gorm/callbacks/delete.go

package callbacks

import (
	"reflect"

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

func BeforeDelete(db *gorm.DB) {
	if db.Error == nil && db.Statement.Schema != nil && db.Statement.Schema.BeforeDelete {
		callMethod(db, func(value interface{}, tx *gorm.DB) bool {
			if i, ok := value.(BeforeDeleteInterface); ok {
				db.AddError(i.BeforeDelete(tx))
				return true
			}

			return false
		})
	}
}

func Delete(db *gorm.DB) {
	if db.Error == nil {
		if db.Statement.Schema != nil && !db.Statement.Unscoped {
			for _, c := range db.Statement.Schema.DeleteClauses {
				db.Statement.AddClause(c)
			}
		}

		if db.Statement.SQL.String() == "" {
			db.Statement.SQL.Grow(100)
			db.Statement.AddClauseIfNotExists(clause.Delete{})

			if db.Statement.Schema != nil {
				_, queryValues := schema.GetIdentityFieldValuesMap(db.Statement.ReflectValue, db.Statement.Schema.PrimaryFields)
				column, values := schema.ToQueryValues(db.Statement.Table, db.Statement.Schema.PrimaryFieldDBNames, queryValues)

				if len(values) > 0 {
					db.Statement.AddClause(clause.Where{Exprs: []clause.Expression{clause.IN{Column: column, Values: values}}})
				}

				if db.Statement.ReflectValue.CanAddr() && db.Statement.Dest != db.Statement.Model && db.Statement.Model != nil {
					_, queryValues = schema.GetIdentityFieldValuesMap(reflect.ValueOf(db.Statement.Model), db.Statement.Schema.PrimaryFields)
					column, values = schema.ToQueryValues(db.Statement.Table, db.Statement.Schema.PrimaryFieldDBNames, queryValues)

					if len(values) > 0 {
						db.Statement.AddClause(clause.Where{Exprs: []clause.Expression{clause.IN{Column: column, Values: values}}})
					}
				}
			}

			db.Statement.AddClauseIfNotExists(clause.From{})
			db.Statement.Build("DELETE", "FROM", "WHERE")
		}

		if _, ok := db.Statement.Clauses["WHERE"]; !db.AllowGlobalUpdate && !ok {
			db.AddError(gorm.ErrMissingWhereClause)
			return
		}

		if !db.DryRun && db.Error == nil {
			result, err := db.Statement.ConnPool.ExecContext(db.Statement.Context, db.Statement.SQL.String(), db.Statement.Vars...)

			if err == nil {
				db.RowsAffected, _ = result.RowsAffected()
			} else {
				db.AddError(err)
			}
		}
	}
}

func AfterDelete(db *gorm.DB) {
	if db.Error == nil && db.Statement.Schema != nil && db.Statement.Schema.AfterDelete {
		callMethod(db, func(value interface{}, tx *gorm.DB) bool {
			if i, ok := value.(AfterDeleteInterface); ok {
				db.AddError(i.AfterDelete(tx))
				return true
			}
			return false
		})
	}
}