I would like to know if it is possible to preload data from both sides of a relationship. Consider this example:
type User struct {
gorm.Model
Name string
Documents []Document // has-many
}
type Document struct {
gorm.Model
UserID uint
Name string
DocumentFulltext DocumentFulltext // has-one
}
type DocumentFulltext struct {
gorm.Model
DocumentID uint
Name string
}
With that I can easily get the DocumentFulltext for any given document like this
db.Where("id = ?", ID).Preload("DocumentFulltext").Find(&document)
Works!
But what if I have the document and want to preload (or join) the User it belongs to?
db.Where("id = ?", ID).Preload("User").Find(&document)
That gives me a panic. ( invalid memory address
)
db.Where("id = ?", ID).Joins("User").Find(&document)
And that produces wonky SQL like .... FROM "documents" User WHERE id =...
How is this possible? Do I need to use "manual" queries?
--
If it is not possible: what is a good-practice / guideline how to model my relationships so I can use GORM built-ins like.Preload() effectively?
Eg If I put the relationship between Users and Documents like this:
type User struct {
gorm.Model
Name string
}
type Document struct {
gorm.Model
User User // belongs-to
UserID uint
Name string
DocumentFulltext DocumentFulltext // has-one
}
type DocumentFulltext struct {
gorm.Model
DocumentID uint
Name string
}
then I can preload both, DocumentFulltext AND User, for any given Document. But I loose the ability the preload Documents and Fulltexts if I want to do it for a given User.
--
Any hints a re appreciated. Thx!
Use relation both side means User
in Document
struct and Documents
in User
struct
type User struct {
gorm.Model
Name string
Documents []Document // has-many
}
type Document struct {
gorm.Model
UseredID uint
Name string
User User
}
Then you can preload both sides
db.Debug().Where("id = ?", ID).Preload("User").Find(&document)
db.Debug().Where("id = ?", ID).Preload("Documents").Find(&user)
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