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adjust code for preload
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daheige committed Nov 3, 2021
1 parent c170af1 commit e841ee0
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Showing 2 changed files with 96 additions and 88 deletions.
145 changes: 75 additions & 70 deletions callbacks/delete.go
Original file line number Diff line number Diff line change
Expand Up @@ -26,82 +26,87 @@ func BeforeDelete(db *gorm.DB) {
func DeleteBeforeAssociations(db *gorm.DB) {
if db.Error == nil && db.Statement.Schema != nil {
selectColumns, restricted := db.Statement.SelectAndOmitColumns(true, false)
if !restricted {
return
}

for column, v := range selectColumns {
if !v {
continue
}

rel, ok := db.Statement.Schema.Relationships.Relations[column]
if !ok {
continue
}

if restricted {
for column, v := range selectColumns {
if v {
if rel, ok := db.Statement.Schema.Relationships.Relations[column]; ok {
switch rel.Type {
case schema.HasOne, schema.HasMany:
queryConds := rel.ToQueryConditions(db.Statement.ReflectValue)
modelValue := reflect.New(rel.FieldSchema.ModelType).Interface()
tx := db.Session(&gorm.Session{NewDB: true}).Model(modelValue)
withoutConditions := false
if db.Statement.Unscoped {
tx = tx.Unscoped()
}

if len(db.Statement.Selects) > 0 {
selects := make([]string, 0, len(db.Statement.Selects))
for _, s := range db.Statement.Selects {
if s == clause.Associations {
selects = append(selects, s)
} else if strings.HasPrefix(s, column+".") {
selects = append(selects, strings.TrimPrefix(s, column+"."))
}
}

if len(selects) > 0 {
tx = tx.Select(selects)
}
}

for _, cond := range queryConds {
if c, ok := cond.(clause.IN); ok && len(c.Values) == 0 {
withoutConditions = true
break
}
}

if !withoutConditions {
if db.AddError(tx.Clauses(clause.Where{Exprs: queryConds}).Delete(modelValue).Error) != nil {
return
}
}
case schema.Many2Many:
var (
queryConds = make([]clause.Expression, 0, len(rel.References))
foreignFields = make([]*schema.Field, 0, len(rel.References))
relForeignKeys = make([]string, 0, len(rel.References))
modelValue = reflect.New(rel.JoinTable.ModelType).Interface()
table = rel.JoinTable.Table
tx = db.Session(&gorm.Session{NewDB: true}).Model(modelValue).Table(table)
)

for _, ref := range rel.References {
if ref.OwnPrimaryKey {
foreignFields = append(foreignFields, ref.PrimaryKey)
relForeignKeys = append(relForeignKeys, ref.ForeignKey.DBName)
} else if ref.PrimaryValue != "" {
queryConds = append(queryConds, clause.Eq{
Column: clause.Column{Table: rel.JoinTable.Table, Name: ref.ForeignKey.DBName},
Value: ref.PrimaryValue,
})
}
}

_, foreignValues := schema.GetIdentityFieldValuesMap(db.Statement.ReflectValue, foreignFields)
column, values := schema.ToQueryValues(table, relForeignKeys, foreignValues)
queryConds = append(queryConds, clause.IN{Column: column, Values: values})

if db.AddError(tx.Clauses(clause.Where{Exprs: queryConds}).Delete(modelValue).Error) != nil {
return
}
switch rel.Type {
case schema.HasOne, schema.HasMany:
queryConds := rel.ToQueryConditions(db.Statement.ReflectValue)
modelValue := reflect.New(rel.FieldSchema.ModelType).Interface()
tx := db.Session(&gorm.Session{NewDB: true}).Model(modelValue)
withoutConditions := false
if db.Statement.Unscoped {
tx = tx.Unscoped()
}

if len(db.Statement.Selects) > 0 {
selects := make([]string, 0, len(db.Statement.Selects))
for _, s := range db.Statement.Selects {
if s == clause.Associations {
selects = append(selects, s)
} else if columnPrefix := column + "."; strings.HasPrefix(s, columnPrefix) {
selects = append(selects, strings.TrimPrefix(s, columnPrefix))
}
}

if len(selects) > 0 {
tx = tx.Select(selects)
}
}

for _, cond := range queryConds {
if c, ok := cond.(clause.IN); ok && len(c.Values) == 0 {
withoutConditions = true
break
}
}

if !withoutConditions && db.AddError(tx.Clauses(clause.Where{Exprs: queryConds}).Delete(modelValue).Error) != nil {
return
}
case schema.Many2Many:
var (
queryConds = make([]clause.Expression, 0, len(rel.References))
foreignFields = make([]*schema.Field, 0, len(rel.References))
relForeignKeys = make([]string, 0, len(rel.References))
modelValue = reflect.New(rel.JoinTable.ModelType).Interface()
table = rel.JoinTable.Table
tx = db.Session(&gorm.Session{NewDB: true}).Model(modelValue).Table(table)
)

for _, ref := range rel.References {
if ref.OwnPrimaryKey {
foreignFields = append(foreignFields, ref.PrimaryKey)
relForeignKeys = append(relForeignKeys, ref.ForeignKey.DBName)
} else if ref.PrimaryValue != "" {
queryConds = append(queryConds, clause.Eq{
Column: clause.Column{Table: rel.JoinTable.Table, Name: ref.ForeignKey.DBName},
Value: ref.PrimaryValue,
})
}
}

_, foreignValues := schema.GetIdentityFieldValuesMap(db.Statement.ReflectValue, foreignFields)
column, values := schema.ToQueryValues(table, relForeignKeys, foreignValues)
queryConds = append(queryConds, clause.IN{Column: column, Values: values})

if db.AddError(tx.Clauses(clause.Where{Exprs: queryConds}).Delete(modelValue).Error) != nil {
return
}
}
}

}
}

Expand Down
39 changes: 21 additions & 18 deletions callbacks/preload.go
Original file line number Diff line number Diff line change
Expand Up @@ -145,27 +145,30 @@ func preload(db *gorm.DB, rel *schema.Relationship, conds []interface{}, preload
fieldValues[idx], _ = field.ValueOf(elem)
}

if datas, ok := identityMap[utils.ToStringKey(fieldValues...)]; ok {
for _, data := range datas {
reflectFieldValue := rel.Field.ReflectValueOf(data)
if reflectFieldValue.Kind() == reflect.Ptr && reflectFieldValue.IsNil() {
reflectFieldValue.Set(reflect.New(rel.Field.FieldType.Elem()))
}
datas, ok := identityMap[utils.ToStringKey(fieldValues...)]
if !ok {
db.AddError(fmt.Errorf("failed to assign association %#v, make sure foreign fields exists",
elem.Interface()))
continue
}

for _, data := range datas {
reflectFieldValue := rel.Field.ReflectValueOf(data)
if reflectFieldValue.Kind() == reflect.Ptr && reflectFieldValue.IsNil() {
reflectFieldValue.Set(reflect.New(rel.Field.FieldType.Elem()))
}

reflectFieldValue = reflect.Indirect(reflectFieldValue)
switch reflectFieldValue.Kind() {
case reflect.Struct:
rel.Field.Set(data, reflectResults.Index(i).Interface())
case reflect.Slice, reflect.Array:
if reflectFieldValue.Type().Elem().Kind() == reflect.Ptr {
rel.Field.Set(data, reflect.Append(reflectFieldValue, elem).Interface())
} else {
rel.Field.Set(data, reflect.Append(reflectFieldValue, elem.Elem()).Interface())
}
reflectFieldValue = reflect.Indirect(reflectFieldValue)
switch reflectFieldValue.Kind() {
case reflect.Struct:
rel.Field.Set(data, elem.Interface())
case reflect.Slice, reflect.Array:
if reflectFieldValue.Type().Elem().Kind() == reflect.Ptr {
rel.Field.Set(data, reflect.Append(reflectFieldValue, elem).Interface())
} else {
rel.Field.Set(data, reflect.Append(reflectFieldValue, elem.Elem()).Interface())
}
}
} else {
db.AddError(fmt.Errorf("failed to assign association %#v, make sure foreign fields exists", elem.Interface()))
}
}
}

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