This step calculates checksums for one or more fields in the input stream and adds this to the output as a new field.
为数据流输入的列计算校验码，并将输出作为新的一列。
wiki中介绍：http://wiki.pentaho.com/display/EAI/Add+a+checksum
| Option |
Description |
| Step name |
Name of the step. Note: This name has to be unique in a single transformation. |
| Type |
The type of checksum that needs to be calculated. These are the types that are available:
- CRC32 : 32-bit Cyclic Redundancy Check : http://en.wikipedia.org/wiki/Cyclic_redundancy_check
- ADLER 32 : Checksum algorithm by Mark Adler: http://en.wikipedia.org/wiki/Adler-32
- MD5 : Message Digest algorithm 5 : http://en.wikipedia.org/wiki/MD5
- SHA-1 : Secure Hash Algorithm 1 : http://en.wikipedia.org/wiki/SHA-1
|
| Result field |
The name of the result field containing the checksum |
| Fields used in the checksum |
The names of the fields to include in the checksum calculation.
Note: You can use the "Get Fields" button to insert all input fields from previous steps. |
注意，双击控件后，可以看到各种设置项。result field为新列的名称，一定要写。
这时候看到compatibility mode选项，打钩后，字段就会变得紧凑，不定长。默认为不选，是32位长的字段！
我为了比较字段，所以用定长。
如果想知道区别，做测试：
然后就preview rows，就可以看出两种结果的不同