gorm/association.go

501 lines
18 KiB
Go

package gorm
import (
"errors"
"fmt"
"reflect"
"strings"
"gorm.io/gorm/clause"
"gorm.io/gorm/schema"
"gorm.io/gorm/utils"
)
// Association Mode contains some helper methods to handle relationship things easily.
type Association struct {
DB *DB
Relationship *schema.Relationship
Error error
}
func (db *DB) Association(column string) *Association {
association := &Association{DB: db}
table := db.Statement.Table
if err := db.Statement.Parse(db.Statement.Model); err == nil {
db.Statement.Table = table
association.Relationship = db.Statement.Schema.Relationships.Relations[column]
if association.Relationship == nil {
association.Error = fmt.Errorf("%w: %v", ErrUnsupportedRelation, column)
}
db.Statement.ReflectValue = reflect.ValueOf(db.Statement.Model)
for db.Statement.ReflectValue.Kind() == reflect.Ptr {
db.Statement.ReflectValue = db.Statement.ReflectValue.Elem()
}
} else {
association.Error = err
}
return association
}
func (association *Association) Find(out interface{}, conds ...interface{}) error {
if association.Error == nil {
var (
queryConds = association.Relationship.ToQueryConditions(association.DB.Statement.ReflectValue)
tx = association.DB.Model(out)
)
if association.Relationship.JoinTable != nil {
if !tx.Statement.Unscoped && len(association.Relationship.JoinTable.QueryClauses) > 0 {
joinStmt := Statement{DB: tx, Schema: association.Relationship.JoinTable, Table: association.Relationship.JoinTable.Table, Clauses: map[string]clause.Clause{}}
for _, queryClause := range association.Relationship.JoinTable.QueryClauses {
joinStmt.AddClause(queryClause)
}
joinStmt.Build("WHERE")
tx.Clauses(clause.Expr{SQL: strings.Replace(joinStmt.SQL.String(), "WHERE ", "", 1), Vars: joinStmt.Vars})
}
tx.Clauses(clause.From{Joins: []clause.Join{{
Table: clause.Table{Name: association.Relationship.JoinTable.Table},
ON: clause.Where{Exprs: queryConds},
}}})
} else {
tx.Clauses(clause.Where{Exprs: queryConds})
}
association.Error = tx.Find(out, conds...).Error
}
return association.Error
}
func (association *Association) Append(values ...interface{}) error {
if association.Error == nil {
switch association.Relationship.Type {
case schema.HasOne, schema.BelongsTo:
if len(values) > 0 {
association.Error = association.Replace(values...)
}
default:
association.saveAssociation(false, values...)
}
}
return association.Error
}
func (association *Association) Replace(values ...interface{}) error {
if association.Error == nil {
// save associations
association.saveAssociation(true, values...)
// set old associations's foreign key to null
reflectValue := association.DB.Statement.ReflectValue
rel := association.Relationship
switch rel.Type {
case schema.BelongsTo:
if len(values) == 0 {
updateMap := map[string]interface{}{}
switch reflectValue.Kind() {
case reflect.Slice, reflect.Array:
for i := 0; i < reflectValue.Len(); i++ {
association.Error = rel.Field.Set(reflectValue.Index(i), reflect.Zero(rel.Field.FieldType).Interface())
}
case reflect.Struct:
association.Error = rel.Field.Set(reflectValue, reflect.Zero(rel.Field.FieldType).Interface())
}
for _, ref := range rel.References {
updateMap[ref.ForeignKey.DBName] = nil
}
association.Error = association.DB.UpdateColumns(updateMap).Error
}
case schema.HasOne, schema.HasMany:
var (
primaryFields []*schema.Field
foreignKeys []string
updateMap = map[string]interface{}{}
relValues = schema.GetRelationsValues(reflectValue, []*schema.Relationship{rel})
modelValue = reflect.New(rel.FieldSchema.ModelType).Interface()
tx = association.DB.Model(modelValue)
)
if _, rvs := schema.GetIdentityFieldValuesMap(relValues, rel.FieldSchema.PrimaryFields); len(rvs) > 0 {
if column, values := schema.ToQueryValues(rel.FieldSchema.Table, rel.FieldSchema.PrimaryFieldDBNames, rvs); len(values) > 0 {
tx.Not(clause.IN{Column: column, Values: values})
}
}
for _, ref := range rel.References {
if ref.OwnPrimaryKey {
primaryFields = append(primaryFields, ref.PrimaryKey)
foreignKeys = append(foreignKeys, ref.ForeignKey.DBName)
updateMap[ref.ForeignKey.DBName] = nil
} else if ref.PrimaryValue != "" {
tx.Where(clause.Eq{Column: ref.ForeignKey.DBName, Value: ref.PrimaryValue})
}
}
if _, pvs := schema.GetIdentityFieldValuesMap(reflectValue, primaryFields); len(pvs) > 0 {
column, values := schema.ToQueryValues(rel.FieldSchema.Table, foreignKeys, pvs)
tx.Where(clause.IN{Column: column, Values: values}).UpdateColumns(updateMap)
}
case schema.Many2Many:
var (
primaryFields, relPrimaryFields []*schema.Field
joinPrimaryKeys, joinRelPrimaryKeys []string
modelValue = reflect.New(rel.JoinTable.ModelType).Interface()
tx = association.DB.Model(modelValue)
)
for _, ref := range rel.References {
if ref.PrimaryValue == "" {
if ref.OwnPrimaryKey {
primaryFields = append(primaryFields, ref.PrimaryKey)
joinPrimaryKeys = append(joinPrimaryKeys, ref.ForeignKey.DBName)
} else {
relPrimaryFields = append(relPrimaryFields, ref.PrimaryKey)
joinRelPrimaryKeys = append(joinRelPrimaryKeys, ref.ForeignKey.DBName)
}
} else {
tx.Clauses(clause.Eq{Column: ref.ForeignKey.DBName, Value: ref.PrimaryValue})
}
}
_, pvs := schema.GetIdentityFieldValuesMap(reflectValue, primaryFields)
if column, values := schema.ToQueryValues(rel.JoinTable.Table, joinPrimaryKeys, pvs); len(values) > 0 {
tx.Where(clause.IN{Column: column, Values: values})
} else {
return ErrPrimaryKeyRequired
}
_, rvs := schema.GetIdentityFieldValuesMapFromValues(values, relPrimaryFields)
if relColumn, relValues := schema.ToQueryValues(rel.JoinTable.Table, joinRelPrimaryKeys, rvs); len(relValues) > 0 {
tx.Where(clause.Not(clause.IN{Column: relColumn, Values: relValues}))
}
tx.Delete(modelValue)
}
}
return association.Error
}
func (association *Association) Delete(values ...interface{}) error {
if association.Error == nil {
var (
reflectValue = association.DB.Statement.ReflectValue
rel = association.Relationship
primaryFields []*schema.Field
foreignKeys []string
updateAttrs = map[string]interface{}{}
conds []clause.Expression
)
for _, ref := range rel.References {
if ref.PrimaryValue == "" {
primaryFields = append(primaryFields, ref.PrimaryKey)
foreignKeys = append(foreignKeys, ref.ForeignKey.DBName)
updateAttrs[ref.ForeignKey.DBName] = nil
} else {
conds = append(conds, clause.Eq{Column: ref.ForeignKey.DBName, Value: ref.PrimaryValue})
}
}
switch rel.Type {
case schema.BelongsTo:
tx := association.DB.Model(reflect.New(rel.Schema.ModelType).Interface())
_, pvs := schema.GetIdentityFieldValuesMap(reflectValue, rel.Schema.PrimaryFields)
pcolumn, pvalues := schema.ToQueryValues(rel.Schema.Table, rel.Schema.PrimaryFieldDBNames, pvs)
conds = append(conds, clause.IN{Column: pcolumn, Values: pvalues})
_, rvs := schema.GetIdentityFieldValuesMapFromValues(values, primaryFields)
relColumn, relValues := schema.ToQueryValues(rel.Schema.Table, foreignKeys, rvs)
conds = append(conds, clause.IN{Column: relColumn, Values: relValues})
association.Error = tx.Clauses(conds...).UpdateColumns(updateAttrs).Error
case schema.HasOne, schema.HasMany:
tx := association.DB.Model(reflect.New(rel.FieldSchema.ModelType).Interface())
_, pvs := schema.GetIdentityFieldValuesMap(reflectValue, primaryFields)
pcolumn, pvalues := schema.ToQueryValues(rel.FieldSchema.Table, foreignKeys, pvs)
conds = append(conds, clause.IN{Column: pcolumn, Values: pvalues})
_, rvs := schema.GetIdentityFieldValuesMapFromValues(values, rel.FieldSchema.PrimaryFields)
relColumn, relValues := schema.ToQueryValues(rel.FieldSchema.Table, rel.FieldSchema.PrimaryFieldDBNames, rvs)
conds = append(conds, clause.IN{Column: relColumn, Values: relValues})
association.Error = tx.Clauses(conds...).UpdateColumns(updateAttrs).Error
case schema.Many2Many:
var (
primaryFields, relPrimaryFields []*schema.Field
joinPrimaryKeys, joinRelPrimaryKeys []string
modelValue = reflect.New(rel.JoinTable.ModelType).Interface()
)
for _, ref := range rel.References {
if ref.PrimaryValue == "" {
if ref.OwnPrimaryKey {
primaryFields = append(primaryFields, ref.PrimaryKey)
joinPrimaryKeys = append(joinPrimaryKeys, ref.ForeignKey.DBName)
} else {
relPrimaryFields = append(relPrimaryFields, ref.PrimaryKey)
joinRelPrimaryKeys = append(joinRelPrimaryKeys, ref.ForeignKey.DBName)
}
} else {
conds = append(conds, clause.Eq{Column: ref.ForeignKey.DBName, Value: ref.PrimaryValue})
}
}
_, pvs := schema.GetIdentityFieldValuesMap(reflectValue, primaryFields)
pcolumn, pvalues := schema.ToQueryValues(rel.JoinTable.Table, joinPrimaryKeys, pvs)
conds = append(conds, clause.IN{Column: pcolumn, Values: pvalues})
_, rvs := schema.GetIdentityFieldValuesMapFromValues(values, relPrimaryFields)
relColumn, relValues := schema.ToQueryValues(rel.JoinTable.Table, joinRelPrimaryKeys, rvs)
conds = append(conds, clause.IN{Column: relColumn, Values: relValues})
association.Error = association.DB.Where(clause.Where{Exprs: conds}).Model(nil).Delete(modelValue).Error
}
if association.Error == nil {
relValuesMap, _ := schema.GetIdentityFieldValuesMapFromValues(values, rel.FieldSchema.PrimaryFields)
cleanUpDeletedRelations := func(data reflect.Value) {
if _, zero := rel.Field.ValueOf(data); !zero {
fieldValue := reflect.Indirect(rel.Field.ReflectValueOf(data))
primaryValues := make([]interface{}, len(rel.FieldSchema.PrimaryFields))
switch fieldValue.Kind() {
case reflect.Slice, reflect.Array:
validFieldValues := reflect.Zero(rel.Field.IndirectFieldType)
for i := 0; i < fieldValue.Len(); i++ {
for idx, field := range rel.FieldSchema.PrimaryFields {
primaryValues[idx], _ = field.ValueOf(fieldValue.Index(i))
}
if _, ok := relValuesMap[utils.ToStringKey(primaryValues...)]; !ok {
validFieldValues = reflect.Append(validFieldValues, fieldValue.Index(i))
}
}
association.Error = rel.Field.Set(data, validFieldValues.Interface())
case reflect.Struct:
for idx, field := range rel.FieldSchema.PrimaryFields {
primaryValues[idx], _ = field.ValueOf(fieldValue)
}
if _, ok := relValuesMap[utils.ToStringKey(primaryValues...)]; ok {
if association.Error = rel.Field.Set(data, reflect.Zero(rel.FieldSchema.ModelType).Interface()); association.Error != nil {
break
}
if rel.JoinTable == nil {
for _, ref := range rel.References {
if ref.OwnPrimaryKey || ref.PrimaryValue != "" {
association.Error = ref.ForeignKey.Set(fieldValue, reflect.Zero(ref.ForeignKey.FieldType).Interface())
} else {
association.Error = ref.ForeignKey.Set(data, reflect.Zero(ref.ForeignKey.FieldType).Interface())
}
}
}
}
}
}
}
switch reflectValue.Kind() {
case reflect.Slice, reflect.Array:
for i := 0; i < reflectValue.Len(); i++ {
cleanUpDeletedRelations(reflect.Indirect(reflectValue.Index(i)))
}
case reflect.Struct:
cleanUpDeletedRelations(reflectValue)
}
}
}
return association.Error
}
func (association *Association) Clear() error {
return association.Replace()
}
func (association *Association) Count() (count int64) {
if association.Error == nil {
var (
conds = association.Relationship.ToQueryConditions(association.DB.Statement.ReflectValue)
modelValue = reflect.New(association.Relationship.FieldSchema.ModelType).Interface()
tx = association.DB.Model(modelValue)
)
if association.Relationship.JoinTable != nil {
if !tx.Statement.Unscoped && len(association.Relationship.JoinTable.QueryClauses) > 0 {
joinStmt := Statement{DB: tx, Schema: association.Relationship.JoinTable, Table: association.Relationship.JoinTable.Table, Clauses: map[string]clause.Clause{}}
for _, queryClause := range association.Relationship.JoinTable.QueryClauses {
joinStmt.AddClause(queryClause)
}
joinStmt.Build("WHERE", "LIMIT")
tx.Clauses(clause.Expr{SQL: strings.Replace(joinStmt.SQL.String(), "WHERE ", "", 1), Vars: joinStmt.Vars})
}
tx.Clauses(clause.From{Joins: []clause.Join{{
Table: clause.Table{Name: association.Relationship.JoinTable.Table},
ON: clause.Where{Exprs: conds},
}}})
} else {
tx.Clauses(clause.Where{Exprs: conds})
}
association.Error = tx.Count(&count).Error
}
return
}
type assignBack struct {
Source reflect.Value
Index int
Dest reflect.Value
}
func (association *Association) saveAssociation(clear bool, values ...interface{}) {
var (
reflectValue = association.DB.Statement.ReflectValue
assignBacks []assignBack // assign association values back to arguments after save
)
appendToRelations := func(source, rv reflect.Value, clear bool) {
switch association.Relationship.Type {
case schema.HasOne, schema.BelongsTo:
switch rv.Kind() {
case reflect.Slice, reflect.Array:
if rv.Len() > 0 {
association.Error = association.Relationship.Field.Set(source, rv.Index(0).Addr().Interface())
if association.Relationship.Field.FieldType.Kind() == reflect.Struct {
assignBacks = append(assignBacks, assignBack{Source: source, Dest: rv.Index(0)})
}
}
case reflect.Struct:
association.Error = association.Relationship.Field.Set(source, rv.Addr().Interface())
if association.Relationship.Field.FieldType.Kind() == reflect.Struct {
assignBacks = append(assignBacks, assignBack{Source: source, Dest: rv})
}
}
case schema.HasMany, schema.Many2Many:
elemType := association.Relationship.Field.IndirectFieldType.Elem()
fieldValue := reflect.Indirect(association.Relationship.Field.ReflectValueOf(source))
if clear {
fieldValue = reflect.New(association.Relationship.Field.IndirectFieldType).Elem()
}
appendToFieldValues := func(ev reflect.Value) {
if ev.Type().AssignableTo(elemType) {
fieldValue = reflect.Append(fieldValue, ev)
} else if ev.Type().Elem().AssignableTo(elemType) {
fieldValue = reflect.Append(fieldValue, ev.Elem())
} else {
association.Error = fmt.Errorf("unsupported data type: %v for relation %v", ev.Type(), association.Relationship.Name)
}
if elemType.Kind() == reflect.Struct {
assignBacks = append(assignBacks, assignBack{Source: source, Dest: ev, Index: fieldValue.Len()})
}
}
switch rv.Kind() {
case reflect.Slice, reflect.Array:
for i := 0; i < rv.Len(); i++ {
appendToFieldValues(reflect.Indirect(rv.Index(i)).Addr())
}
case reflect.Struct:
appendToFieldValues(rv.Addr())
}
if association.Error == nil {
association.Error = association.Relationship.Field.Set(source, fieldValue.Interface())
}
}
}
selectedSaveColumns := []string{association.Relationship.Name}
for _, ref := range association.Relationship.References {
if !ref.OwnPrimaryKey {
selectedSaveColumns = append(selectedSaveColumns, ref.ForeignKey.Name)
}
}
switch reflectValue.Kind() {
case reflect.Slice, reflect.Array:
if len(values) != reflectValue.Len() {
if clear && len(values) == 0 {
for i := 0; i < reflectValue.Len(); i++ {
if err := association.Relationship.Field.Set(reflectValue.Index(i), reflect.New(association.Relationship.Field.IndirectFieldType).Interface()); err != nil {
association.Error = err
break
}
if association.Relationship.JoinTable == nil {
for _, ref := range association.Relationship.References {
if !ref.OwnPrimaryKey && ref.PrimaryValue == "" {
if err := ref.ForeignKey.Set(reflectValue.Index(i), reflect.Zero(ref.ForeignKey.FieldType).Interface()); err != nil {
association.Error = err
break
}
}
}
}
}
break
}
association.Error = errors.New("invalid association values, length doesn't match")
return
}
for i := 0; i < reflectValue.Len(); i++ {
appendToRelations(reflectValue.Index(i), reflect.Indirect(reflect.ValueOf(values[i])), clear)
// TODO support save slice data, sql with case?
association.Error = association.DB.Session(&Session{}).Select(selectedSaveColumns).Model(nil).Save(reflectValue.Index(i).Addr().Interface()).Error
}
case reflect.Struct:
if clear && len(values) == 0 {
association.Error = association.Relationship.Field.Set(reflectValue, reflect.New(association.Relationship.Field.IndirectFieldType).Interface())
if association.Relationship.JoinTable == nil && association.Error == nil {
for _, ref := range association.Relationship.References {
if !ref.OwnPrimaryKey && ref.PrimaryValue == "" {
association.Error = ref.ForeignKey.Set(reflectValue, reflect.Zero(ref.ForeignKey.FieldType).Interface())
}
}
}
}
for idx, value := range values {
rv := reflect.Indirect(reflect.ValueOf(value))
appendToRelations(reflectValue, rv, clear && idx == 0)
}
if len(values) > 0 {
association.Error = association.DB.Session(&Session{}).Select(selectedSaveColumns).Model(nil).Save(reflectValue.Addr().Interface()).Error
}
}
for _, assignBack := range assignBacks {
fieldValue := reflect.Indirect(association.Relationship.Field.ReflectValueOf(assignBack.Source))
if assignBack.Index > 0 {
reflect.Indirect(assignBack.Dest).Set(fieldValue.Index(assignBack.Index - 1))
} else {
reflect.Indirect(assignBack.Dest).Set(fieldValue)
}
}
}