diff --git a/model/t_uid/t_uid.go b/model/t_uid/t_uid.go
new file mode 100644
index 0000000..48a196e
--- /dev/null
+++ b/model/t_uid/t_uid.go
@@ -0,0 +1,139 @@
+package t_uid
+
+import (
+	"fmt"
+	"time"
+
+	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
+	"qoobing.com/gomod/log"
+)
+
+type t_uid struct {
+	F_id           int64     `gorm:"column:F_id;primaryKey"` // ID范围id
+	F_pid          int64     `gorm:"column:F_pid"`           // ID范围的前一个范围id
+	F_type         string    `gorm:"column:F_type"`          // ID类型
+	F_prefix       string    `gorm:"column:F_prefix"`        // ID前缀(type+prefix+range_start唯一)
+	F_range_start  int64     `gorm:"column:F_range_start"`   // ID范围的起始id
+	F_range_length int       `gorm:"column:F_range_length"`  // ID范围的长度
+	F_range_owner  string    `gorm:"column:F_range_owner"`   // ID范围的拥有者，一般是机器id
+	F_create_time  time.Time `gorm:"column:F_create_time"`   // 记录创建时间
+}
+
+type typeInfo struct {
+	Name        string //type name
+	RangeLength int    //Range length
+}
+
+var table string = "t_uid" // id range table name
+var typeSupported = map[string]typeInfo{
+	"TXID": typeInfo{
+		Name:        "TXID",
+		RangeLength: 3,
+	},
+	"USERID": typeInfo{
+		Name:        "USERID",
+		RangeLength: 3,
+	},
+}
+
+func Init(tablename string) {
+	table = tablename
+}
+
+func (id *t_uid) TableName() string {
+	return table
+}
+
+func (id *t_uid) BeforeCreate(db *gorm.DB) error {
+	id.F_create_time = time.Now()
+	return nil
+}
+
+func (id *t_uid) BeforeUpdate(db *gorm.DB) (err error) {
+	return nil
+}
+
+func CreateIdRange(db *gorm.DB, typ, prefix string) (start int64, length int, err error) {
+	// Step 1. init variables
+	if t, ok := typeSupported[typ]; !ok {
+		panic(fmt.Sprintf("id type [%s] not supported yet", typ))
+	} else {
+		length = t.RangeLength
+	}
+	var (
+		lock     = clause.Locking{Strength: "UPDATE"}
+		root     = t_uid{}
+		rootcond = map[string]interface{}{
+			"F_type":   fmt.Sprintf("%s#ROOT", typ),
+			"F_prefix": prefix,
+			"F_pid":    0,
+		}
+		rootattr = map[string]interface{}{
+			"F_range_start":  -length,
+			"F_range_length": length,
+			"F_range_owner":  "0",
+		}
+		selfid = "TODO"
+	)
+
+	// Step 2. get lastid && lock root(type+prefix)
+	var tx = db.Begin()
+	var txsuccess = false
+	defer func() {
+		if !txsuccess {
+			tx.Rollback()
+		}
+	}()
+	txr := tx.Clauses(lock).
+		Where(rootcond).
+		Attrs(rootattr).
+		FirstOrCreate(&root)
+	if txr.Error != nil {
+		return 0, 0, txr.Error
+	}
+	if root.F_range_owner == "0" {
+		// for new created root we set owner to itself.
+		root.F_range_owner = fmt.Sprintf("%d", root.F_id)
+	}
+	log.PrintPretty("root:", root)
+
+	// Step 3. insert new range. [can DELETE this for perfermance]
+	var newrange = t_uid{
+		F_type:         typ,
+		F_prefix:       prefix,
+		F_range_start:  root.F_range_start + int64(length),
+		F_range_length: length,
+		F_range_owner:  selfid,
+	}
+	if n, e := fmt.Sscanf(root.F_range_owner, "%d", &newrange.F_pid); e != nil {
+		log.Debugf("sscanf F_range_owner(%s) failed: '%s'", root.F_range_owner, e)
+		return 0, 0, fmt.Errorf("range_owner error")
+	} else if n != 1 {
+		log.Debugf("sscanf F_range_owner(%s) failed: n=%d", root.F_range_owner, n)
+		return 0, 0, fmt.Errorf("range_owner error")
+	}
+	if txr := tx.Create(&newrange); txr.Error != nil {
+		log.PrintPretty("newrange:", newrange)
+		return 0, 0, txr.Error
+	}
+
+	// Step 4. update root
+	root.F_range_start = newrange.F_range_start
+	root.F_range_length = newrange.F_range_length
+	root.F_range_owner = fmt.Sprintf("%d", newrange.F_id)
+	if txr := tx.Save(&root); txr.Error != nil {
+		return 0, 0, txr.Error
+	}
+
+	// Step 5. commit and return
+	if txr := tx.Commit(); txr.Error != nil {
+		return 0, 0, txr.Error
+	}
+
+	txsuccess = true
+	start = newrange.F_range_start
+	length = newrange.F_range_length
+	log.Infof("create range success:(%s, %s, %d, %d)", typ, prefix, start, length)
+	return start, length, nil
+}