modelgen-cli

README

modelgen-cli

CLI tool to generate GORM-ready models, entities, and migrations in Go projects.

Author: M.RIZKI ISWANTO GitHub: github.com/REXY4/modelgen-cli

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Dependencies

• gorm.io/gorm

  • Purpose: Object-Relational Mapping (ORM) for Go.
  • In CLI: Generated models are ready to use with GORM, including ID, CreatedAt, UpdatedAt, DeletedAt, and GORM tags like gorm:"column:..." and gorm:"primaryKey".
  • Website: https://gorm.io

• Standard Go libraries: os, strings, flag, fmt, log, time.

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CLI Options

--name string        # Model name, e.g.: User
--attributes string  # Model attributes, e.g.: name:string,email:string
--folder string      # Base folder of the project (default: ".")
--relations string   # Relations, e.g.: Products:Product:one2many,Tags:Tag:many2many
--init               # Generate configs/db.go for supported databases
--db string          # Database type: postgres, mysql, sqlite, sqlserver (default: postgres)

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Usage

1. Install via go install

go install github.com/REXY4/modelgen-cli@latest

2. Initialize database config

# PostgreSQL
modelgen-cli --init --db postgres

# MySQL
modelgen-cli --init --db mysql

# SQLite
modelgen-cli --init --db sqlite

# SQL Server
modelgen-cli --init --db sqlserver

3. Generate a model

modelgen-cli --name User --attributes name:string,email:string,age:int

• Creates:
  • configs/db.go
  • internal/models/<Model Name>.go
  • internal/entity/<Entity Name>.go
  • internal/migrations/<timestamp>_create_<Migration Name>.go

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• Creates configs/db.go for the chosen database.
• Supported databases: postgres, mysql, sqlite, sqlserver.
• Automatically configures GORM connection using DSN.

4. Generate a model

modelgen-cli --name User --attributes name:string,email:string

5. Add relations (optional)

modelgen-cli --name User --attributes name:string,email:string,age:int \
  --relations Products:Product:one2many,Tags:Tag:many2many

• Updates internal/models/user.go to include:

Products []Product `gorm:"foreignKey:UserID"`
Tags     []Tag     `gorm:"many2many:user_tag"`

Supported Data Types

1. String Types

Name	Go Type	GORM Tag Example
string	string	gorm:"column:name"
text	string	gorm:"type:text"
varchar(n)	string	gorm:"size:n"

Note: text and varchar differ only in the database; in Go they are both string.

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2. Numeric Types

Name	Go Type	GORM Tag Example
int	int	gorm:"column:age"
int8	int8	gorm:"column:small_number"
int16	int16	gorm:"column:small_number"
int32	int32	gorm:"column:number"
int64	int64	gorm:"column:number"
uint	uint	gorm:"column:id;primaryKey"
float	float64	gorm:"column:price"
float32	float32	gorm:"column:price"
decimal	float64	gorm:"type:decimal(10,2)"

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3. Boolean Type

Name	Go Type	GORM Tag Example
bool	bool	gorm:"column:is_active"

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4. Time / Date Types

Name	Go Type	GORM Tag Example
datetime	time.Time	gorm:"column:created_at"
timestamp	time.Time	gorm:"column:updated_at"
date	time.Time	gorm:"type:date"

GORM usually auto-generates CreatedAt, UpdatedAt, DeletedAt timestamps.

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5. JSON / Array Types

Name	Go Type	GORM Tag Example
json	datatypes.JSON	gorm:"type:json"
string[]	pq.StringArray	gorm:"type:text[]"

Requires imports:

import "gorm.io/datatypes"
import "github.com/lib/pq"

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6. Relations (special attributes)

Relation Type	Go Type Example	GORM Tag Example
One-to-One	Profile	gorm:"foreignKey:UserID"
One-to-Many	[]Product	gorm:"foreignKey:UserID"
Many-to-Many	[]Tag	gorm:"many2many:user_tag"

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7. Migration Usage

After generating models with migrations:

import "yourapp/internal/migrations"

func main() {
    migrations.MigrateAll()    // Run all migrations
    // migrations.RollbackAll() // Rollback all tables if needed
}

• MigrateAll() runs Up<Model>() for each generated model.
• RollbackAll() runs Down<Model>() for each generated model.

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