Error Handling

In Go, error handling is important.

You are encouraged to do error check after any Immediate Methods

Error Handling

Error handling in GORM is different than idiomatic Go code because of its chainable API, but still easy to implement.

If any error occurs, GORM will set *gorm.DB‘s Error field, which you can check like this:

if err := db.Where("name = ?", "jinzhu").First(&user).Error; err != nil {
  // error handling...
}

Or

if result := db.Where("name = ?", "jinzhu").First(&user); result.Error != nil {
  // error handling...
}

Errors

When processing data, it is common for multiple errors to occur. GORM provides an API to return all errors as a slice:

// If there are more than one error happened, `GetErrors` returns them as `[]error`
errors := db.First(&user).Limit(10).Find(&users).GetErrors()

fmt.Println(len(errors))

for _, err := range errors {
  fmt.Println(err)
}

RecordNotFound Error

GORM provides a shortcut to handle RecordNotFound errors. If there are several errors, it will check if any of them is a RecordNotFound error.

// Check if returns RecordNotFound error
db.Where("name = ?", "hello world").First(&user).RecordNotFound()

if db.Model(&user).Related(&credit_card).RecordNotFound() {
  // record not found
}

if err := db.Where("name = ?", "jinzhu").First(&user).Error; gorm.IsRecordNotFoundError(err) {
  // record not found
}