relspecgo/pkg/writers/drawdb

DrawDB Writer

Generates DrawDB-compatible JSON files from database schema information.

Overview

The DrawDB Writer converts RelSpec's internal database model representation into JSON format compatible with DrawDB, a free online database design tool.

Features

• Generates DrawDB JSON format
• Creates table and field definitions
• Defines relationships
• Includes visual layout information
• Preserves constraints and indexes

Usage

Basic Example

package main

import (
    "git.warky.dev/wdevs/relspecgo/pkg/models"
    "git.warky.dev/wdevs/relspecgo/pkg/writers"
    "git.warky.dev/wdevs/relspecgo/pkg/writers/drawdb"
)

func main() {
    options := &writers.WriterOptions{
        OutputPath: "diagram.json",
    }

    writer := drawdb.NewWriter(options)
    err := writer.WriteDatabase(db)
    if err != nil {
        panic(err)
    }
}

CLI Examples

# Generate DrawDB diagram from PostgreSQL database
relspec --input pgsql \
  --conn "postgres://localhost/mydb" \
  --output drawdb \
  --out-file diagram.json

# Convert GORM models to DrawDB for visualization
relspec --input gorm --in-file models.go --output drawdb --out-file design.json

# Convert JSON schema to DrawDB
relspec --input json --in-file schema.json --output drawdb --out-file diagram.json

Generated JSON Example

{
  "version": "1.0",
  "database": "PostgreSQL",
  "tables": [
    {
      "id": "1",
      "name": "users",
      "x": 100,
      "y": 100,
      "fields": [
        {
          "id": "1",
          "name": "id",
          "type": "BIGINT",
          "primary": true,
          "autoIncrement": true,
          "notNull": true
        },
        {
          "id": "2",
          "name": "username",
          "type": "VARCHAR",
          "size": 50,
          "notNull": true,
          "unique": true
        },
        {
          "id": "3",
          "name": "email",
          "type": "VARCHAR",
          "size": 100,
          "notNull": true
        }
      ],
      "indexes": [
        {
          "name": "idx_users_email",
          "fields": ["email"]
        }
      ]
    },
    {
      "id": "2",
      "name": "posts",
      "x": 400,
      "y": 100,
      "fields": [
        {
          "id": "1",
          "name": "id",
          "type": "BIGINT",
          "primary": true
        },
        {
          "id": "2",
          "name": "user_id",
          "type": "BIGINT",
          "notNull": true
        },
        {
          "id": "3",
          "name": "title",
          "type": "VARCHAR",
          "size": 200,
          "notNull": true
        }
      ]
    }
  ],
  "relationships": [
    {
      "id": "1",
      "source": "2",
      "target": "1",
      "sourceField": "user_id",
      "targetField": "id",
      "type": "many-to-one",
      "onDelete": "CASCADE"
    }
  ]
}

DrawDB Features

Table Properties

• id - Unique table identifier
• name - Table name
• x, y - Position in diagram
• fields - Array of field definitions
• indexes - Array of index definitions

Field Properties

• id - Unique field identifier
• name - Field name
• type - Data type (BIGINT, VARCHAR, etc.)
• size - Length for string types
• primary - Primary key flag
• notNull - NOT NULL constraint
• unique - Unique constraint
• autoIncrement - Auto-increment flag
• default - Default value

Relationship Properties

• id - Unique relationship identifier
• source - Source table ID
• target - Target table ID
• sourceField - Foreign key field
• targetField - Referenced field
• type - Relationship type (one-to-one, one-to-many, many-to-one)
• onDelete - Delete action
• onUpdate - Update action

Notes

• DrawDB is available at drawdb.vercel.app
• Generated files can be imported for visual editing
• Visual positions (x, y) are auto-generated
• Ideal for creating ERD diagrams
• Supports modern database features
• Free and open-source tool