reform

A better ORM for Go and database/sql.

It uses non-empty interfaces, code generation (go generate), and initialization-time reflection as opposed to interface{}, type system sidestepping, and runtime reflection. It will be kept simple.

Supported SQL dialects:

RDBMS	Library and drivers	Status
PostgreSQL	github.com/lib/pq (`postgres`)	Stable. Tested with all supported versions.
	github.com/jackc/pgx/stdlib (`pgx` v3)	Stable. Tested with all supported versions.
MySQL	github.com/go-sql-driver/mysql (`mysql`)	Stable. Tested with all supported versions.
SQLite3	github.com/mattn/go-sqlite3 (`sqlite3`)	Stable.
Microsoft SQL Server	github.com/denisenkom/go-mssqldb (`sqlserver`, `mssql`)	Stable. Tested on Windows with: SQL2008R2SP2, SQL2012SP1, SQL2014, SQL2016. On Linux with: `mcr.microsoft.com/mssql/server:2017-latest` and `mcr.microsoft.com/mssql/server:2019-latest` Docker images.

Notes:

clientFoundRows=true flag is required for mysql driver.
mssql driver is deprecated (but not sqlserver driver).

Quickstart

Make sure you are using Go 1.13+, and Go modules support is enabled. Install or update reform package, reform and reform-db commands with:
```
go get -v gopkg.in/reform.v1/...
```
If you are not using Go modules yet, you can use dep to vendor desired version of reform, and then install commands with:
```
go install -v ./vendor/gopkg.in/reform.v1/...
```
You can also install the latest stable version of reform without using Go modules thanks to gopkg.in redirection, but please note that this will not use the stable versions of the database drivers:
```
env GO111MODULE=off go get -u -v gopkg.in/reform.v1/...
```
Canonical import path is gopkg.in/reform.v1; using github.com/go-reform/reform will not work.

See note about versioning and branches below.
Use reform-db command to generate models for your existing database schema. For example:
```
reform-db -db-driver=sqlite3 -db-source=example.sqlite3 init
```
Update generated models or write your own – struct representing a table or view row. For example, store this in file person.go:
```
//go:generate reform

//reform:people
type Person struct {
	ID        int32      `reform:"id,pk"`
	Name      string     `reform:"name"`
	Email     *string    `reform:"email"`
	CreatedAt time.Time  `reform:"created_at"`
	UpdatedAt *time.Time `reform:"updated_at"`
}
```
Magic comment //reform:people links this model to people table or view in SQL database. The first value in field's reform tag is a column name. pk marks primary key. Use value - or omit tag completely to skip a field. Use pointers (recommended) or sql.NullXXX types for nullable fields.
Run reform [package or directory] or go generate [package or file]. This will create person_reform.go in the same package with type PersonTable and methods on Person.

See documentation how to use it. Simple example:

// Get *sql.DB as usual. PostgreSQL example:
sqlDB, err := sql.Open("postgres", "postgres://127.0.0.1:5432/database")
if err != nil {
	log.Fatal(err)
}
defer sqlDB.Close()

// Use new *log.Logger for logging.
logger := log.New(os.Stderr, "SQL: ", log.Flags())

// Create *reform.DB instance with simple logger.
// Any Printf-like function (fmt.Printf, log.Printf, testing.T.Logf, etc) can be used with NewPrintfLogger.
// Change dialect for other databases.
db := reform.NewDB(sqlDB, postgresql.Dialect, reform.NewPrintfLogger(logger.Printf))

// Save record (performs INSERT or UPDATE).
person := &Person{
	Name:  "Alexey Palazhchenko",
	Email: pointer.ToString("alexey.palazhchenko@gmail.com"),
}
if err := db.Save(person); err != nil {
	log.Fatal(err)
}

// ID is filled by Save.
person2, err := db.FindByPrimaryKeyFrom(PersonTable, person.ID)
if err != nil {
	log.Fatal(err)
}
fmt.Println(person2.(*Person).Name)

// Delete record.
if err = db.Delete(person); err != nil {
	log.Fatal(err)
}

// Find records by IDs.
persons, err := db.FindAllFrom(PersonTable, "id", 1, 2)
if err != nil {
	log.Fatal(err)
}
for _, p := range persons {
	fmt.Println(p)
}

Background

reform was born during summer 2014 out of frustrations with existing Go ORMs. All of them have a method Save(record interface{}) which can be used like this:

orm.Save(User{Name: "gopher"})
orm.Save(&User{Name: "gopher"})
orm.Save(nil)
orm.Save("Batman!!")

Now you can say that last invocation is obviously invalid, and that it's not hard to make an ORM to accept both first and second versions. But there are two problems:

Compiler can't check it. Method's signature in godoc will not tell us how to use it. We are essentially working against those tools by sidestepping type system.
First version is still invalid, since one would expect Save() method to set record's primary key after INSERT, but this change will be lost due to passing by value.

First proprietary version of reform was used in production even before go generate announcement. This free and open-source version is the fourth milestone on the road to better and idiomatic API.

Versioning and branching policy

We are following Semantic Versioning, using gopkg.in and filling a changelog. All v1 releases are SemVer-compatible; breaking changes will not be applied.

We use tags v1.M.m for releases, branch main (default on GitHub) for the next minor release development, and release/1.M branches for patch release development. (It was more complicated before 1.4.0 release.)

Major version 2 is currently not planned.

Additional packages

github.com/AlekSi/pointer is very useful for working with reform structs with pointers.

Caveats and limitations

There should be zero pk fields for Struct and exactly one pk field for Record. Composite primary keys are not supported (#114).
pk field can't be a pointer (== nil doesn't work).
Database row can't have a Go's zero value (0, empty string, etc.) in primary key column.

License

The reform gopher was drawn by Natalya Glebova. Please use it only as reform logo. It is based on the original design by Renée French, released under Creative Commons Attribution 3.0 USA license.

Contributing

See Contributing Guidelines.

romanitalian/reform