162 lines
3.2 KiB
Markdown
162 lines
3.2 KiB
Markdown
# DBML Writer
|
|
|
|
Generates Database Markup Language (DBML) files from database schema information.
|
|
|
|
## Overview
|
|
|
|
The DBML Writer converts RelSpec's internal database model representation into DBML syntax, suitable for use with dbdiagram.io and other DBML-compatible tools.
|
|
|
|
## Features
|
|
|
|
- Generates DBML syntax
|
|
- Creates table definitions with columns
|
|
- Defines relationships
|
|
- Includes indexes
|
|
- Adds notes and documentation
|
|
- Supports enums
|
|
|
|
## Usage
|
|
|
|
### Basic Example
|
|
|
|
```go
|
|
package main
|
|
|
|
import (
|
|
"git.warky.dev/wdevs/relspecgo/pkg/models"
|
|
"git.warky.dev/wdevs/relspecgo/pkg/writers"
|
|
"git.warky.dev/wdevs/relspecgo/pkg/writers/dbml"
|
|
)
|
|
|
|
func main() {
|
|
options := &writers.WriterOptions{
|
|
OutputPath: "schema.dbml",
|
|
}
|
|
|
|
writer := dbml.NewWriter(options)
|
|
err := writer.WriteDatabase(db)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
}
|
|
```
|
|
|
|
### CLI Examples
|
|
|
|
```bash
|
|
# Generate DBML from PostgreSQL database
|
|
relspec --input pgsql \
|
|
--conn "postgres://localhost/mydb" \
|
|
--output dbml \
|
|
--out-file schema.dbml
|
|
|
|
# Convert GORM models to DBML
|
|
relspec --input gorm --in-file models.go --output dbml --out-file database.dbml
|
|
|
|
# Convert JSON to DBML for visualization
|
|
relspec --input json --in-file schema.json --output dbml --out-file diagram.dbml
|
|
```
|
|
|
|
## Generated DBML Example
|
|
|
|
```dbml
|
|
Project MyDatabase {
|
|
database_type: 'PostgreSQL'
|
|
}
|
|
|
|
Table users {
|
|
id bigserial [pk, increment]
|
|
username varchar(50) [not null, unique]
|
|
email varchar(100) [not null]
|
|
bio text [null]
|
|
created_at timestamp [not null, default: `now()`]
|
|
|
|
Note: 'Users table'
|
|
|
|
indexes {
|
|
email [name: 'idx_users_email']
|
|
}
|
|
}
|
|
|
|
Table posts {
|
|
id bigserial [pk, increment]
|
|
user_id bigint [not null]
|
|
title varchar(200) [not null]
|
|
content text [null]
|
|
created_at timestamp [default: `now()`]
|
|
|
|
indexes {
|
|
user_id [name: 'idx_posts_user_id']
|
|
(user_id, created_at) [name: 'idx_posts_user_created']
|
|
}
|
|
}
|
|
|
|
Ref: posts.user_id > users.id [delete: cascade, update: no action]
|
|
```
|
|
|
|
## DBML Features
|
|
|
|
### Table Definitions
|
|
```dbml
|
|
Table table_name {
|
|
column_name type [attributes]
|
|
}
|
|
```
|
|
|
|
### Column Attributes
|
|
- `pk` - Primary key
|
|
- `increment` - Auto-increment
|
|
- `not null` - NOT NULL constraint
|
|
- `null` - Nullable (explicit)
|
|
- `unique` - Unique constraint
|
|
- `default: value` - Default value
|
|
- `note: 'text'` - Column note
|
|
|
|
### Relationships
|
|
```dbml
|
|
Ref: table1.column > table2.column
|
|
Ref: table1.column < table2.column
|
|
Ref: table1.column - table2.column
|
|
```
|
|
|
|
Relationship types:
|
|
- `>` - Many-to-one
|
|
- `<` - One-to-many
|
|
- `-` - One-to-one
|
|
|
|
Relationship actions:
|
|
```dbml
|
|
Ref: posts.user_id > users.id [delete: cascade, update: restrict]
|
|
```
|
|
|
|
### Indexes
|
|
```dbml
|
|
indexes {
|
|
column_name
|
|
(column1, column2) [name: 'idx_name', unique]
|
|
}
|
|
```
|
|
|
|
## Type Mapping
|
|
|
|
| SQL Type | DBML Type |
|
|
|----------|-----------|
|
|
| bigint | bigint |
|
|
| integer | int |
|
|
| varchar(n) | varchar(n) |
|
|
| text | text |
|
|
| boolean | boolean |
|
|
| timestamp | timestamp |
|
|
| date | date |
|
|
| json | json |
|
|
| uuid | uuid |
|
|
|
|
## Notes
|
|
|
|
- DBML is designed for database visualization
|
|
- Can be imported into dbdiagram.io
|
|
- Human-readable format
|
|
- Schema names can be included in table names
|
|
- Comments and notes are preserved
|
|
- Ideal for documentation and sharing designs
|