显示缓冲区类型数据的 cassandra timeuuid 列 insted of string

Question

我正在使用 NodeJS Cassandra 驱动程序从 Cassandra timeuuid 列检索数据。现在，数据检索为缓冲区类型而不是字符串类型。我需要字符串类型的数据

Answer 1

虽然仍然难以理解您期望看到的内容，但这将 return 您的 PostedDate 以更易读的格式：

SELECT DateOf(PostedDate) FROM facehq.timeline;

此外，随着数据量的增加，未绑定的查询将变得有问题且速度变慢。因此，请确保尽可能使用 WHERE 子句限定此类查询。

i need result like "posteddate":"f6ca25d0-ffa4-11e4-830a-b395dbb548cd".

在我看来，您的问题似乎出在 node.js 代码中。您如何执行查询？ Node.js driver documentation on the GitHub project page 有一个可能有帮助的例子：

client.stream('SELECT time, val FROM temperature WHERE station_id=', ['abc'])
  .on('readable', function () {
    //readable is emitted as soon a row is received and parsed
    var row;
    while (row = this.read()) {
      console.log('time %s and value %s', row.time, row.val);
    }
  })
  .on('end', function () {
    //stream ended, there aren't any more rows
  })
  .on('error', function (err) {
    //Something went wrong: err is a response error from Cassandra
  });

DataStax 文档也有针对 working with timeUUIDs 的具体示例：

client.execute('SELECT id, timeid FROM sensor', function (err, result) {
    assert.ifError(err);
    console.log(result.rows[0].timeid instanceof TimeUuid); // true
    console.log(result.rows[0].timeid instanceof Uuid); // true, it inherits from Uuid
    console.log(result.rows[0].timeid.toString());      // <- xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
    console.log(result.rows[0].timeid.getDate());       // <- Date stored in the identifier
});

显示缓冲区类型数据的 cassandra timeuuid 列 insted of string

cassandra timeuuid columns showing buffer type data insted of string

node.js

cassandra

cql

timeuuid