orm add sqlite3 support, may be support postgres in next commit

orm/db_mysql.go

@@ -1,11 +1,30 @@
 package orm
 
+var mysqlOperators = map[string]string{
+	"exact":     "= ?",
+	"iexact":    "LIKE ?",
+	"contains":  "LIKE BINARY ?",
+	"icontains": "LIKE ?",
+	// "regex":       "REGEXP BINARY ?",
+	// "iregex":      "REGEXP ?",
+	"gt":          "> ?",
+	"gte":         ">= ?",
+	"lt":          "< ?",
+	"lte":         "<= ?",
+	"startswith":  "LIKE BINARY ?",
+	"endswith":    "LIKE BINARY ?",
+	"istartswith": "LIKE ?",
+	"iendswith":   "LIKE ?",
+}
+
 type dbBaseMysql struct {
 	dbBase
 }
 
-func (d *dbBaseMysql) GetOperatorSql(mi *modelInfo, operator string, args []interface{}) (sql string, params []interface{}) {
-	return d.dbBase.GetOperatorSql(mi, operator, args)
+var _ dbBaser = new(dbBaseMysql)
+
+func (d *dbBaseMysql) OperatorSql(operator string) string {
+	return mysqlOperators[operator]
 }
 
 func newdbBaseMysql() dbBaser {