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package gorm
import (
"errors"
"fmt"
"reflect"
)
// Association Mode contains some helper methods to handle relationship things easily.
type Association struct {
Error error
scope *Scope
column string
field *Field
}
// Find find out all related associations
func (association *Association) Find(value interface{}) *Association {
association.scope.related(value, association.column)
return association.setErr(association.scope.db.Error)
}
// Append append new associations for many2many, has_many, replace current association for has_one, belongs_to
func (association *Association) Append(values ...interface{}) *Association {
if association.Error != nil {
return association
}
if relationship := association.field.Relationship; relationship.Kind == "has_one" {
return association.Replace(values...)
}
return association.saveAssociations(values...)
}
// Replace replace current associations with new one
func (association *Association) Replace(values ...interface{}) *Association {
if association.Error != nil {
return association
}
var (
relationship = association.field.Relationship
scope = association.scope
field = association.field.Field
newDB = scope.NewDB()
)
// Append new values
association.field.Set(reflect.Zero(association.field.Field.Type()))
association.saveAssociations(values...)
// Belongs To
if relationship.Kind == "belongs_to" {
// Set foreign key to be null when clearing value (length equals 0)
if len(values) == 0 {
// Set foreign key to be nil
var foreignKeyMap = map[string]interface{}{}
for _, foreignKey := range relationship.ForeignDBNames {
foreignKeyMap[foreignKey] = nil
}
association.setErr(newDB.Model(scope.Value).UpdateColumn(foreignKeyMap).Error)
}
} else {
// Polymorphic Relations
if relationship.PolymorphicDBName != "" {
newDB = newDB.Where(fmt.Sprintf("%v = ?", scope.Quote(relationship.PolymorphicDBName)), relationship.PolymorphicValue)
}
// Delete Relations except new created
if len(values) > 0 {
var associationForeignFieldNames, associationForeignDBNames []string
if relationship.Kind == "many_to_many" {
// if many to many relations, get association fields name from association foreign keys
associationScope := scope.New(reflect.New(field.Type()).Interface())
for idx, dbName := range relationship.AssociationForeignFieldNames {
if field, ok := associationScope.FieldByName(dbName); ok {
associationForeignFieldNames = append(associationForeignFieldNames, field.Name)
associationForeignDBNames = append(associationForeignDBNames, relationship.AssociationForeignDBNames[idx])
}
}
} else {
// If has one/many relations, use primary keys
for _, field := range scope.New(reflect.New(field.Type()).Interface()).PrimaryFields() {
associationForeignFieldNames = append(associationForeignFieldNames, field.Name)
associationForeignDBNames = append(associationForeignDBNames, field.DBName)
}
}
newPrimaryKeys := scope.getColumnAsArray(associationForeignFieldNames, field.Interface())
if len(newPrimaryKeys) > 0 {
sql := fmt.Sprintf("%v NOT IN (%v)", toQueryCondition(scope, associationForeignDBNames), toQueryMarks(newPrimaryKeys))
newDB = newDB.Where(sql, toQueryValues(newPrimaryKeys)...)
}
}
if relationship.Kind == "many_to_many" {
// if many to many relations, delete related relations from join table
var sourceForeignFieldNames []string
for _, dbName := range relationship.ForeignFieldNames {
if field, ok := scope.FieldByName(dbName); ok {
sourceForeignFieldNames = append(sourceForeignFieldNames, field.Name)
}
}
if sourcePrimaryKeys := scope.getColumnAsArray(sourceForeignFieldNames, scope.Value); len(sourcePrimaryKeys) > 0 {
newDB = newDB.Where(fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(sourcePrimaryKeys)), toQueryValues(sourcePrimaryKeys)...)
association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, newDB))
}
} else if relationship.Kind == "has_one" || relationship.Kind == "has_many" {
// has_one or has_many relations, set foreign key to be nil (TODO or delete them?)
var foreignKeyMap = map[string]interface{}{}
for idx, foreignKey := range relationship.ForeignDBNames {
foreignKeyMap[foreignKey] = nil
if field, ok := scope.FieldByName(relationship.AssociationForeignFieldNames[idx]); ok {
newDB = newDB.Where(fmt.Sprintf("%v = ?", scope.Quote(foreignKey)), field.Field.Interface())
}
}
fieldValue := reflect.New(association.field.Field.Type()).Interface()
association.setErr(newDB.Model(fieldValue).UpdateColumn(foreignKeyMap).Error)
}
}
return association
}
// Delete remove relationship between source & passed arguments, but won't delete those arguments
func (association *Association) Delete(values ...interface{}) *Association {
if association.Error != nil {
return association
}
var (
relationship = association.field.Relationship
scope = association.scope
field = association.field.Field
newDB = scope.NewDB()
)
if len(values) == 0 {
return association
}
var deletingResourcePrimaryFieldNames, deletingResourcePrimaryDBNames []string
for _, field := range scope.New(reflect.New(field.Type()).Interface()).PrimaryFields() {
deletingResourcePrimaryFieldNames = append(deletingResourcePrimaryFieldNames, field.Name)
deletingResourcePrimaryDBNames = append(deletingResourcePrimaryDBNames, field.DBName)
}
deletingPrimaryKeys := scope.getColumnAsArray(deletingResourcePrimaryFieldNames, values...)
if relationship.Kind == "many_to_many" {
// source value's foreign keys
for idx, foreignKey := range relationship.ForeignDBNames {
if field, ok := scope.FieldByName(relationship.ForeignFieldNames[idx]); ok {
newDB = newDB.Where(fmt.Sprintf("%v = ?", scope.Quote(foreignKey)), field.Field.Interface())
}
}
// get association's foreign fields name
var associationScope = scope.New(reflect.New(field.Type()).Interface())
var associationForeignFieldNames []string
for _, associationDBName := range relationship.AssociationForeignFieldNames {
if field, ok := associationScope.FieldByName(associationDBName); ok {
associationForeignFieldNames = append(associationForeignFieldNames, field.Name)
}
}
// association value's foreign keys
deletingPrimaryKeys := scope.getColumnAsArray(associationForeignFieldNames, values...)
sql := fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.AssociationForeignDBNames), toQueryMarks(deletingPrimaryKeys))
newDB = newDB.Where(sql, toQueryValues(deletingPrimaryKeys)...)
association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, newDB))
} else {
var foreignKeyMap = map[string]interface{}{}
for _, foreignKey := range relationship.ForeignDBNames {
foreignKeyMap[foreignKey] = nil
}
if relationship.Kind == "belongs_to" {
// find with deleting relation's foreign keys
primaryKeys := scope.getColumnAsArray(relationship.AssociationForeignFieldNames, values...)
newDB = newDB.Where(
fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(primaryKeys)),
toQueryValues(primaryKeys)...,
)
// set foreign key to be null if there are some records affected
modelValue := reflect.New(scope.GetModelStruct().ModelType).Interface()
if results := newDB.Model(modelValue).UpdateColumn(foreignKeyMap); results.Error == nil {
if results.RowsAffected > 0 {
scope.updatedAttrsWithValues(foreignKeyMap)
}
} else {
association.setErr(results.Error)
}
} else if relationship.Kind == "has_one" || relationship.Kind == "has_many" {
// find all relations
primaryKeys := scope.getColumnAsArray(relationship.AssociationForeignFieldNames, scope.Value)
newDB = newDB.Where(
fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(primaryKeys)),
toQueryValues(primaryKeys)...,
)
// only include those deleting relations
newDB = newDB.Where(
fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, deletingResourcePrimaryDBNames), toQueryMarks(deletingPrimaryKeys)),
toQueryValues(deletingPrimaryKeys)...,
)
// set matched relation's foreign key to be null
fieldValue := reflect.New(association.field.Field.Type()).Interface()
association.setErr(newDB.Model(fieldValue).UpdateColumn(foreignKeyMap).Error)
}
}
// Remove deleted records from source's field
if association.Error == nil {
if field.Kind() == reflect.Slice {
leftValues := reflect.Zero(field.Type())
for i := 0; i < field.Len(); i++ {
reflectValue := field.Index(i)
primaryKey := scope.getColumnAsArray(deletingResourcePrimaryFieldNames, reflectValue.Interface())[0]
var isDeleted = false
for _, pk := range deletingPrimaryKeys {
if equalAsString(primaryKey, pk) {
isDeleted = true
break
}
}
if !isDeleted {
leftValues = reflect.Append(leftValues, reflectValue)
}
}
association.field.Set(leftValues)
} else if field.Kind() == reflect.Struct {
primaryKey := scope.getColumnAsArray(deletingResourcePrimaryFieldNames, field.Interface())[0]
for _, pk := range deletingPrimaryKeys {
if equalAsString(primaryKey, pk) {
association.field.Set(reflect.Zero(field.Type()))
break
}
}
}
}
return association
}
// Clear remove relationship between source & current associations, won't delete those associations
func (association *Association) Clear() *Association {
return association.Replace()
}
// Count return the count of current associations
func (association *Association) Count() int {
var (
count = 0
relationship = association.field.Relationship
scope = association.scope
fieldValue = association.field.Field.Interface()
query = scope.DB()
)
if relationship.Kind == "many_to_many" {
query = relationship.JoinTableHandler.JoinWith(relationship.JoinTableHandler, query, scope.Value)
} else if relationship.Kind == "has_many" || relationship.Kind == "has_one" {
primaryKeys := scope.getColumnAsArray(relationship.AssociationForeignFieldNames, scope.Value)
query = query.Where(
fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(primaryKeys)),
toQueryValues(primaryKeys)...,
)
} else if relationship.Kind == "belongs_to" {
primaryKeys := scope.getColumnAsArray(relationship.ForeignFieldNames, scope.Value)
query = query.Where(
fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.AssociationForeignDBNames), toQueryMarks(primaryKeys)),
toQueryValues(primaryKeys)...,
)
}
if relationship.PolymorphicType != "" {
query = query.Where(
fmt.Sprintf("%v.%v = ?", scope.New(fieldValue).QuotedTableName(), scope.Quote(relationship.PolymorphicDBName)),
relationship.PolymorphicValue,
)
}
if err := query.Model(fieldValue).Count(&count).Error; err != nil {
association.Error = err
}
return count
}
// saveAssociations save passed values as associations
func (association *Association) saveAssociations(values ...interface{}) *Association {
var (
scope = association.scope
field = association.field
relationship = field.Relationship
)
saveAssociation := func(reflectValue reflect.Value) {
// value has to been pointer
if reflectValue.Kind() != reflect.Ptr {
reflectPtr := reflect.New(reflectValue.Type())
reflectPtr.Elem().Set(reflectValue)
reflectValue = reflectPtr
}
// value has to been saved for many2many
if relationship.Kind == "many_to_many" {
if scope.New(reflectValue.Interface()).PrimaryKeyZero() {
association.setErr(scope.NewDB().Save(reflectValue.Interface()).Error)
}
}
// Assign Fields
var fieldType = field.Field.Type()
var setFieldBackToValue, setSliceFieldBackToValue bool
if reflectValue.Type().AssignableTo(fieldType) {
field.Set(reflectValue)
} else if reflectValue.Type().Elem().AssignableTo(fieldType) {
// if field's type is struct, then need to set value back to argument after save
setFieldBackToValue = true
field.Set(reflectValue.Elem())
} else if fieldType.Kind() == reflect.Slice {
if reflectValue.Type().AssignableTo(fieldType.Elem()) {
field.Set(reflect.Append(field.Field, reflectValue))
} else if reflectValue.Type().Elem().AssignableTo(fieldType.Elem()) {
// if field's type is slice of struct, then need to set value back to argument after save
setSliceFieldBackToValue = true
field.Set(reflect.Append(field.Field, reflectValue.Elem()))
}
}
if relationship.Kind == "many_to_many" {
association.setErr(relationship.JoinTableHandler.Add(relationship.JoinTableHandler, scope.NewDB(), scope.Value, reflectValue.Interface()))
} else {
association.setErr(scope.NewDB().Select(field.Name).Save(scope.Value).Error)
if setFieldBackToValue {
reflectValue.Elem().Set(field.Field)
} else if setSliceFieldBackToValue {
reflectValue.Elem().Set(field.Field.Index(field.Field.Len() - 1))
}
}
}
for _, value := range values {
reflectValue := reflect.ValueOf(value)
indirectReflectValue := reflect.Indirect(reflectValue)
if indirectReflectValue.Kind() == reflect.Struct {
saveAssociation(reflectValue)
} else if indirectReflectValue.Kind() == reflect.Slice {
for i := 0; i < indirectReflectValue.Len(); i++ {
saveAssociation(indirectReflectValue.Index(i))
}
} else {
association.setErr(errors.New("invalid value type"))
}
}
return association
}
func (association *Association) setErr(err error) *Association {
if err != nil {
association.Error = err
}
return association
}