Defining Hashed File Input Data
When you write data to a hashed file, the Hashed File stage has an input link. The properties of this link and the column definitions of the data are defined on the Inputs page in theHashed File Stage dialog box.
The Inputs page has the following field and two tabs:
- Input name. The name of the input link. Choose the link you want to edit from the Input name list. This list displays all the input links to the Hashed File stage.
- General.
Displayed by default. Contains the following fields and options:
- File name. The name of the file the data is written to. You can either use a job parameter to represent the file created during run time or choose the file from the File name list. This list contains all the files defined in the ►Account name folder in the repository, where Account name is the name of the account chosen on the Stage page. By default the name of the input link is used as the file name. If the file you want is not listed, you need to define a table definition.
- Clear file before writing. If you select this check box, the existing file is cleared and new data records are written to the empty file. This check box is cleared by default.
- Backup existing file. If you select this check box, a backup copy of the existing file is made before the new data records are written to the file. The backup can be used to reset the file if a job is stopped or aborted at run time. This check box is cleared by default.
- Allow stage write cache. Select this check box to specify that all records should be cached, rather than written to the hashed file immediately. Avoid this when your job writes and reads to the same hashed file in the same stream of execution, for example, where a Transformer stage checks if a record already exists to determine the required operation. (If you have caching on the server enabled, any caching attributes that the file was created with will override the stage-level caching).
- Create File. Select this check box to specify that the stage will create the hashed file for writing to. Click Options to open the Create file options dialog box to specify details about how the file is created (see Create File Options).
- Description. Contains an optional description of the input link.
- Columns.
Contains the column definitions for the data written to the file.
Note: You should use the Key check boxes to identify the key columns. If you don't, the first column definition is taken as the hashed file's key field. The remaining columns dictate the order in which data will be written to the hashed file. Do not reorder the column definitions in the grid unless you are certain you understand the consequences of your action.
Click View Data... to open the Data Browser. This enables you to look at the data associated with the input link. For a description of the Data Browser, see Using the Data Browser.