gorm/callbacks/query.go

335 lines
11 KiB
Go

package callbacks
import (
"fmt"
"reflect"
"sort"
"strings"
"gorm.io/gorm"
"gorm.io/gorm/clause"
"gorm.io/gorm/schema"
"gorm.io/gorm/utils"
)
func Query(db *gorm.DB) {
if db.Error == nil {
BuildQuerySQL(db)
if !db.DryRun && db.Error == nil {
rows, err := db.Statement.ConnPool.QueryContext(db.Statement.Context, db.Statement.SQL.String(), db.Statement.Vars...)
if err != nil {
db.AddError(err)
return
}
defer func() {
db.AddError(rows.Close())
}()
gorm.Scan(rows, db, 0)
}
}
}
func BuildQuerySQL(db *gorm.DB) {
if db.Statement.Schema != nil {
for _, c := range db.Statement.Schema.QueryClauses {
db.Statement.AddClause(c)
}
}
if db.Statement.SQL.Len() == 0 {
db.Statement.SQL.Grow(100)
clauseSelect := clause.Select{Distinct: db.Statement.Distinct}
if db.Statement.ReflectValue.Kind() == reflect.Struct && db.Statement.ReflectValue.Type() == db.Statement.Schema.ModelType {
var conds []clause.Expression
for _, primaryField := range db.Statement.Schema.PrimaryFields {
if v, isZero := primaryField.ValueOf(db.Statement.Context, db.Statement.ReflectValue); !isZero {
conds = append(conds, clause.Eq{Column: clause.Column{Table: db.Statement.Table, Name: primaryField.DBName}, Value: v})
}
}
if len(conds) > 0 {
db.Statement.AddClause(clause.Where{Exprs: conds})
}
}
if len(db.Statement.Selects) > 0 {
clauseSelect.Columns = make([]clause.Column, len(db.Statement.Selects))
for idx, name := range db.Statement.Selects {
if db.Statement.Schema == nil {
clauseSelect.Columns[idx] = clause.Column{Name: name, Raw: true}
} else if f := db.Statement.Schema.LookUpField(name); f != nil {
clauseSelect.Columns[idx] = clause.Column{Name: f.DBName}
} else {
clauseSelect.Columns[idx] = clause.Column{Name: name, Raw: true}
}
}
} else if db.Statement.Schema != nil && len(db.Statement.Omits) > 0 {
selectColumns, _ := db.Statement.SelectAndOmitColumns(false, false)
clauseSelect.Columns = make([]clause.Column, 0, len(db.Statement.Schema.DBNames))
for _, dbName := range db.Statement.Schema.DBNames {
if v, ok := selectColumns[dbName]; (ok && v) || !ok {
clauseSelect.Columns = append(clauseSelect.Columns, clause.Column{Table: db.Statement.Table, Name: dbName})
}
}
} else if db.Statement.Schema != nil && db.Statement.ReflectValue.IsValid() {
queryFields := db.QueryFields
if !queryFields {
switch db.Statement.ReflectValue.Kind() {
case reflect.Struct:
queryFields = db.Statement.ReflectValue.Type() != db.Statement.Schema.ModelType
case reflect.Slice:
queryFields = db.Statement.ReflectValue.Type().Elem() != db.Statement.Schema.ModelType
}
}
if queryFields {
stmt := gorm.Statement{DB: db}
// smaller struct
if err := stmt.Parse(db.Statement.Dest); err == nil && (db.QueryFields || stmt.Schema.ModelType != db.Statement.Schema.ModelType) {
clauseSelect.Columns = make([]clause.Column, len(stmt.Schema.DBNames))
for idx, dbName := range stmt.Schema.DBNames {
clauseSelect.Columns[idx] = clause.Column{Table: db.Statement.Table, Name: dbName}
}
}
}
}
// inline joins
fromClause := clause.From{}
if v, ok := db.Statement.Clauses["FROM"].Expression.(clause.From); ok {
fromClause = v
}
if len(db.Statement.Joins) != 0 || len(fromClause.Joins) != 0 {
if len(db.Statement.Selects) == 0 && len(db.Statement.Omits) == 0 && db.Statement.Schema != nil {
clauseSelect.Columns = make([]clause.Column, len(db.Statement.Schema.DBNames))
for idx, dbName := range db.Statement.Schema.DBNames {
clauseSelect.Columns[idx] = clause.Column{Table: db.Statement.Table, Name: dbName}
}
}
specifiedRelationsName := make(map[string]interface{})
for _, join := range db.Statement.Joins {
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,
Selects: join.Selects, Omits: join.Omits,
}
selectColumns, restricted := columnStmt.SelectAndOmitColumns(false, false)
for _, s := range relation.FieldSchema.DBNames {
if v, ok := selectColumns[s]; (ok && v) || (!ok && !restricted) {
clauseSelect.Columns = append(clauseSelect.Columns, clause.Column{
Table: tableAliasName,
Name: s,
Alias: utils.NestedRelationName(tableAliasName, s),
})
}
}
exprs := make([]clause.Expression, len(relation.References))
for idx, ref := range relation.References {
if ref.OwnPrimaryKey {
exprs[idx] = clause.Eq{
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: parentTableName, Name: ref.ForeignKey.DBName},
Value: clause.Column{Table: tableAliasName, Name: ref.PrimaryKey.DBName},
}
} else {
exprs[idx] = clause.Eq{
Column: clause.Column{Table: tableAliasName, Name: ref.ForeignKey.DBName},
Value: ref.PrimaryValue,
}
}
}
}
{
onStmt := gorm.Statement{Table: tableAliasName, DB: db, Clauses: map[string]clause.Clause{}}
for _, c := range relation.FieldSchema.QueryClauses {
onStmt.AddClause(c)
}
if join.On != nil {
onStmt.AddClause(join.On)
}
if cs, ok := onStmt.Clauses["WHERE"]; ok {
if where, ok := cs.Expression.(clause.Where); ok {
where.Build(&onStmt)
if onSQL := onStmt.SQL.String(); onSQL != "" {
vars := onStmt.Vars
for idx, v := range vars {
bindvar := strings.Builder{}
onStmt.Vars = vars[0 : idx+1]
db.Dialector.BindVarTo(&bindvar, &onStmt, v)
onSQL = strings.Replace(onSQL, bindvar.String(), "?", 1)
}
exprs = append(exprs, clause.Expr{SQL: onSQL, Vars: vars})
}
}
}
}
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},
})
}
}
db.Statement.AddClause(fromClause)
db.Statement.Joins = nil
} else {
db.Statement.AddClauseIfNotExists(clause.From{})
}
db.Statement.AddClauseIfNotExists(clauseSelect)
db.Statement.Build(db.Statement.BuildClauses...)
}
}
func Preload(db *gorm.DB) {
if db.Error == nil && len(db.Statement.Preloads) > 0 {
if db.Statement.Schema == nil {
db.AddError(fmt.Errorf("%w when using preload", gorm.ErrModelValueRequired))
return
}
preloadMap := map[string]map[string][]interface{}{}
for name := range db.Statement.Preloads {
preloadFields := strings.Split(name, ".")
if preloadFields[0] == clause.Associations {
for _, rel := range db.Statement.Schema.Relationships.Relations {
if rel.Schema == db.Statement.Schema {
if _, ok := preloadMap[rel.Name]; !ok {
preloadMap[rel.Name] = map[string][]interface{}{}
}
if value := strings.TrimPrefix(strings.TrimPrefix(name, preloadFields[0]), "."); value != "" {
preloadMap[rel.Name][value] = db.Statement.Preloads[name]
}
}
}
} else {
if _, ok := preloadMap[preloadFields[0]]; !ok {
preloadMap[preloadFields[0]] = map[string][]interface{}{}
}
if value := strings.TrimPrefix(strings.TrimPrefix(name, preloadFields[0]), "."); value != "" {
preloadMap[preloadFields[0]][value] = db.Statement.Preloads[name]
}
}
}
preloadNames := make([]string, 0, len(preloadMap))
for key := range preloadMap {
preloadNames = append(preloadNames, key)
}
sort.Strings(preloadNames)
preloadDB := db.Session(&gorm.Session{Context: db.Statement.Context, NewDB: true, SkipHooks: db.Statement.SkipHooks, Initialized: true})
db.Statement.Settings.Range(func(k, v interface{}) bool {
preloadDB.Statement.Settings.Store(k, v)
return true
})
if err := preloadDB.Statement.Parse(db.Statement.Dest); err != nil {
return
}
preloadDB.Statement.ReflectValue = db.Statement.ReflectValue
preloadDB.Statement.Unscoped = db.Statement.Unscoped
for _, name := range preloadNames {
if rel := preloadDB.Statement.Schema.Relationships.Relations[name]; rel != nil {
db.AddError(preload(preloadDB.Table("").Session(&gorm.Session{Context: db.Statement.Context, SkipHooks: db.Statement.SkipHooks}), rel, append(db.Statement.Preloads[name], db.Statement.Preloads[clause.Associations]...), preloadMap[name]))
} else {
db.AddError(fmt.Errorf("%s: %w for schema %s", name, gorm.ErrUnsupportedRelation, db.Statement.Schema.Name))
}
}
}
}
func AfterQuery(db *gorm.DB) {
if db.Error == nil && db.Statement.Schema != nil && !db.Statement.SkipHooks && db.Statement.Schema.AfterFind && db.RowsAffected > 0 {
callMethod(db, func(value interface{}, tx *gorm.DB) bool {
if i, ok := value.(AfterFindInterface); ok {
db.AddError(i.AfterFind(tx))
return true
}
return false
})
}
}