return &callback{before: name, processor: p}
}

func (p *processor) After(name string) *callback {
	return &callback{after: name, processor: p}
}

func (p *processor) Match(fc func(*DB) bool) *callback {
	return &callback{match: fc, processor: p}
}

func (p *processor) Register(name string, fn func(*DB)) error {
	return (&callback{processor: p}).Register(name, fn)
}

package schema

import (
	"regexp"
	"strings"

	"gorm.io/gorm/clause"
)

// reg match english letters and midline
var regEnLetterAndMidline = regexp.MustCompile(`^[\w-]+$`)

type CheckConstraint struct {
	Name       string
	Constraint string // length(phone) >= 10
	*Field
}

func (chk *CheckConstraint) GetName() string { return chk.Name }

func (chk *CheckConstraint) Build() (sql string, vars []interface{}) {

			}

			if c.before != "" {
				callMethod(v, "Before", c.before)
			}

			if c.after != "" {
				callMethod(v, "After", c.after)
			}

			if c.match != nil {
				callMethod(v, "Match", c.match)
			}

			if c.remove {
				callMethod(v, "Remove", c.name)
			} else if c.replace {
				callMethod(v, "Replace", c.name, c.h)
			} else {
				callMethod(v, "Register", c.name, c.h)

			if len(relations.Relations) != len(rs.Relations) {
				t.Errorf("schema relations count don't match, expects %d, got %d", len(rs.Relations), len(relations.Relations))
			}
			if len(relations.EmbeddedRelations) != len(rs.EmbeddedRelations) {
				t.Errorf("schema embedded relations count don't match, expects %d, got %d", len(rs.EmbeddedRelations), len(relations.EmbeddedRelations))
			}

	// ErrInvalidValue invalid value
	ErrInvalidValue = errors.New("invalid value, should be pointer to struct or slice")
	// ErrInvalidValueOfLength invalid values do not match length
	ErrInvalidValueOfLength = errors.New("invalid association values, length doesn't match")
	// ErrPreloadNotAllowed preload is not allowed when count is used
	ErrPreloadNotAllowed = errors.New("preload is not allowed when count is used")

	deleteCallback.Match(enableTransaction).Register("gorm:begin_transaction", BeginTransaction)
	deleteCallback.Register("gorm:before_delete", BeforeDelete)
	deleteCallback.Register("gorm:delete_before_associations", DeleteBeforeAssociations)
	deleteCallback.Register("gorm:delete", Delete(config))
	deleteCallback.Register("gorm:after_delete", AfterDelete)

		`"User__Company".*`:  {"User__Company", "*"},
		`"table"."*"`:        {"", ""},
	} {
		if table, column := matchName(k); table != v[0] || column != v[1] {
			t.Errorf("failed to match value: %v, got %v, expect: %v", k, []string{table, column}, v)
		}
	}

* Hooks (Before/After Create/Save/Update/Delete/Find)
* Eager loading with `Preload`, `Joins`
* Transactions, Nested Transactions, Save Point, RollbackTo to Saved Point
* Context, Prepared Statement Mode, DryRun Mode
* Batch Insert, FindInBatches, Find To Map
* SQL Builder, Upsert, Locking, Optimizer/Index/Comment Hints, NamedArg, Search/Update/Create with SQL Expr
* Composite Primary Key
* Auto Migrations
* Logger