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:

• PostgreSQL (tested with github.com/lib/pq).
• MySQL (tested with github.com/go-sql-driver/mysql).
• SQLite3 (tested with github.com/mattn/go-sqlite3).
• Microsoft SQL Server (tested with github.com/denisenkom/go-mssqldb).

Quickstart

1. Make sure you are using Go 1.6+.

2. Install or update it: go get -u gopkg.in/reform.v1/reform (see about versioning below)

3. Define your first model 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. First value in reform tag is a column name. pk marks primary key. Use pointers for nullable fields.

4. 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.

5. See documentation how to use it. Simple example:

   // Use reform.NewDB to create DB.
   
   // 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:

1. 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.
2. 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 policy

We are following Semantic Versioning, using gopkg.in and filling a changelog.

We use branch v1-stable (default on Github) for v1 development and tags v1.Y.Z for releases. All v1 releases are SemVer-compatible, breaking changes will not be applied. Canonical import path is gopkg.in/reform.v1. go get -u gopkg.in/reform.v1 will install latest released version. To install not yet released v1 version one can do checkout manually while preserving import path:

go get -u gopkg.in/reform.v1
cd $GOPATH/gopkg.in/reform.v1
git checkout origin/v1-stable

Branch v2-unstable is used for v2 development. It doesn't have any releases yet, and no compatibility is guaranteed. Canonical import path is gopkg.in/reform.v2-unstable.

Additional packages

• github.com/AlekSi/pointer is very useful for working with reform structs with pointers.
• github.com/mc2soft/pq-types is a collection of PostgreSQL types, we use it with reform.

Caveats

• There should be zero pk fields for Struct and exactly one pk field for Record.
• 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.