使用命令行时如何使用 CQL 获取当前时间戳? [英] How to get current timestamp with CQL while using Command Line?

问题描述

我正在尝试从命令行插入到我的 CQL 表中.我能够插入所有内容.但我想知道我是否有时间戳列，那么如何从命令行插入时间戳列?基本上，每当我插入 CQL 表时，我都想插入当前时间戳 -

I am trying to insert into my CQL table from the command line. I am able to insert everything. But I am wondering if I have a timestamp column, then how can I insert into timestamp column from the command line? Basically, I want to insert current timestamp whenever I am inserting into my CQL table -

目前，每当我插入下面的 CQL 表时，我都会对时间戳进行硬编码 -

Currently, I am hardcoding the timestamp whenever I am inserting into my below CQL table -

CREATE TABLE TEST (ID TEXT, NAME TEXT, VALUE TEXT, LAST_MODIFIED_DATE TIMESTAMP, PRIMARY KEY (ID));

INSERT INTO TEST (ID, NAME, VALUE, LAST_MODIFIED_DATE) VALUES ('1', 'elephant',  'SOME_VALUE', 1382655211694);

有什么方法可以使用 CQL 中的一些预定义函数获取当前时间戳，以便在插入上表时，我可以使用该方法获取当前时间戳，然后插入到上表中?

Is there any way to get the current timestamp using some predefined functions in CQL so that while inserting into above table, I can use that method to get the current timestamp and then insert into above table?

推荐答案

您可以使用 timeuuid 函数 now() 和 dateof()(或在更高版本的Cassandra，toTimestamp())，例如，

You can use the timeuuid functions now() and dateof() (or in later versions of Cassandra, toTimestamp()), e.g.,

INSERT INTO TEST (ID, NAME, VALUE, LAST_MODIFIED_DATE)
                  VALUES ('2', 'elephant',  'SOME_VALUE', dateof(now()));

now 函数不接受任何参数并生成一个新的唯一 timeuuid(在执行使用它的语句时).dateOf 函数接受一个 timeuuid 参数并提取嵌入的时间戳.(取自关于 timeuuid 函数的 CQL 文档).

The now function takes no arguments and generates a new unique timeuuid (at the time where the statement using it is executed). The dateOf function takes a timeuuid argument and extracts the embedded timestamp. (Taken from the CQL documentation on timeuuid functions).

dateof() 在 Cassandra 2.2.0-rc2 中已弃用.对于更高版本，您应该将其使用替换为 toTimestamp()，如下所示:

dateof() was deprecated in Cassandra 2.2.0-rc2. For later versions you should replace its use with toTimestamp(), as follows:

INSERT INTO TEST (ID, NAME, VALUE, LAST_MODIFIED_DATE)
                  VALUES ('2', 'elephant',  'SOME_VALUE', toTimestamp(now()));

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