Using Macro Variables of Date and Time

dateformat

dateformat supports two types of parameters:

• dateformat(format)

  format indicates the date and time format. For details about the format definition, see the definition in java.text.SimpleDateFormat.java.

  For example, if the current date is 2017-10-16 09:00:00, yyyy-MM-dd HH:mm:ss indicates 2017-10-16 09:00:00.

• dateformat(format, dateOffset, dateType)
  • format indicates the format of the returned date.
  • dateOffset indicates the date offset.
  • dateType indicates the type of the date offset.

    Currently, dateType supports SECOND, MINUTE, HOUR, MONTH, YEAR, and DAY.

    

    Pay attention to the following special scenarios of MONTH and YEAR:

    • If the date does not exist after the offset, the latest date of the month in the calendar is used.
    • These two offset types cannot be used for the start time and end time in the Time Filter parameter of the source and destination jobs.

  For example, if the current date is 2023-03-01 09:00:00, then:

  • dateformat(yyyy-MM-dd HH:mm:ss, -1, YEAR) indicates the year before the current time, that is, 2022-03-01 09:00:00.
  • dateformat(yyyy-MM-dd HH:mm:ss, -3, MONTH) indicates three months before the current time, that is, 2022-12-01 09:00:00.
  • dateformat(yyyy-MM-dd HH:mm:ss, -1, DAY) indicates the day before the current time, that is, 2023-02-28 09:00:00.
  • dateformat(yyyy-MM-dd HH:mm:ss, -1, HOUR) indicates one hour before the current time, that is, 2023-03-01 08:00:00.
  • dateformat(yyyy-MM-dd HH:mm:ss, -1, MINUTE) indicates one minute before the current time, that is, 2023-03-01 08:59:00.
  • dateformat(yyyy-MM-dd HH:mm:ss, -1, SECOND) indicates one second before the current time, that is, 2023-03-01 08:59:59.

timestamp

timestamp supports two types of parameters:

• timestamp()

  Indicates the returned timestamp of the current time, that is, the number of milliseconds that have elapsed since 00:00:00 on January 1, 1970 (1970-01-01 00:00:00 GMT). For example, 1508078516286.

• timestamp(dateOffset, dateType)

  Indicates the timestamp returned after time offset. dateOffset and dateType indicate the date offset and the offset type, respectively.

  For example, if the current date is 2017-10-16 09:00:00, timestamp(-10, MINUTE) indicates that the timestamp generated 10 minutes before the current time point is returned, that is, 1508115000000.

Macro Variable Definition of Time and Date

Suppose that the current time is 2017-10-16 09:00:00, then Table 1 describes the macro variable definitions of time and date.

The examples in the table must be embedded in ''. For example, '${dateformat(yyyy-MM-dd)}' returns the current time in yyyy-MM-dd format.

Time and Date Macro Variables of Paths and Table Names

After the macro definition conversion, this job indicates that data in table SQOOP.CDM_20171016 in the Oracle database is migrated to the /opt/ttxx/1508115701746 directory of the HDFS server.

Figure 1 Setting Table Name and Write Directory to a time and date macro variable

Currently, a table name or path name can contain multiple macro variables. For example, /opt/ttxx/${dateformat(yyyy-MM-dd)}/${timestamp()} is converted to /opt/ttxx/2017-10-16/1508115701746.

Time and Date Macro Variables in the Where Clause

Figure 2 uses table SQOOP.CDM_20171016 as an example. The table contains column DS, which indicates the time.

Figure 2 Table data

Suppose that the current date is 2017-10-16 and you want to export data generated the day before the current day (DS = 2017-10-15), then you can set the value of Where Clause to DS='${dateformat(yyyy-MM-dd,-1,DAY)}' when creating a job. In this way, you can export all data that complies with the DS = 2017-10-15 condition.

Implementing Incremental Synchronization by Configuring the Macro Variables of Date and Time and Scheduled Jobs

Two simple application scenarios are as follows:

• The database table contains column DS that indicates the time, the value type of the column is varchar(30), and the inserted time format is similar to 2017-xx-xx.

  In a scheduled job, the cycle is one day, and the scheduled job is executed at 00:00:00 every day. Set the value of Where Clause to DS='${dateformat(yyyy-MM-dd,-1,DAY)}', and then data generated in the previous day will be exported at 00:00:00 every day.

• The database table contains column time that indicates the time, the type is Number, and the inserted time format is timestamp.

  In a scheduled job, the cycle is one day, and the scheduled job is executed at 00:00:00 every day. Set the value of Where Clause to time between ${timestamp(-1,DAY)} and ${timestamp()}, and then data generated on the previous day will be exported at 00:00:00 every day.

Configuration principles of other application scenarios are the same.