130 lines
3.3 KiB
Markdown
130 lines
3.3 KiB
Markdown
# Bun Writer
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Generates Go source files with Bun model definitions from database schema information.
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## Overview
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The Bun Writer converts RelSpec's internal database model representation into Go source code with Bun struct definitions, complete with proper tags, relationships, and table configuration.
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## Features
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- Generates Bun-compatible Go structs
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- Creates proper `bun` struct tags
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- Adds relationship fields
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- Supports both single-file and multi-file output
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- Maps SQL types to Go types
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- Handles nullable fields with sql.Null* types
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- Generates table aliases
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## Usage
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### Basic Example
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```go
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package main
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import (
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"git.warky.dev/wdevs/relspecgo/pkg/models"
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"git.warky.dev/wdevs/relspecgo/pkg/writers"
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"git.warky.dev/wdevs/relspecgo/pkg/writers/bun"
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)
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func main() {
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options := &writers.WriterOptions{
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OutputPath: "models.go",
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PackageName: "models",
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}
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writer := bun.NewWriter(options)
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err := writer.WriteDatabase(db)
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if err != nil {
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panic(err)
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}
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}
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```
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### CLI Examples
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```bash
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# Generate Bun models from PostgreSQL database
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relspec --input pgsql \
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--conn "postgres://localhost/mydb" \
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--output bun \
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--out-file models.go \
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--package models
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# Convert GORM models to Bun
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relspec --input gorm --in-file gorm_models.go --output bun --out-file bun_models.go
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# Multi-file output
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relspec --input json --in-file schema.json --output bun --out-file models/
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```
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## Generated Code Example
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```go
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package models
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import (
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"time"
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"database/sql"
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"github.com/uptrace/bun"
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)
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type User struct {
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bun.BaseModel `bun:"table:users,alias:u"`
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ID int64 `bun:"id,pk,autoincrement" json:"id"`
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Username string `bun:"username,notnull,unique" json:"username"`
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Email string `bun:"email,notnull" json:"email"`
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Bio sql.NullString `bun:"bio" json:"bio,omitempty"`
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CreatedAt time.Time `bun:"created_at,notnull,default:now()" json:"created_at"`
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// Relationships
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Posts []*Post `bun:"rel:has-many,join:id=user_id" json:"posts,omitempty"`
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}
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type Post struct {
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bun.BaseModel `bun:"table:posts,alias:p"`
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ID int64 `bun:"id,pk" json:"id"`
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UserID int64 `bun:"user_id,notnull" json:"user_id"`
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Title string `bun:"title,notnull" json:"title"`
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Content sql.NullString `bun:"content" json:"content,omitempty"`
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// Belongs to
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User *User `bun:"rel:belongs-to,join:user_id=id" json:"user,omitempty"`
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}
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```
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## Supported Bun Tags
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- `table` - Table name and alias
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- `column` - Column name (auto-derived if not specified)
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- `pk` - Primary key
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- `autoincrement` - Auto-increment
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- `notnull` - NOT NULL constraint
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- `unique` - Unique constraint
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- `default` - Default value
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- `rel` - Relationship definition
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- `type` - Explicit SQL type
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## Type Mapping
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| SQL Type | Go Type | Nullable Type |
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|----------|---------|---------------|
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| bigint | int64 | sql.NullInt64 |
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| integer | int | sql.NullInt32 |
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| varchar, text | string | sql.NullString |
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| boolean | bool | sql.NullBool |
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| timestamp | time.Time | sql.NullTime |
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| numeric | float64 | sql.NullFloat64 |
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## Notes
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- Model names are derived from table names (singularized, PascalCase)
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- Table aliases are auto-generated from table names
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- Multi-file mode: one file per table named `sql_{schema}_{table}.go`
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- Generated code is auto-formatted
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- JSON tags are automatically added
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