diff --git a/engine.go b/engine.go
index dab313be..b6207706 100644
--- a/engine.go
+++ b/engine.go
@@ -227,6 +227,8 @@ func (engine *Engine) MapType(t reflect.Type) *Table {
 						col.Default = tags[j+1]
 					case k == "text":
 						col.SQLType = Text
+					case k == "blob":
+						col.SQLType = Blob
 					case strings.HasPrefix(k, "int"):
 						if k == "int" {
 							col.SQLType = Int
@@ -396,6 +398,24 @@ func (e *Engine) CreateTables(beans ...interface{}) error {
 	return session.Commit()
 }
 
+func (e *Engine) DropTables(beans ...interface{}) error {
+	session := e.NewSession()
+	err := session.Begin()
+	defer session.Close()
+	if err != nil {
+		return err
+	}
+
+	for _, bean := range beans {
+		err = session.DropTable(bean)
+		if err != nil {
+			session.Rollback()
+			return err
+		}
+	}
+	return session.Commit()
+}
+
 func (e *Engine) CreateAll() error {
 	session := e.NewSession()
 	err := session.Begin()
diff --git a/session.go b/session.go
index 42993d56..f68257ff 100644
--- a/session.go
+++ b/session.go
@@ -335,22 +335,14 @@ func (session *Session) CreateTable(bean interface{}) error {
 	defer statement.Init()
 	statement.RefTable = session.Engine.AutoMap(bean)
 	sql := statement.genCreateSQL()
-	res, err := session.Exec(sql)
-	if err != nil {
-		return err
-	}
-
-	affected, err := res.RowsAffected()
-	if err != nil {
-		return err
-	}
-	if affected > 0 {
+	_, err := session.Exec(sql)
+	if err == nil {
 		sql = statement.genIndexSQL()
 		if len(sql) > 0 {
 			_, err = session.Exec(sql)
 		}
 	}
-	if err == nil && affected > 0 {
+	if err == nil {
 		sql = statement.genUniqueSQL()
 		if len(sql) > 0 {
 			_, err = session.Exec(sql)
@@ -359,6 +351,15 @@ func (session *Session) CreateTable(bean interface{}) error {
 	return err
 }
 
+func (session *Session) DropTable(bean interface{}) error {
+	statement := session.Statement
+	defer statement.Init()
+	statement.RefTable = session.Engine.AutoMap(bean)
+	sql := statement.genDropSQL()
+	_, err := session.Exec(sql)
+	return err
+}
+
 func (session *Session) Get(bean interface{}) (bool, error) {
 	statement := session.Statement
 	defer statement.Init()
diff --git a/statement.go b/statement.go
index b734a167..7fc28885 100644
--- a/statement.go
+++ b/statement.go
@@ -244,7 +244,7 @@ func (statement *Statement) genCreateSQL() string {
 func (statement *Statement) genIndexSQL() string {
 	var sql string = ""
 	for indexName, cols := range statement.RefTable.Indexes {
-		sql += fmt.Sprintf("CREATE INDEX IF NOT EXISTS IDX_%v_%v ON %v (%v);", statement.TableName(), indexName,
+		sql += fmt.Sprintf("CREATE INDEX IDX_%v_%v ON %v (%v);", statement.TableName(), indexName,
 			statement.TableName(), strings.Join(cols, ","))
 	}
 	return sql
@@ -253,7 +253,7 @@ func (statement *Statement) genIndexSQL() string {
 func (statement *Statement) genUniqueSQL() string {
 	var sql string = ""
 	for indexName, cols := range statement.RefTable.Uniques {
-		sql += fmt.Sprintf("CREATE UNIQUE INDEX IF NOT EXISTS UQE_%v_%v ON %v (%v);", statement.TableName(), indexName,
+		sql += fmt.Sprintf("CREATE UNIQUE INDEX UQE_%v_%v ON %v (%v);", statement.TableName(), indexName,
 			statement.TableName(), strings.Join(cols, ","))
 	}
 	return sql
diff --git a/testbase.go b/testbase.go
index 4e237f0f..6ae6edef 100644
--- a/testbase.go
+++ b/testbase.go
@@ -41,7 +41,13 @@ type Userdetail struct {
 }
 
 func directCreateTable(engine *Engine, t *testing.T) {
-	err := engine.CreateTables(&Userinfo{})
+	err := engine.DropTables(&Userinfo{})
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	err = engine.CreateTables(&Userinfo{})
 	if err != nil {
 		t.Error(err)
 	}