if err != nil {
		t.Errorf("AutoMigrate err:%v", err)
	}

	ct, err := findColumnType(&DiffType{}, "name")
	if err != nil {
		t.Errorf("findColumnType err:%v", err)
	}

	AssertEqual(t, "varchar", strings.ToLower(ct.DatabaseTypeName()))

	err = DB.Table("diff_types").AutoMigrate(&DiffType1{})
	if err != nil {
		t.Errorf("AutoMigrate err:%v", err)
	}

          "expr": "rate(minio_node_io_rchar_bytes{job=~\"$scrape_jobs\"}[$__rate_interval])",
          "format": "time_series",
          "instant": false,
          "interval": "",
          "legendFormat": "Node RChar [{{server}}]",
          "refId": "A"
        },
        {
          "datasource": {
            "type": "prometheus",
            "uid": "${DS_PROMETHEUS}"
          },
          "exemplar": true,