gorm/schema/relationship.go

508 lines
15 KiB
Go

package schema
import (
"fmt"
"reflect"
"regexp"
"strings"
"github.com/jinzhu/inflection"
"gorm.io/gorm/clause"
)
// RelationshipType relationship type
type RelationshipType string
const (
HasOne RelationshipType = "has_one" // HasOneRel has one relationship
HasMany RelationshipType = "has_many" // HasManyRel has many relationship
BelongsTo RelationshipType = "belongs_to" // BelongsToRel belongs to relationship
Many2Many RelationshipType = "many_to_many" // Many2ManyRel many to many relationship
)
type Relationships struct {
HasOne []*Relationship
BelongsTo []*Relationship
HasMany []*Relationship
Many2Many []*Relationship
Relations map[string]*Relationship
}
type Relationship struct {
Name string
Type RelationshipType
Field *Field
Polymorphic *Polymorphic
References []*Reference
Schema *Schema
FieldSchema *Schema
JoinTable *Schema
foreignKeys, primaryKeys []string
}
type Polymorphic struct {
PolymorphicID *Field
PolymorphicType *Field
Value string
}
type Reference struct {
PrimaryKey *Field
PrimaryValue string
ForeignKey *Field
OwnPrimaryKey bool
}
func (schema *Schema) parseRelation(field *Field) {
var (
err error
fieldValue = reflect.New(field.IndirectFieldType).Interface()
relation = &Relationship{
Name: field.Name,
Field: field,
Schema: schema,
foreignKeys: toColumns(field.TagSettings["FOREIGNKEY"]),
primaryKeys: toColumns(field.TagSettings["REFERENCES"]),
}
)
if relation.FieldSchema, err = Parse(fieldValue, schema.cacheStore, schema.namer); err != nil {
schema.err = err
return
}
if polymorphic, _ := field.TagSettings["POLYMORPHIC"]; polymorphic != "" {
schema.buildPolymorphicRelation(relation, field, polymorphic)
} else if many2many, _ := field.TagSettings["MANY2MANY"]; many2many != "" {
schema.buildMany2ManyRelation(relation, field, many2many)
} else {
switch field.IndirectFieldType.Kind() {
case reflect.Struct, reflect.Slice:
schema.guessRelation(relation, field, true)
default:
schema.err = fmt.Errorf("unsupported data type %v for %v on field %v", relation.FieldSchema, schema, field.Name)
}
}
if relation.Type == "has" {
if relation.FieldSchema != relation.Schema && relation.Polymorphic == nil {
relation.FieldSchema.Relationships.Relations["_"+relation.Schema.Name+"_"+relation.Name] = relation
}
switch field.IndirectFieldType.Kind() {
case reflect.Struct:
relation.Type = HasOne
case reflect.Slice:
relation.Type = HasMany
}
}
if schema.err == nil {
schema.Relationships.Relations[relation.Name] = relation
switch relation.Type {
case HasOne:
schema.Relationships.HasOne = append(schema.Relationships.HasOne, relation)
case HasMany:
schema.Relationships.HasMany = append(schema.Relationships.HasMany, relation)
case BelongsTo:
schema.Relationships.BelongsTo = append(schema.Relationships.BelongsTo, relation)
case Many2Many:
schema.Relationships.Many2Many = append(schema.Relationships.Many2Many, relation)
}
}
}
// User has many Toys, its `Polymorphic` is `Owner`, Pet has one Toy, its `Polymorphic` is `Owner`
// type User struct {
// Toys []Toy `gorm:"polymorphic:Owner;"`
// }
// type Pet struct {
// Toy Toy `gorm:"polymorphic:Owner;"`
// }
// type Toy struct {
// OwnerID int
// OwnerType string
// }
func (schema *Schema) buildPolymorphicRelation(relation *Relationship, field *Field, polymorphic string) {
relation.Polymorphic = &Polymorphic{
Value: schema.Table,
PolymorphicType: relation.FieldSchema.FieldsByName[polymorphic+"Type"],
PolymorphicID: relation.FieldSchema.FieldsByName[polymorphic+"ID"],
}
if value, ok := field.TagSettings["POLYMORPHICVALUE"]; ok {
relation.Polymorphic.Value = strings.TrimSpace(value)
}
if relation.Polymorphic.PolymorphicType == nil {
schema.err = fmt.Errorf("invalid polymorphic type %v for %v on field %v, missing field %v", relation.FieldSchema, schema, field.Name, polymorphic+"Type")
}
if relation.Polymorphic.PolymorphicID == nil {
schema.err = fmt.Errorf("invalid polymorphic type %v for %v on field %v, missing field %v", relation.FieldSchema, schema, field.Name, polymorphic+"ID")
}
if schema.err == nil {
relation.References = append(relation.References, &Reference{
PrimaryValue: relation.Polymorphic.Value,
ForeignKey: relation.Polymorphic.PolymorphicType,
})
primaryKeyField := schema.PrioritizedPrimaryField
if len(relation.foreignKeys) > 0 {
if primaryKeyField = schema.LookUpField(relation.foreignKeys[0]); primaryKeyField == nil || len(relation.foreignKeys) > 1 {
schema.err = fmt.Errorf("invalid polymorphic foreign keys %+v for %v on field %v", relation.foreignKeys, schema, field.Name)
}
}
// use same data type for foreign keys
relation.Polymorphic.PolymorphicID.DataType = primaryKeyField.DataType
relation.References = append(relation.References, &Reference{
PrimaryKey: primaryKeyField,
ForeignKey: relation.Polymorphic.PolymorphicID,
OwnPrimaryKey: true,
})
}
relation.Type = "has"
}
func (schema *Schema) buildMany2ManyRelation(relation *Relationship, field *Field, many2many string) {
relation.Type = Many2Many
var (
err error
joinTableFields []reflect.StructField
fieldsMap = map[string]*Field{}
ownFieldsMap = map[string]bool{} // fix self join many2many
joinForeignKeys = toColumns(field.TagSettings["JOINFOREIGNKEY"])
joinReferences = toColumns(field.TagSettings["JOINREFERENCES"])
)
ownForeignFields := schema.PrimaryFields
refForeignFields := relation.FieldSchema.PrimaryFields
if len(relation.foreignKeys) > 0 {
ownForeignFields = []*Field{}
for _, foreignKey := range relation.foreignKeys {
if field := schema.LookUpField(foreignKey); field != nil {
ownForeignFields = append(ownForeignFields, field)
} else {
schema.err = fmt.Errorf("invalid foreign key: %v", foreignKey)
return
}
}
}
if len(relation.primaryKeys) > 0 {
refForeignFields = []*Field{}
for _, foreignKey := range relation.primaryKeys {
if field := relation.FieldSchema.LookUpField(foreignKey); field != nil {
refForeignFields = append(refForeignFields, field)
} else {
schema.err = fmt.Errorf("invalid foreign key: %v", foreignKey)
return
}
}
}
for idx, ownField := range ownForeignFields {
joinFieldName := schema.Name + ownField.Name
if len(joinForeignKeys) > idx {
joinFieldName = strings.Title(joinForeignKeys[idx])
}
ownFieldsMap[joinFieldName] = true
fieldsMap[joinFieldName] = ownField
joinTableFields = append(joinTableFields, reflect.StructField{
Name: joinFieldName,
PkgPath: ownField.StructField.PkgPath,
Type: ownField.StructField.Type,
Tag: removeSettingFromTag(ownField.StructField.Tag, "column"),
})
}
for idx, relField := range refForeignFields {
joinFieldName := relation.FieldSchema.Name + relField.Name
if len(joinReferences) > idx {
joinFieldName = strings.Title(joinReferences[idx])
}
if _, ok := ownFieldsMap[joinFieldName]; ok {
if field.Name != relation.FieldSchema.Name {
joinFieldName = inflection.Singular(field.Name) + relField.Name
} else {
joinFieldName += "Reference"
}
}
fieldsMap[joinFieldName] = relField
joinTableFields = append(joinTableFields, reflect.StructField{
Name: joinFieldName,
PkgPath: relField.StructField.PkgPath,
Type: relField.StructField.Type,
Tag: removeSettingFromTag(relField.StructField.Tag, "column"),
})
}
if relation.JoinTable, err = Parse(reflect.New(reflect.StructOf(joinTableFields)).Interface(), schema.cacheStore, schema.namer); err != nil {
schema.err = err
}
relation.JoinTable.Name = many2many
relation.JoinTable.Table = schema.namer.JoinTableName(many2many)
relation.JoinTable.PrimaryFields = make([]*Field, len(relation.JoinTable.Fields))
relName := relation.Schema.Name
relRefName := relation.FieldSchema.Name
if relName == relRefName {
relRefName = relation.Field.Name
}
if _, ok := relation.JoinTable.Relationships.Relations[relName]; !ok {
relation.JoinTable.Relationships.Relations[relName] = &Relationship{
Name: relName,
Type: BelongsTo,
Schema: relation.JoinTable,
FieldSchema: relation.Schema,
}
} else {
relation.JoinTable.Relationships.Relations[relName].References = []*Reference{}
}
if _, ok := relation.JoinTable.Relationships.Relations[relRefName]; !ok {
relation.JoinTable.Relationships.Relations[relRefName] = &Relationship{
Name: relRefName,
Type: BelongsTo,
Schema: relation.JoinTable,
FieldSchema: relation.FieldSchema,
}
} else {
relation.JoinTable.Relationships.Relations[relRefName].References = []*Reference{}
}
// build references
for idx, f := range relation.JoinTable.Fields {
// use same data type for foreign keys
f.DataType = fieldsMap[f.Name].DataType
relation.JoinTable.PrimaryFields[idx] = f
ownPriamryField := schema == fieldsMap[f.Name].Schema && ownFieldsMap[f.Name]
if ownPriamryField {
joinRel := relation.JoinTable.Relationships.Relations[relName]
joinRel.Field = relation.Field
joinRel.References = append(joinRel.References, &Reference{
PrimaryKey: fieldsMap[f.Name],
ForeignKey: f,
})
} else {
joinRefRel := relation.JoinTable.Relationships.Relations[relRefName]
if joinRefRel.Field == nil {
joinRefRel.Field = relation.Field
}
joinRefRel.References = append(joinRefRel.References, &Reference{
PrimaryKey: fieldsMap[f.Name],
ForeignKey: f,
})
}
relation.References = append(relation.References, &Reference{
PrimaryKey: fieldsMap[f.Name],
ForeignKey: f,
OwnPrimaryKey: ownPriamryField,
})
}
return
}
func (schema *Schema) guessRelation(relation *Relationship, field *Field, guessHas bool) {
var (
primaryFields, foreignFields []*Field
primarySchema, foreignSchema = schema, relation.FieldSchema
)
if !guessHas {
primarySchema, foreignSchema = relation.FieldSchema, schema
}
reguessOrErr := func(err string, args ...interface{}) {
if guessHas {
schema.guessRelation(relation, field, false)
} else {
schema.err = fmt.Errorf(err, args...)
}
}
if len(relation.foreignKeys) > 0 {
for _, foreignKey := range relation.foreignKeys {
if f := foreignSchema.LookUpField(foreignKey); f != nil {
foreignFields = append(foreignFields, f)
} else {
reguessOrErr("unsupported relations %v for %v on field %v with foreign keys %v", relation.FieldSchema, schema, field.Name, relation.foreignKeys)
return
}
}
} else {
for _, primaryField := range primarySchema.PrimaryFields {
lookUpName := schema.Name + primaryField.Name
if !guessHas {
lookUpName = field.Name + primaryField.Name
}
if f := foreignSchema.LookUpField(lookUpName); f != nil {
foreignFields = append(foreignFields, f)
primaryFields = append(primaryFields, primaryField)
}
}
}
if len(foreignFields) == 0 {
reguessOrErr("failed to guess %v's relations with %v's field %v 1 g %v", relation.FieldSchema, schema, field.Name, guessHas)
return
} else if len(relation.primaryKeys) > 0 {
for idx, primaryKey := range relation.primaryKeys {
if f := primarySchema.LookUpField(primaryKey); f != nil {
if len(primaryFields) < idx+1 {
primaryFields = append(primaryFields, f)
} else if f != primaryFields[idx] {
reguessOrErr("unsupported relations %v for %v on field %v with primary keys %v", relation.FieldSchema, schema, field.Name, relation.primaryKeys)
return
}
} else {
reguessOrErr("unsupported relations %v for %v on field %v with primary keys %v", relation.FieldSchema, schema, field.Name, relation.primaryKeys)
return
}
}
} else if len(primaryFields) == 0 {
if len(foreignFields) == 1 {
primaryFields = append(primaryFields, primarySchema.PrioritizedPrimaryField)
} else if len(primarySchema.PrimaryFields) == len(foreignFields) {
primaryFields = append(primaryFields, primarySchema.PrimaryFields...)
} else {
reguessOrErr("unsupported relations %v for %v on field %v", relation.FieldSchema, schema, field.Name)
return
}
}
// build references
for idx, foreignField := range foreignFields {
// use same data type for foreign keys
foreignField.DataType = primaryFields[idx].DataType
relation.References = append(relation.References, &Reference{
PrimaryKey: primaryFields[idx],
ForeignKey: foreignField,
OwnPrimaryKey: schema == primarySchema && guessHas,
})
}
if guessHas {
relation.Type = "has"
} else {
relation.Type = BelongsTo
}
}
type Constraint struct {
Name string
Field *Field
Schema *Schema
ForeignKeys []*Field
ReferenceSchema *Schema
References []*Field
OnDelete string
OnUpdate string
}
func (rel *Relationship) ParseConstraint() *Constraint {
str := rel.Field.TagSettings["CONSTRAINT"]
if str == "-" {
return nil
}
var (
name string
idx = strings.Index(str, ",")
settings = ParseTagSetting(str, ",")
)
if idx != -1 && regexp.MustCompile("^[A-Za-z-_]+$").MatchString(str[0:idx]) {
name = str[0:idx]
} else {
name = rel.Schema.namer.RelationshipFKName(*rel)
}
constraint := Constraint{
Name: name,
Field: rel.Field,
OnUpdate: settings["ONUPDATE"],
OnDelete: settings["ONDELETE"],
}
for _, ref := range rel.References {
if ref.PrimaryKey != nil {
constraint.ForeignKeys = append(constraint.ForeignKeys, ref.ForeignKey)
constraint.References = append(constraint.References, ref.PrimaryKey)
if ref.OwnPrimaryKey {
constraint.Schema = ref.ForeignKey.Schema
constraint.ReferenceSchema = rel.Schema
} else {
constraint.Schema = rel.Schema
constraint.ReferenceSchema = ref.PrimaryKey.Schema
}
}
}
if rel.JoinTable != nil {
return nil
}
return &constraint
}
func (rel *Relationship) ToQueryConditions(reflectValue reflect.Value) (conds []clause.Expression) {
foreignFields := []*Field{}
relForeignKeys := []string{}
if rel.JoinTable != nil {
for _, ref := range rel.References {
if ref.OwnPrimaryKey {
foreignFields = append(foreignFields, ref.PrimaryKey)
relForeignKeys = append(relForeignKeys, ref.ForeignKey.DBName)
} else if ref.PrimaryValue != "" {
conds = append(conds, clause.Eq{
Column: clause.Column{Table: rel.JoinTable.Table, Name: ref.ForeignKey.DBName},
Value: ref.PrimaryValue,
})
} else {
conds = append(conds, clause.Eq{
Column: clause.Column{Table: rel.JoinTable.Table, Name: ref.ForeignKey.DBName},
Value: clause.Column{Table: rel.FieldSchema.Table, Name: ref.PrimaryKey.DBName},
})
}
}
} else {
for _, ref := range rel.References {
if ref.OwnPrimaryKey {
relForeignKeys = append(relForeignKeys, ref.ForeignKey.DBName)
foreignFields = append(foreignFields, ref.PrimaryKey)
} else if ref.PrimaryValue != "" {
conds = append(conds, clause.Eq{
Column: clause.Column{Table: rel.FieldSchema.Table, Name: ref.ForeignKey.DBName},
Value: ref.PrimaryValue,
})
} else {
relForeignKeys = append(relForeignKeys, ref.PrimaryKey.DBName)
foreignFields = append(foreignFields, ref.ForeignKey)
}
}
}
_, foreignValues := GetIdentityFieldValuesMap(reflectValue, foreignFields)
column, values := ToQueryValues(relForeignKeys, foreignValues)
conds = append(conds, clause.IN{Column: column, Values: values})
return
}