GoCQL：将字符串编组为时间戳

Question

我正在开发一个带有聚类列的时间序列数据模型，即

CREATE TABLE events (
    id text,
    time timestamp,
    type text,
    val double,
    PRIMARY KEY (id, time)
) WITH CLUSTERING ORDER BY (time DESC)

我希望对分区列 'id' 和集群列 'time' 执行 select。例如id:='1',timestamp:='2017-10-09'

query := "SELECT id, time, type, val FROM events WHERE id=? AND time>=?"
iterable := Cassandra.Session.Query(query, id, timestamp).Consistency(gocql.One).Iter()
for iterable.MapScan(m) {
        found = true
        event = Event{
                ID:       m["id"].(string),
                Time:     m["time"].(time.Time),
                Type:     m["type"].(string),
                Val:      m["val"].(float64),
        }
}

检查 iterable.Close() 错误后，发现编组错误

{"errors":["can not marshal string into timestamp"]}

我该如何解决这个问题？

Answer 1

这是我最终通过将字符串文字（时间戳）转换为类型 time.Time

来解决这个问题的方法

timestamp = "2017-10-09T13:25:00.000Z"
tsAfter,err = time.Parse(model.TimeLayout, timestamp)
if err != nil {
    errs = append(errs, err.Error())
}

log.Printf("GET param [id = %s]", idStr)
log.Printf("GET param [after = %s]", tsAfter.String())

m := map[string]interface{}{}
query := "SELECT id, time, type, val FROM events WHERE id = ? AND time >= ?"
iterable := cql.Session.Query(query, idStr, tsAfter).Consistency(gocql.One).Iter()

for iterable.MapScan(m) {
    eventList = append(eventList, model.Event{
        ID:         m["id"].(string),
        Time:       m["time"].(time.Time),
        Type:       m["type"].(string),
        Val:        m["val"].(float64),
    })
    m = map[string]interface{}{}
}

GoCQL：将字符串编组为时间戳

GoCQL : Marshal string into timestamp

cql

go

gocql