Setting up column definitions on a link (Source)
Column definitions, which you set on a link, specify the format of the data records that the connector reads from or writes to a data source.
About this task
Which column definitions you set depend on the read mode and the format of the Azure Storage files. The following table shows how the read mode affects the requirements for column definitions.
- From the job design canvas, double-click the connector icon..
Use one of the following methods to set up the column definitions:
- Drag a table definition from the repository view to the link on the job canvas. Then, use the arrow buttons to move the columns between the Available columns and Selected columns lists.
- On the Columns page, click Load and select a table definition from the metadata repository. Then, to choose which columns from the table definition apply to the link, move the columns from the Available columns list to the Selected columns list.
- A column in this tab represents the column from the Cassandra table. The values entered in this field overrides Column name field. So, you can use different column name than its name in the table definition by putting actual name in the Description field. The Description field can be also used to denote that a given column should be converted to JSON (using Cassandra functions tojson() and fromjson()). If you want to have the column to be converted to, or from JSON, you should use json() function in Description column. For example: to convert column named phone_numbers to JSON you should use: json(phone_numbers).
- One or more columns defined in this tab must be marked as key column.
Configure the properties for the columns:
- Right-click within the columns grid, and select Properties from the menu.
- Select the properties to display, specify the order in which to display them, and then click OK.
- Optional: Modify the column definitions. You can change the column names, data types, and other attributes. In addition, you can add, insert, or remove columns.
- Optional: Save the new table definition in the metadata repository
On the Columns page, click Save, and then click OK to display the repository view.
- Navigate to an existing folder, or create a new folder in which to save the table definition.
- Select the folder, and then click Save.