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feat: support nested join (#6067) 

* feat: support nested join

* fix: empty rel value
This commit is contained in:
Cr 2023-03-10 17:21:56 +08:00 committed by GitHub
parent 654b5f2006
commit 8bf1f269cf
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5 changed files with 255 additions and 89 deletions
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72
callbacks/query.go
View File

@ -8,6 +8,8 @@ import (
"gorm.io/gorm"
"gorm.io/gorm/clause"
"gorm.io/gorm/schema"
"gorm.io/gorm/utils"
)
func Query(db *gorm.DB) {
@ -109,13 +111,46 @@ func BuildQuerySQL(db *gorm.DB) {
}
}
specifiedRelationsName := make(map[string]interface{})
for _, join := range db.Statement.Joins {
if db.Statement.Schema == nil {
fromClause.Joins = append(fromClause.Joins, clause.Join{
Expression: clause.NamedExpr{SQL: join.Name, Vars: join.Conds},
})
} else if relation, ok := db.Statement.Schema.Relationships.Relations[join.Name]; ok {
if db.Statement.Schema != nil {
var isRelations bool // is relations or raw sql
var relations []*schema.Relationship
relation, ok := db.Statement.Schema.Relationships.Relations[join.Name]
if ok {
isRelations = true
relations = append(relations, relation)
} else {
// handle nested join like "Manager.Company"
nestedJoinNames := strings.Split(join.Name, ".")
if len(nestedJoinNames) > 1 {
isNestedJoin := true
gussNestedRelations := make([]*schema.Relationship, 0, len(nestedJoinNames))
currentRelations := db.Statement.Schema.Relationships.Relations
for _, relname := range nestedJoinNames {
// incomplete match, only treated as raw sql
if relation, ok = currentRelations[relname]; ok {
gussNestedRelations = append(gussNestedRelations, relation)
currentRelations = relation.FieldSchema.Relationships.Relations
} else {
isNestedJoin = false
break
}
}
if isNestedJoin {
isRelations = true
relations = gussNestedRelations
}
}
}
if isRelations {
genJoinClause := func(joinType clause.JoinType, parentTableName string, relation *schema.Relationship) clause.Join {
tableAliasName := relation.Name
if parentTableName != clause.CurrentTable {
tableAliasName = utils.NestedRelationName(parentTableName, tableAliasName)
}
columnStmt := gorm.Statement{
Table: tableAliasName, DB: db, Schema: relation.FieldSchema,
@ -128,7 +163,7 @@ func BuildQuerySQL(db *gorm.DB) {
clauseSelect.Columns = append(clauseSelect.Columns, clause.Column{
Table: tableAliasName,
Name: s,
Alias: tableAliasName + "__" + s,
Alias: utils.NestedRelationName(tableAliasName, s),
})
}
}
@ -137,13 +172,13 @@ func BuildQuerySQL(db *gorm.DB) {
for idx, ref := range relation.References {
if ref.OwnPrimaryKey {
exprs[idx] = clause.Eq{
Column: clause.Column{Table: clause.CurrentTable, Name: ref.PrimaryKey.DBName},
Column: clause.Column{Table: parentTableName, Name: ref.PrimaryKey.DBName},
Value: clause.Column{Table: tableAliasName, Name: ref.ForeignKey.DBName},
}
} else {
if ref.PrimaryValue == "" {
exprs[idx] = clause.Eq{
Column: clause.Column{Table: clause.CurrentTable, Name: ref.ForeignKey.DBName},
Column: clause.Column{Table: parentTableName, Name: ref.ForeignKey.DBName},
Value: clause.Column{Table: tableAliasName, Name: ref.PrimaryKey.DBName},
}
} else {
@ -184,11 +219,28 @@ func BuildQuerySQL(db *gorm.DB) {
}
}
fromClause.Joins = append(fromClause.Joins, clause.Join{
Type: join.JoinType,
return clause.Join{
Type: joinType,
Table: clause.Table{Name: relation.FieldSchema.Table, Alias: tableAliasName},
ON: clause.Where{Exprs: exprs},
}
}
parentTableName := clause.CurrentTable
for _, rel := range relations {
// joins table alias like "Manager, Company, Manager__Company"
nestedAlias := utils.NestedRelationName(parentTableName, rel.Name)
if _, ok := specifiedRelationsName[nestedAlias]; !ok {
fromClause.Joins = append(fromClause.Joins, genJoinClause(join.JoinType, parentTableName, rel))
specifiedRelationsName[nestedAlias] = nil
}
parentTableName = rel.Name
}
} else {
fromClause.Joins = append(fromClause.Joins, clause.Join{
Expression: clause.NamedExpr{SQL: join.Name, Vars: join.Conds},
})
}
} else {
fromClause.Joins = append(fromClause.Joins, clause.Join{
Expression: clause.NamedExpr{SQL: join.Name, Vars: join.Conds},

60
scan.go
View File

@ -4,10 +4,10 @@ import (
"database/sql"
"database/sql/driver"
"reflect"
"strings"
"time"
"gorm.io/gorm/schema"
"gorm.io/gorm/utils"
)
// prepareValues prepare values slice
@ -50,7 +50,7 @@ func scanIntoMap(mapValue map[string]interface{}, values []interface{}, columns
}
}
func (db *DB) scanIntoStruct(rows Rows, reflectValue reflect.Value, values []interface{}, fields []*schema.Field, joinFields [][2]*schema.Field) {
func (db *DB) scanIntoStruct(rows Rows, reflectValue reflect.Value, values []interface{}, fields []*schema.Field, joinFields [][]*schema.Field) {
for idx, field := range fields {
if field != nil {
values[idx] = field.NewValuePool.Get()
@ -65,28 +65,45 @@ func (db *DB) scanIntoStruct(rows Rows, reflectValue reflect.Value, values []int
db.RowsAffected++
db.AddError(rows.Scan(values...))
joinedSchemaMap := make(map[*schema.Field]interface{})
joinedNestedSchemaMap := make(map[string]interface{})
for idx, field := range fields {
if field == nil {
continue
}
if len(joinFields) == 0 || joinFields[idx][0] == nil {
if len(joinFields) == 0 || len(joinFields[idx]) == 0 {
db.AddError(field.Set(db.Statement.Context, reflectValue, values[idx]))
} else {
joinSchema := joinFields[idx][0]
relValue := joinSchema.ReflectValueOf(db.Statement.Context, reflectValue)
} else { // joinFields count is larger than 2 when using join
var isNilPtrValue bool
var relValue reflect.Value
// does not contain raw dbname
nestedJoinSchemas := joinFields[idx][:len(joinFields[idx])-1]
// current reflect value
currentReflectValue := reflectValue
fullRels := make([]string, 0, len(nestedJoinSchemas))
for _, joinSchema := range nestedJoinSchemas {
fullRels = append(fullRels, joinSchema.Name)
relValue = joinSchema.ReflectValueOf(db.Statement.Context, currentReflectValue)
if relValue.Kind() == reflect.Ptr {
if _, ok := joinedSchemaMap[joinSchema]; !ok {
fullRelsName := utils.JoinNestedRelationNames(fullRels)
// same nested structure
if _, ok := joinedNestedSchemaMap[fullRelsName]; !ok {
if value := reflect.ValueOf(values[idx]).Elem(); value.Kind() == reflect.Ptr && value.IsNil() {
continue
isNilPtrValue = true
break
}
relValue.Set(reflect.New(relValue.Type().Elem()))
joinedSchemaMap[joinSchema] = nil
joinedNestedSchemaMap[fullRelsName] = nil
}
}
db.AddError(joinFields[idx][1].Set(db.Statement.Context, relValue, values[idx]))
currentReflectValue = relValue
}
if !isNilPtrValue { // ignore if value is nil
f := joinFields[idx][len(joinFields[idx])-1]
db.AddError(f.Set(db.Statement.Context, relValue, values[idx]))
}
}
// release data to pool
@ -163,7 +180,7 @@ func Scan(rows Rows, db *DB, mode ScanMode) {
default:
var (
fields = make([]*schema.Field, len(columns))
joinFields [][2]*schema.Field
joinFields [][]*schema.Field
sch = db.Statement.Schema
reflectValue = db.Statement.ReflectValue
)
@ -217,15 +234,26 @@ func Scan(rows Rows, db *DB, mode ScanMode) {
} else {
matchedFieldCount[column] = 1
}
} else if names := strings.Split(column, "__"); len(names) > 1 {
} else if names := utils.SplitNestedRelationName(column); len(names) > 1 { // has nested relation
if rel, ok := sch.Relationships.Relations[names[0]]; ok {
if field := rel.FieldSchema.LookUpField(strings.Join(names[1:], "__")); field != nil && field.Readable {
subNameCount := len(names)
// nested relation fields
relFields := make([]*schema.Field, 0, subNameCount-1)
relFields = append(relFields, rel.Field)
for _, name := range names[1 : subNameCount-1] {
rel = rel.FieldSchema.Relationships.Relations[name]
relFields = append(relFields, rel.Field)
}
// lastest name is raw dbname
dbName := names[subNameCount-1]
if field := rel.FieldSchema.LookUpField(dbName); field != nil && field.Readable {
fields[idx] = field
if len(joinFields) == 0 {
joinFields = make([][2]*schema.Field, len(columns))
joinFields = make([][]*schema.Field, len(columns))
}
joinFields[idx] = [2]*schema.Field{rel.Field, field}
relFields = append(relFields, field)
joinFields[idx] = relFields
continue
}
}

63
tests/joins_test.go
View File

@ -325,3 +325,66 @@ func TestJoinArgsWithDB(t *testing.T) {
}
AssertEqual(t, user4.NamedPet.Name, "")
}
func TestNestedJoins(t *testing.T) {
users := []User{
{
Name: "nested-joins-1",
Manager: GetUser("nested-joins-manager-1", Config{Company: true, NamedPet: true}),
NamedPet: &Pet{Name: "nested-joins-namepet-1", Toy: Toy{Name: "nested-joins-namepet-toy-1"}},
},
{
Name: "nested-joins-2",
Manager: GetUser("nested-joins-manager-2", Config{Company: true, NamedPet: true}),
NamedPet: &Pet{Name: "nested-joins-namepet-2", Toy: Toy{Name: "nested-joins-namepet-toy-2"}},
},
}
DB.Create(&users)
var userIDs []uint
for _, user := range users {
userIDs = append(userIDs, user.ID)
}
var users2 []User
if err := DB.
Joins("Manager").
Joins("Manager.Company").
Joins("Manager.NamedPet").
Joins("NamedPet").
Joins("NamedPet.Toy").
Find(&users2, "users.id IN ?", userIDs).Error; err != nil {
t.Fatalf("Failed to load with joins, got error: %v", err)
} else if len(users2) != len(users) {
t.Fatalf("Failed to load join users, got: %v, expect: %v", len(users2), len(users))
}
sort.Slice(users2, func(i, j int) bool {
return users2[i].ID > users2[j].ID
})
sort.Slice(users, func(i, j int) bool {
return users[i].ID > users[j].ID
})
for idx, user := range users {
// user
CheckUser(t, user, users2[idx])
if users2[idx].Manager == nil {
t.Fatalf("Failed to load Manager")
}
// manager
CheckUser(t, *user.Manager, *users2[idx].Manager)
// user pet
if users2[idx].NamedPet == nil {
t.Fatalf("Failed to load NamedPet")
}
CheckPet(t, *user.NamedPet, *users2[idx].NamedPet)
// manager pet
if users2[idx].Manager.NamedPet == nil {
t.Fatalf("Failed to load NamedPet")
}
CheckPet(t, *user.Manager.NamedPet, *users2[idx].Manager.NamedPet)
}
}

10
utils/tests/utils.go
View File

@ -13,8 +13,14 @@ import (
func AssertObjEqual(t *testing.T, r, e interface{}, names ...string) {
for _, name := range names {
got := reflect.Indirect(reflect.ValueOf(r)).FieldByName(name).Interface()
expect := reflect.Indirect(reflect.ValueOf(e)).FieldByName(name).Interface()
rv := reflect.Indirect(reflect.ValueOf(r))
ev := reflect.Indirect(reflect.ValueOf(e))
if rv.IsValid() != ev.IsValid() {
t.Errorf("%v: expect: %+v, got %+v", utils.FileWithLineNum(), r, e)
return
}
got := rv.FieldByName(name).Interface()
expect := ev.FieldByName(name).Interface()
t.Run(name, func(t *testing.T) {
AssertEqual(t, got, expect)
})

17
utils/utils.go
View File

@ -131,3 +131,20 @@ func ToString(value interface{}) string {
}
return ""
}
const nestedRelationSplit = "__"
// NestedRelationName nested relationships like `Manager__Company`
func NestedRelationName(prefix, name string) string {
return prefix + nestedRelationSplit + name
}
// SplitNestedRelationName Split nested relationships to `[]string{"Manager","Company"}`
func SplitNestedRelationName(name string) []string {
return strings.Split(name, nestedRelationSplit)
}
// JoinNestedRelationNames nested relationships like `Manager__Company`
func JoinNestedRelationNames(relationNames []string) string {
return strings.Join(relationNames, nestedRelationSplit)
}