Code-First ORM For Go: GORM

Code-First ORM For Go: GORM

Check out the video for some more elaboration on the topics below.

If you liked it and want to know when I post more videos, be sure to subscribe

Time to start looking at some ORMs for go, today we're gonna start with gorm. Gorm is a code-first ORM, meaning we can use go code to define our database scheme, run the migrations, and also interact with the database with the same code.

Connect to the Database

In order to connect to a database using gorm, we simply use the following:

db, err := gorm.Open("sqlite3", "test.db")
if err != nil {
  // Handle error
defer db.Close()

We are opening a sqlite3 file because I didn't want to fiddle with something like MySQL for this.

We handle an error if one occurred, and defer a call to db.Close() to ensure the connection is cleaned up afterward

Defining Schema with Structs

We have the following structs:

type Channel struct {
	Name        string
	Description string

type User struct {
	Email    string
	Username string

type Message struct {
	Content   string
	UserID    uint
	ChannelID uint
	User      User
	Channel   Channel

Each of these structs will have a corresponding table in our database, with the same columns as the structs have properties.

The gorm.Model struct has some standard properties commonly used in SQL database, check out the docs to see more about it.

You'll notice the Message struct has properties that reference other structs. These are used to map the table relations, read more about how gorm does relationship mapping here.


The easiest way to sync up our schema to our structs is to use the AutoMigration method defined on the db instance:

db.AutoMigrate(&Channel{}, &User{}, &Message{})

We pass in an instance of each struct and gorm does some reflection under the hood to make any schema changes, generate the queries, and run them.

Keep in mind, AutoMigrate will only add missing tables, columns, and indexes. It will not remove unused ones, read why here.

Adding Data

To create a new row in our database, we simply create an instance of one of our structs, set the values on its properties, and pass it to the Create method on our database connection:

channel := Channel{Name: "General", Description: "General banter"}


Tada, data has been inserted into our table!

Finding Data

If you want to grab something from the database, the docs have a lot of examples but some notable ones are as follows:

// give me all the channels and unmarshal them into my variable channels, which is of type []Channel

// give me the first record by primary key, in the channels table and unmarshal it into my variable channel, which is of type Channel

// same as db.First() but gets the last record by primary key

You can also build where clauses using the Where method:

// Adds a 'where name = "General"' clause to the select query
db.Where("Name = ?", "General").Find(&channels)

// You can pass in structs to act as the where clause source.
// Here it will take the field 'Name' from our channel struct and add it into the where clause
db.Where(&Channel{Name: "General"}).First(&channel)

Error Handling

Gorm handles errors in a way that is a little different than idiomatic go.

After you run a gorm query, it will set a value to the Error variable in the gorm package, if an error occurred while running the query.

Here is an example of checking if the method ended up returning an error:

if err := db.Where("Name = ?", "MissingName").First(&channel).Error; err != nil {
  // Handle error


Gorm makes it fairly easy to manage your database schema and acts as an abstraction over your database backend.

Thank you for reading

Did you find this information useful? If so, consider heading over to my donation page and drop me some support.

Want to ask a question or just chat? Contact me here