gorm/finisher_api.go

package gorm

import (
	"database/sql"
	"errors"
	"fmt"
	"reflect"
	"strings"

	"gorm.io/gorm/clause"
	"gorm.io/gorm/logger"
	"gorm.io/gorm/schema"
	"gorm.io/gorm/utils"
)

// Create insert the value into database
func (db *DB) Create(value interface{}) (tx *DB) {
	tx = db.getInstance()
	tx.Statement.Dest = value
	tx.callbacks.Create().Execute(tx)
	return
}

// Save update value in database, if the value doesn't have primary key, will insert it
func (db *DB) Save(value interface{}) (tx *DB) {
	tx = db.getInstance()
	tx.Statement.Dest = value

	reflectValue := reflect.Indirect(reflect.ValueOf(value))
	switch reflectValue.Kind() {
	case reflect.Slice, reflect.Array:
		tx.Statement.UpdatingColumn = true
		tx.callbacks.Create().Execute(tx)
	case reflect.Struct:
		if err := tx.Statement.Parse(value); err == nil && tx.Statement.Schema != nil {
			for _, pf := range tx.Statement.Schema.PrimaryFields {
				if _, isZero := pf.ValueOf(reflectValue); isZero {
					tx.callbacks.Create().Execute(tx)
					return
				}
			}
		}

		fallthrough
	default:
		selectedUpdate := len(tx.Statement.Selects) != 0
		// when updating, use all fields including those zero-value fields
		if !selectedUpdate {
			tx.Statement.Selects = append(tx.Statement.Selects, "*")
		}

		tx.callbacks.Update().Execute(tx)

		if tx.Error == nil && tx.RowsAffected == 0 && !tx.DryRun && !selectedUpdate {
			result := reflect.New(tx.Statement.Schema.ModelType).Interface()
			if err := tx.Session(&Session{WithConditions: true}).First(result).Error; errors.Is(err, ErrRecordNotFound) {
				return tx.Create(value)
			}
		}
	}

	return
}

// First find first record that match given conditions, order by primary key
func (db *DB) First(dest interface{}, conds ...interface{}) (tx *DB) {
	tx = db.Limit(1).Order(clause.OrderByColumn{
		Column: clause.Column{Table: clause.CurrentTable, Name: clause.PrimaryKey},
	})
	if len(conds) > 0 {
		tx.Statement.AddClause(clause.Where{Exprs: tx.Statement.BuildCondition(conds[0], conds[1:]...)})
	}
	tx.Statement.RaiseErrorOnNotFound = true
	tx.Statement.Dest = dest
	tx.callbacks.Query().Execute(tx)
	return
}

// Take return a record that match given conditions, the order will depend on the database implementation
func (db *DB) Take(dest interface{}, conds ...interface{}) (tx *DB) {
	tx = db.Limit(1)
	if len(conds) > 0 {
		tx.Statement.AddClause(clause.Where{Exprs: tx.Statement.BuildCondition(conds[0], conds[1:]...)})
	}
	tx.Statement.RaiseErrorOnNotFound = true
	tx.Statement.Dest = dest
	tx.callbacks.Query().Execute(tx)
	return
}

// Last find last record that match given conditions, order by primary key
func (db *DB) Last(dest interface{}, conds ...interface{}) (tx *DB) {
	tx = db.Limit(1).Order(clause.OrderByColumn{
		Column: clause.Column{Table: clause.CurrentTable, Name: clause.PrimaryKey},
		Desc:   true,
	})
	if len(conds) > 0 {
		tx.Statement.AddClause(clause.Where{Exprs: tx.Statement.BuildCondition(conds[0], conds[1:]...)})
	}
	tx.Statement.RaiseErrorOnNotFound = true
	tx.Statement.Dest = dest
	tx.callbacks.Query().Execute(tx)
	return
}

// Find find records that match given conditions
func (db *DB) Find(dest interface{}, conds ...interface{}) (tx *DB) {
	tx = db.getInstance()
	if len(conds) > 0 {
		tx.Statement.AddClause(clause.Where{Exprs: tx.Statement.BuildCondition(conds[0], conds[1:]...)})
	}
	tx.Statement.Dest = dest
	tx.callbacks.Query().Execute(tx)
	return
}

// FindInBatches find records in batches
func (db *DB) FindInBatches(dest interface{}, batchSize int, fc func(tx *DB, batch int) error) (tx *DB) {
	tx = db.Session(&Session{WithConditions: true})
	rowsAffected := int64(0)
	batch := 0

	for {
		result := tx.Limit(batchSize).Offset(batch * batchSize).Find(dest)
		rowsAffected += result.RowsAffected
		batch++

		if result.Error == nil && result.RowsAffected != 0 {
			tx.AddError(fc(result, batch))
		}

		if tx.Error != nil || int(result.RowsAffected) < batchSize {
			break
		}
	}

	tx.RowsAffected = rowsAffected
	return
}

func (tx *DB) assignInterfacesToValue(values ...interface{}) {
	for _, value := range values {
		switch v := value.(type) {
		case []clause.Expression:
			for _, expr := range v {
				if eq, ok := expr.(clause.Eq); ok {
					switch column := eq.Column.(type) {
					case string:
						if field := tx.Statement.Schema.LookUpField(column); field != nil {
							tx.AddError(field.Set(tx.Statement.ReflectValue, eq.Value))
						}
					case clause.Column:
						if field := tx.Statement.Schema.LookUpField(column.Name); field != nil {
							tx.AddError(field.Set(tx.Statement.ReflectValue, eq.Value))
						}
					}
				} else if andCond, ok := expr.(clause.AndConditions); ok {
					tx.assignInterfacesToValue(andCond.Exprs)
				}
			}
		case clause.Expression, map[string]string, map[interface{}]interface{}, map[string]interface{}:
			exprs := tx.Statement.BuildCondition(value)
			tx.assignInterfacesToValue(exprs)
		default:
			if s, err := schema.Parse(value, tx.cacheStore, tx.NamingStrategy); err == nil {
				reflectValue := reflect.Indirect(reflect.ValueOf(value))
				switch reflectValue.Kind() {
				case reflect.Struct:
					for _, f := range s.Fields {
						if f.Readable {
							if v, isZero := f.ValueOf(reflectValue); !isZero {
								if field := tx.Statement.Schema.LookUpField(f.Name); field != nil {
									tx.AddError(field.Set(tx.Statement.ReflectValue, v))
								}
							}
						}
					}
				}
			} else if len(values) > 0 {
				exprs := tx.Statement.BuildCondition(values[0], values[1:]...)
				tx.assignInterfacesToValue(exprs)
				return
			}
		}
	}
}

func (db *DB) FirstOrInit(dest interface{}, conds ...interface{}) (tx *DB) {
	if tx = db.First(dest, conds...); errors.Is(tx.Error, ErrRecordNotFound) {
		if c, ok := tx.Statement.Clauses["WHERE"]; ok {
			if where, ok := c.Expression.(clause.Where); ok {
				tx.assignInterfacesToValue(where.Exprs)
			}
		}

		// initialize with attrs, conds
		if len(tx.Statement.attrs) > 0 {
			tx.assignInterfacesToValue(tx.Statement.attrs...)
		}
		tx.Error = nil
	}

	// initialize with attrs, conds
	if len(tx.Statement.assigns) > 0 {
		tx.assignInterfacesToValue(tx.Statement.assigns...)
	}
	return
}

func (db *DB) FirstOrCreate(dest interface{}, conds ...interface{}) (tx *DB) {
	if tx = db.First(dest, conds...); errors.Is(tx.Error, ErrRecordNotFound) {
		tx.Error = nil

		if c, ok := tx.Statement.Clauses["WHERE"]; ok {
			if where, ok := c.Expression.(clause.Where); ok {
				tx.assignInterfacesToValue(where.Exprs)
			}
		}

		// initialize with attrs, conds
		if len(tx.Statement.attrs) > 0 {
			tx.assignInterfacesToValue(tx.Statement.attrs...)
		}

		// initialize with attrs, conds
		if len(tx.Statement.assigns) > 0 {
			tx.assignInterfacesToValue(tx.Statement.assigns...)
		}

		return tx.Create(dest)
	} else if len(db.Statement.assigns) > 0 {
		exprs := tx.Statement.BuildCondition(tx.Statement.assigns[0], tx.Statement.assigns[1:]...)
		assigns := map[string]interface{}{}
		for _, expr := range exprs {
			if eq, ok := expr.(clause.Eq); ok {
				switch column := eq.Column.(type) {
				case string:
					assigns[column] = eq.Value
				case clause.Column:
					assigns[column.Name] = eq.Value
				default:
				}
			}
		}

		return tx.Model(dest).Updates(assigns)
	}

	return db
}

// Update update attributes with callbacks, refer: https://gorm.io/docs/update.html#Update-Changed-Fields
func (db *DB) Update(column string, value interface{}) (tx *DB) {
	tx = db.getInstance()
	tx.Statement.Dest = map[string]interface{}{column: value}
	tx.callbacks.Update().Execute(tx)
	return
}

// Updates update attributes with callbacks, refer: https://gorm.io/docs/update.html#Update-Changed-Fields
func (db *DB) Updates(values interface{}) (tx *DB) {
	tx = db.getInstance()
	tx.Statement.Dest = values
	tx.callbacks.Update().Execute(tx)
	return
}

func (db *DB) UpdateColumn(column string, value interface{}) (tx *DB) {
	tx = db.getInstance()
	tx.Statement.Dest = map[string]interface{}{column: value}
	tx.Statement.UpdatingColumn = true
	tx.callbacks.Update().Execute(tx)
	return
}

func (db *DB) UpdateColumns(values interface{}) (tx *DB) {
	tx = db.getInstance()
	tx.Statement.Dest = values
	tx.Statement.UpdatingColumn = true
	tx.callbacks.Update().Execute(tx)
	return
}

// Delete delete value match given conditions, if the value has primary key, then will including the primary key as condition
func (db *DB) Delete(value interface{}, conds ...interface{}) (tx *DB) {
	tx = db.getInstance()
	if len(conds) > 0 {
		tx.Statement.AddClause(clause.Where{Exprs: tx.Statement.BuildCondition(conds[0], conds[1:]...)})
	}
	tx.Statement.Dest = value
	tx.callbacks.Delete().Execute(tx)
	return
}

func (db *DB) Count(count *int64) (tx *DB) {
	tx = db.getInstance()
	if tx.Statement.Model == nil {
		tx.Statement.Model = tx.Statement.Dest
		defer func() {
			tx.Statement.Model = nil
		}()
	}

	if len(tx.Statement.Selects) == 0 {
		tx.Statement.AddClause(clause.Select{Expression: clause.Expr{SQL: "count(1)"}})
		defer delete(tx.Statement.Clauses, "SELECT")
	} else if !strings.Contains(strings.ToLower(tx.Statement.Selects[0]), "count(") {
		expr := clause.Expr{SQL: "count(1)"}

		if len(tx.Statement.Selects) == 1 {
			dbName := tx.Statement.Selects[0]
			if tx.Statement.Parse(tx.Statement.Model) == nil {
				if f := tx.Statement.Schema.LookUpField(dbName); f != nil {
					dbName = f.DBName
				}
			}

			if tx.Statement.Distinct {
				expr = clause.Expr{SQL: "COUNT(DISTINCT(?))", Vars: []interface{}{clause.Column{Name: dbName}}}
			} else {
				expr = clause.Expr{SQL: "COUNT(?)", Vars: []interface{}{clause.Column{Name: dbName}}}
			}
		}

		tx.Statement.AddClause(clause.Select{Expression: expr})
		defer tx.Statement.AddClause(clause.Select{})
	}

	if orderByClause, ok := db.Statement.Clauses["ORDER BY"]; ok {
		if _, ok := db.Statement.