Help Center/ MapReduce Service/ Component Operation Guide (LTS)/ Using HBase/ In-House Enhanced BulkLoad Tool/ Importing Data with Indexes in a Customized Manner/ Combining Rowkeys
Updated on 2022-11-18 GMT+08:00
View PDF

Combining Rowkeys

Scenario

You can combine rowkeys in a customized manner. Combining rowkeys using BulkLoad is to process some column names in a customized manner using some rules and combine them to generate a new rowkey.

The column name consists of letters, digits, and underscores and cannot contain any special characters.

Configuration Method

Details about how to set configuration.xml to combine rowkeys are as follows:

For example, combine column SMS_ID, the second to fourth characters of column SMS_NAME, and the reverse of column SMS_SERAIL.

 <columns> 
                         <column index="1" type="int">SMS_ID</column> 
                         <column index="2" type="string">SMS_NAME</column> 
                         <column index="3" type="string">SMS_ADDRESS</column> 
                 </columns> 
                 <rowkey> 
                        SMS_ID+'_'+substring(SMS_NAME,1,4)+'_'+reverse(SMS_ADDRESS)
                 </rowkey>
Table 1 Rowkey segment process functions

Function Prototype

Description

Example

format(data,"DataType")

Used to format string data.

For example, format(data,"0.000") is used to input data in "0.000" format.

converse(data,"yyyy-MM-dd","yyyyMMdd")

Used to convert the date format.

For example, converse(data,"yyyy-MM-dd","yyyyMMdd") is used change the date format from "yyyy-MM-dd" to "yyyyMMdd".

rand

Used to generate a random number. Only the int type is supported.

None

replace(data,"A","B")

Used to replace data.

replace(data,"A","B") is used to replace A with B.

reverse(data)

Used to reverse a character string.

For example, reverse(ABC) is used reverse "ABC" to "CBA".

substring(data,Length1,Length2), or substring(data,Length3)

Used to subtract a character string.

For example, substring(data,1,5), or substring(data,3) is used to subtract [1,5) or [3,data.length) from the data character string.

to_number("data")

Used to convert a character string into a numeric value. The Long type numeric value is supported.

For example, to_number("123") is used to convert "123" into 123. Note that "data" must be a numerical value.