.category_id -> public.categories.id
public.post_categories.post_id -> public.posts.id
public.posts.user_id -> public.users.id
public.user_roles.role_id -> public.roles.id
public.user_roles.user_id -> public.users.id
And the resulting schema.svg will be:
