github.com/rniedosmialek/tables-to-go

Tables-to-Go

convert your database tables to structs easily

A small and convenient tool supporting development against a changing database schema.

Tables change, run the tool, get your structs!

Requirements

• Go 1.17+

Install

This project provides a make file but can also simply be installed with the go-install command:

go install github.com/fraenky8/tables-to-go@master

To enable SQLite3 support, clone the repo manually and run the make file:

make sqlite3

See this PR why it's disabled by default.

Getting Started

tables-to-go -v -of ../path/to/my/models

This gets all tables of a local running PostgreSQL database. Therefore, it uses the database postgres, schema public and user postgres with no password. Flag -v is verbose mode, -of is the output file path where the go files containing the structs will get created (default: current working directory).

Features

• convert your tables to structs
• table with name a_foo_bar will become file AFooBar.go with struct AFooBar
• properly formatted files with imports
• automatically typed struct fields, either with sql.Null* or primitive pointer types
• struct fields with db-tags for ready to use in database code
• partial support for Masterminds/structable
  • only primary key & auto increment columns supported
  • struct fields with stbl tags
  • ability to generate structs only for Masterminds/structable:
    • without db-tags
    • with or without structable.Recorder
• currently supported:
  • PostgreSQL (9.5 tested)
  • MySQL (5.5+, 8 tested)
  • SQLite (3 tested)
• currently, the following basic data types are supported:
  • numeric: integer, serial, double, real, float
  • character: varying, text, char, varchar, binary, varbinary, blob
  • date/time: timestamp, date, datetime, year, time with time zone, timestamp with time zone, time without time zone, timestamp without time zone
  • others: boolean

Examples

Assuming you have the following table definition (PostgreSQL):

CREATE TABLE some_user_info  (
  id SERIAL NOT NULL PRIMARY KEY,
  first_name VARCHAR(20),
  last_name  VARCHAR(20) NOT NULL,
  height DECIMAL
);

Run the following command (default local PostgreSQL instance):

tables-to-go

The following file SomeUserInfo.go with default package dto (data transfer object) will be created:

package dto

import (
	"database/sql"
)

type SomeUserInfo struct {
	ID        int             `db:"id"`
	FirstName sql.NullString  `db:"first_name"`
	LastName  string          `db:"last_name"`
	Height    sql.NullFloat64 `db:"height"`
}

The column id got automatically converted to upper-case to follow the idiomatic go guidelines. See here for more details. Words which gets converted can be found here.
This behaviour can be disabled by providing the command-line flag -no-initialism.

Running on remote database server (eg. Mysql@Docker)

tables-to-go -v -t mysql -h 192.168.99.100 -d testdb -u root -p mysecretpassword

PostgreSQL example with different default schema but default database postgres:

tables-to-go -v -t pg -h 192.168.99.100 -s test -u postgres -p mysecretpassword

Note: since database type pg is default, following command will be equivalent:

tables-to-go -v -h 192.168.99.100 -s test -u postgres -p mysecretpassword

You can also specify the package or prefix and suffix.

tables-to-go -v -t mysql -h 192.168.99.100 -d testdb -u root -p mysecretpassword -pn models -pre model_ -suf _model

With same table given above, following file with Name ModelSomeUserInfoModel.go will be created:

package models

import (
	"database/sql"
)

type ModelSomeUserInfoModel struct {
	ID        int             `db:"id"`
	FirstName sql.NullString  `db:"first_name"`
	LastName  string          `db:"last_name"`
	Height    sql.NullFloat64 `db:"height"`
}

Where Are The JSON-Tags?

This is a common question asked by contributors and bug reporters.

Fetching data from a database and representation of this data in the end (JSON, HTML template, cli, ...) are two different concerns and should be decoupled. Therefore, this tool will not generate json tags for the structs.

There are tools like gomodifytags which enables you to generate json tags for existing structs. The call for this tool applied to the example above looks like the following:

gomodifytags -file SomeUserInfo.go -w -all -add-tags json

This adds the json tags directly to the file:

type SomeUserInfo struct {
	ID        int             `db:"id" json:"id"`
	FirstName sql.NullString  `db:"first_name" json:"first_name"`
	LastName  string          `db:"last_name" json:"last_name"`
	Height    sql.NullFloat64 `db:"height" json:"height"`
}

Command-line Flags

Print usage with -? or -help

Usage of tables-to-go:
  -?	shows help and usage
  -d string
    	database name (default "postgres")
  -f	force; skip tables that encounter errors
  -fn-format string
    	format of the filename: camelCase (c, default) or snake_case (s) (default c)
  -format string
    	format of struct fields (columns): camelCase (c) or original (o) (default c)
  -h string
    	host of database (default "127.0.0.1")
  -help
    	shows help and usage
  -no-initialism
    	disable the conversion to upper-case words in column names
  -null string
    	representation of NULL columns: sql.Null* (sql) or primitive pointers (native|primitive) (default sql)
  -of string
    	output file path (default "current working directory")
  -p string
    	password of user
  -pn string
    	package name (default "dto")
  -port string
    	port of database host, if not specified, it will be the default ports for the supported databases
  -pre string
    	prefix for file- and struct names
  -s string
    	schema name (default "public")
  -socket string
    	The socket file to use for connection. Takes precedence over host:port.
  -structable-recorder
    	generate a structable.Recorder field
  -suf string
    	suffix for file- and struct names
  -t string
    	type of database to use, currently supported: [pg mysql sqlite3] (default pg)
  -tags-no-db
    	do not create db-tags
  -tags-structable
    	generate struct with tags for use in Masterminds/structable (https://github.com/Masterminds/structable)
  -tags-structable-only
    	generate struct with tags ONLY for use in Masterminds/structable (https://github.com/Masterminds/structable)
  -u string
    	user to connect to the database (default "postgres")
  -v	verbose output
  -vv
    	more verbose output

Contributing

If you find any issues or missing a feature, feel free to contribute or make suggestions! You can fork the repository and use a feature branch too. Feel free to send me a pull request. The PRs have to come with appropriate unit tests, documentation of the added functionality and updated README with optional examples.

To start developing clone via git or use go's get command to fetch this project.

This project uses go modules so make sure when adding new dependencies to update the go.mod file and the vendor directory:

go mod tidy
go mod vendor

Licensing

The code in this project is licensed under MIT license.