f06d6412de
When using `Preload` to include the results of a "has many"
relationship, Gorm previously returned an uninitialized slice for any
such relations that bore zero records. This distinction was most
apparent when the results were marshalled to a JSON representation--a
record with zero related records would be represented with `null`.
For example, consider the following schema:
id | name
---|------
1 | Lorin
2 | Sue
id | p_id | value
---|------|-------------------
1 | 1 | lorin@example.com
2 | 1 | lorin2@example.com
Querying with:
db.Preload("Email").Find(&people)
And marshalling the resulting value of `people` to JSON would yield the
following string:
[
{
"name": "Lorin",
"email": [
"lorin@example.com",
"lorin2@example.com"
]
},
{
"name": "Sue",
"email": null
}
]
Beyond being inconsistent, the value `null` in this response differs
semantically from the actual state of the database. The database
actually has zero related records for the second user, so a JSON value
of `[]` is appropriate.
Update the callback that processes "has many" relationships to
communicate empty query results with an empty slice.
GORM
The fantastic ORM library for Golang, aims to be developer friendly.
Overview
- Full-Featured ORM (almost)
- Associations (Has One, Has Many, Belongs To, Many To Many, Polymorphism)
- Callbacks (Before/After Create/Save/Update/Delete/Find)
- Preloading (eager loading)
- Transactions
- Composite Primary Key
- SQL Builder
- Auto Migrations
- Logger
- Extendable, write Plugins based on GORM callbacks
- Every feature comes with tests
- Developer Friendly
Getting Started
- GORM Guides jinzhu.github.com/gorm
Upgrading To V1.0
Author
jinzhu
Contributors
https://github.com/jinzhu/gorm/graphs/contributors
License
Released under the MIT License.