I am trying to pull data for CountyEntity that related with CityEntity:
type CityEntity struct {
tableName struct{} `pg:"city,alias:ci,discard_unknown_columns"`
Id string `pg:"id"`
Name string `pg:"name"`
}
type CountyEntity struct {
tableName struct{} `pg:"county,alias:co,discard_unknown_columns"`
Id int64 `pg:"id"`
Name string `pg:"name"`
DefaultTargetXDockId int64 `pg:"defaulttargetxdockid"`
MapsPreference string `pg:"mapspreference"`
EmptyDistrictAllowed bool `pg:"empty_district_allowed"`
CityId int64 `pg:"cityid"`
City *CityEntity `pg:"fk:cityid"`
}
My query is:
db, _ := repository.pgRepository.CreateDBConnection(.....)
var counties []model.CountyEntity
err := db.Model(&counties).
Join("inner join test.city ci on ci.id = co.cityid").
Relation("City").
Where("co.cityid = ?", cityId).
Select()
return counties, err
it throws that:
model=CountyEntity does not have relation="City"
But actually, I have the relation between city and county table on the database.
Db Relation Image
I tried different ways to solve but I couldn't solve it. Does anybody have an idea about what is the root cause of it and what is the possible solutions?
Pretty old and I'm sure you've figured it out by now, but for anyone else that stumbles across this your model should look like this
type CountyEntity struct {
tableName struct{} `pg:"county,alias:co,discard_unknown_columns"`
Id int64 `pg:"id"`
Name string `pg:"name"`
DefaultTargetXDockId int64 `pg:"defaulttargetxdockid"`
MapsPreference string `pg:"mapspreference"`
EmptyDistrictAllowed bool `pg:"empty_district_allowed"`
CityId int64 `pg:"cityid"`
City *CityEntity `pg:"rel:has-one,fk:cityid"`
}
Notice the "rel:has-one" added to the city column. You can find more information about all of these here: https://pg.uptrace.dev/models/
Related
I'm having troubles with one-to-many associations in GORM.
I have those two structures and I'd like to get one patient's full history. Here is my sample code:
type Patient struct {
gorm.Model
Prenom string `json:"prenom" gorm:"column:patient_prenom"`
Nom string `json:"nom" gorm:"column:patient_nom"`
Genre string `json:"genre" gorm:"column:patient_genre"`
Naissance string `json:"naissance" gorm:"column:patient_naissance"`
Historique []Historique `gorm:"ForeignKey:Fk_patient_id"`
}
type Historique struct {
Fk_patient_id string
Date_consultation string
Fk_maladie_id uint
Fk_compte_medecin_id uint
Patient Patient
}
func GetPatientWithDiseases(id uint) (*Patient, error) {
patient := &Patient{}
//The line right there works so i can retrieve without the history
//err := GetDB().Find(patient, id).Error
db := GetDB().Preload("tt_historique").Find(patient)
err := db.Error
if err != nil {
return nil, err
}
return patient, nil
}
Where "Historique" uses the foreign key of the patient (Fk_patient_id), and the Historique []Historique is the list of every Historique that should end up in the Patient struct after the query.
However I get this error can't preload field tt_historique for models.Patient. I've tried multiple syntaxes that I've found on Internet in the gorm specifications in the struct but nothing worked. I've only been developing using GO for 3 days and GORM is my first ORM, so maybe I'm missing something really obvious.
Based on the presumption that tt_historique is your table name, there are a couple of things you need to take care of here.
By convention, go-gorm uses pluralized snake case struct names as database tables when constructing a SQL query. In your case, to preload the Historique []Historique field, it would look for the historiques table.
To override this, you need to implement the Tabler interface:
type Patient struct {
gorm.Model
Prenom string `json:"prenom" gorm:"column:patient_prenom"`
Nom string `json:"nom" gorm:"column:patient_nom"`
Genre string `json:"genre" gorm:"column:patient_genre"`
Naissance string `json:"naissance" gorm:"column:patient_naissance"`
Historique []Historique `gorm:"foreignKey:Fk_patient_id"`
}
type Historique struct {
Fk_patient_id string
Date_consultation string
Fk_maladie_id uint
Fk_compte_medecin_id uint
Patient Patient
}
func (Historique) TableName() string {
return "tt_historique"
}
Then, your query would look like this:
db := GetDB().Preload("Historique").Find(patient)
This query here below works, where the where clause works becuase it's using values from ResourceUsage struct, but I would love to be able to do something like this, where the where clause is using value from the ResourceMetadata struct.
db.Preload("ResourceMetadata").Where("resource_type = ?", resourceType).Where("timestamp BETWEEN ? AND ?", start, end).Limit(10).Find(&resourceUsage)
But it throws exception:
2019-12-03 11:06:12] Error 1054: Unknown column 'resource_type' in 'where clause'
Code:
// ResourceUsage describes the storage model for resource-usage
type ResourceUsage struct {
ID int64 `json:"-"`
DetailsID int64 `json:"details_id"`
ResourceMetadata *ResourceMetadata `gorm:"foreignkey:DetailsID;association_foreignkey:ID"`
MeasuredType string `json:"measured_type"`
Quantity float64 `json:"quantity"`
Timestamp int64 `json:"timestamp"`
}
// ResourceMetadata describes the storage model for resource-usage
type ResourceMetadata struct {
ID int64 `json:"-"`
ResourceUUID string `json:"resource_uuid"`
ResourceName string `json:"resource_name"`
ResourceDisplayName string `json:"resource_display_name"`
ResourceType string `json:"resource_type"`
}
db.Preload("ResourceMetadata").Where("timestamp BETWEEN ? AND ?", start, end).Limit(10).Find(&resourceUsage)
Can you use a JOIN?
resourceUsages := []ResourceUsage{}
if err := db.Joins("JOIN resource_metadata ON resource_metadata.id=details_id").
Where("resource_metadata.resource_type = ? AND timestamp BETWEEN ? AND ?", resourceType, start, end).
Preload("ResourceMetadata").Limit(10).
Find(&resourceUsages).Error; err != nil {
// ... handle error ...
}
The idea is to design a table/entity that contains some basic info, as well as a Markdown-Content field that would allow users to easily create tables and such.
I'm thinking something like this:
type Tournament struct {
ID in64 `datastore:"-"`
MDContent []byte `datastore:",noindex"`
Name string
URL string
DateCreated int64
CreatedBy string
DateUpdated int64
UpdatedBy string
ApprovalStatus int64 // 0=to be decided, 1=approved, 2=rejected, 3=discontinued
ApprovalBy string
}
My problem is figuring out how to update it. The ID field will also be used as the URL path, e.g. if an entity has ID 7 then it will be displayed on example.com/tournament/7.
I believe this eliminates the possibility of simply creating a new entity with updated data, and then set the ApprovalStatus=3 on the previous entity, because if you do as such then the example.com/tournament/7 URL will no longer request the correct ID.
I also don't like the idea of creating my own unique ID because I think it would be great to simply take advantage of the Datastore ID generation (which also makes it easy to get the correct entity based on URL); I considered creating a new entity/table that would keep track of revisions but I'm not sure how efficient all of this is, so I was hoping some expert might be able to give some advice.
Update related to #mkopriva solution:
If you do it this way, then it's necessary to include a TournamentID field inside the TournamentEdit entity struct I think?
type TournamentEdit struct {
ID in64 `datastore:"-"`
TournamentID int64
MDContent []byte `datastore:",noindex"`
DateCreated int64
CreatedBy string
ApprovalStatus int64 // 0=to be decided, 1=approved, 2=rejected, 3=discontinued
ApprovalBy string
}
And then the retrieve function could look like this:
func (db *datastoreDB) GetTournamentByKeyID(ctx context.Context, keyID int64) (*Tournament, error) {
key := datastore.IDKey("Tournament", keyID, nil)
var tournamnet Tournament
err := db.client.Get(ctx, key, &tournament)
// err checking
tournament.ID = key.ID
var edits TournamentEdits
query := datastore.NewQuery("TournamentEdit")
query = query.Filter("TournamentID =", tournament.ID)
query = query.Filter("ApprovalStatus =", 1)
if _, err := db.client.GetAll(ctx, query, &edits); err != nil {
//err checking
}
tournament.Edits = edits // I guess this is wrong way to do it?
return &tournament, nil
}
Would this work?
One thing you could do is to simply create a new entity that would represent the edit of a tournament. By the way, I'm not a datastore user so I'm not sure if this is how you would model the entities but the general idea is the same for most, if not all, databases:
type Tournament struct {
ID in64 `datastore:"-"`
MDContent []byte `datastore:",noindex"`
Name string
URL string
DateCreated int64
CreatedBy string
DateUpdated int64
UpdatedBy string
Edits []TournamentEdit
}
type TournamentEdit struct {
ID in64 `datastore:"-"`
MDContent []byte `datastore:",noindex"`
DateCreated int64
CreatedBy string
ApprovalStatus int64 // 0=to be decided, 1=approved, 2=rejected, 3=discontinued
ApprovalBy string
}
This should allow you to have multiple edits from different users in the queue, CRUD a specific edit, and or filter edits by their status.
i have my model struct like the below :
type Detail struct {
Product
Stocks
}
type Product struct {
Name string `db:"name"`
Id int `db:"id"`
}
type Stocks {
Name string `db:"name"`
Price float `db:"price"`
Type string `db:"type"`
}
i would have a query to join the above tables like the below :
query, args, err := sqlx.In("select p.name , s.price from Product p,Stocks s where p.name=s.name and type IN (?)",typecodes)
query = s.Cmd.Db.Rebind(query)
var rows *sqlx.Rows
rows, err = s.Cmd.Db.Queryx(query, args...)
for rows.Next() {
var p model.Detail
err = rows.StructScan(&p)
}
Would like to know when i do rows.StructScan(&p) will the Product structure Name field be populated or will there be any ambuigity found for the same since Stocks also have a Name field ?
Currently i am not getting any result for the above.But when i comment the Name field in the Stocks struct, i am getting the data.
Let me know what i am missing here.
For ambiguous fields you're best annotating them with a prefix of their struct name, e.g. product_name, stock_name, then alias them appropriately in your SQL statement.
I.e.
type Detail struct {
Product
Stocks
}
type Product struct {
Name string `db:"product_name"`
Id int `db:"id"`
}
type Stocks {
Name string `db:"stock_name"`
Price float `db:"price"`
Type string `db:"type"`
}
And in your SQL:
SELECT p.name AS product_name, s.name AS stock_name, ... FROM Product p, Stocks s WHERE ...
I am trying to define one to many relation with gorm ORM . I have read all the docs over and over again . Could not find a way to do it.
func GetUser1(c *gin.Context) {
var user models.User
var activities models.UserActivity
query := DB.Debug().Find(&user, 1).Model(&user).Related(&activities).Error
if query != nil {
panic(query)
}
c.JSON(200, &user)
}
My Models are ..
type User struct {
Id int64
Username string
Password string `json:"-"`
Email string `json:",omitempty"`
UserActivities []UserActivity
}
type UserActivity struct {
Id int64
UserId int64 `json:"-"`
ActorId int64
CreatedAt time.Time
}
Debug Results are
[2015-11-21 22:21:54] [3.17ms] SELECT * FROM `users` WHERE (`id` = '1')
[2015-11-21 22:21:54] [1.39ms] SELECT * FROM `user_activities` WHERE (`user_id` = '1')
But I am getting null results
{
"Id": 1,
"Username": "test1",
"Email": "test1#friesen.com",
"UserActivities": null
}
All the primary keys and Indexes are right . I have also tried puttin gorm:"primary_key" and sql:"index" in UserActivities no luck so far .
However if I replace UserActivities []UserActivity with UserActivities UserActivity then i get only one row which seems to be right but why UserActivities []UserActivity giving no results
use gorm built in model gorm.Model so that your not messing up the "ID" constant
The solution to your problem is very simple.
Rather than querying
var user models.User
var activities models.UserActivity
query := DB.Debug().Find(&user, 1).Model(&user).Related(&activities).Error
just query
var user models.User
query := DB.Debug().Find(&user, 1).Model(&user).Related(&user.UserActivities).Error