# Column mappings Information note For improved metadata performance during discovery and mapping, Compose caches the metadata of the Landing Zones after reading them. However, synchronization issues may arise if the Landing Zone is modified outside of Compose. In such cases, you should click **Clear Landing Cache** in the **Mappings** tab of the **Storage Zone** panel in order to refresh the cache on the next reading of the metadata. For details on recreating the Storage Zone cache, see [Clearing the metadata cache](https://help.qlik.com/en-US/compose/December2024/Content/ComposeDWDL/Main/DL/Model/Recreating%20the%20Storage%20Zone%20Metadata%20Cache.htm). The mappings show the current mapping between the Landing Zone tables and the Storage Zone tables. By default, the columns names and data in the Landing Zone tables and the Storage Zone tables will be identical. However, you can manually change the mappings according to your needs, either by simply mapping a Landing Zone column to a different Storage Zone column and/or by using an expression. ## Limitations and considerations * Creating multiple mappings for a single table is not supported. * Mapping from Views is not supported. ## Editing column mappings To edit column mappings: 1. Click the **Manage** button in the **Storage Zone** panel. The **Mappings** tab is displayed. Each of the Storage Zone tables has a corresponding mapping name. 2. In the **Mappings** column, click the mapping that you want to edit. The **Edit Mapping: Name** window opens. 3. Edit the mapping as described in the table below. | **To** | **Do This** | | --- | --- | | [](https://help.qlik.com/en-US/compose/Content/ComposeDWDL/Main/DL/Storage%20Zone/edit_column_mappings_hive.htm)Map a column in a Landing Zone table to a column in a Storage Zonetable | Information note

The mapping procedure differs depending on whether you are in Standard View or Compact View. For information on changing the view, see [Change the view](https://help.qlik.com/en-US/compose/December2024/Content/ComposeDWDL/Main/DL/Storage%20Zone/edit_column_mappings_hive.htm#change_view).

**In Standard View:**

  1. Hover the mouse cursor over the Landing Zone column name as shown in the image below.

    A gray dot appears to the right of the column name.

  2. Drag the mouse cursor from the gray dot to the desired column in the Storage Zone table.

  3. When the dotted line turns green (as shown below), release your mouse button.

    The mapping operation is completed.

    Note that if the dotted line turns red (instead of a green), you will not be able to map the Landing Zone column with the desired Storage Zone column. A red dotted line indicates that the Landing Zone and Storage Zone column data types are incompatible with each other.



**In Compact View:**

  1. Switch to Compact View as described in Change the view.
  2. Drag the Landing Zone column to the cell located to the left of the target Storage Zone column.
| | Auto-generate mapping | Click the **Auto-Map** toolbar button. | | Remove all mappings | Click the **Reset** toolbar button. | | [](https://help.qlik.com/en-US/compose/Content/ComposeDWDL/Main/DL/Storage%20Zone/edit_column_mappings_hive.htm)Change the view | Changing to a more compact view is recommended for Landing Zone tables that have numerous columns. In compact view, the table columns are organized in rows (instead of a single list), making it easier to locate Landing Zone columns and map them to the desired Storage Zone columns.

**To change the view:**

Click the **Change View** toolbar button. For information on creating mappings in Compact view, see [Map a column in a Landing Zone table to a column in a Data Lake table.](https://help.qlik.com/en-US/compose/December2024/Content/ComposeDWDL/Main/DL/Storage%20Zone/edit_column_mappings_hive.htm#Map_column) | | Select a different source database | Select a database from the **Landing Zone Database** drop-down list on the left of the window. | | Select a different source schema | Select a schema from the **Schema** drop-down list on the left of the window. | | Select a different table | Select a table from the **Table** drop down list on the left of the window. | | Create a column-level transformation |

  1. Hover the mouse cursor over the Storage Zone Column for which you want to create a transformation and then click the fx button that appears to its right.

    The Expression Builder opens.

  2. Continue from Creating transformations.
| ## Adding, renaming and deleting mappings You can add, rename and delete mappings as required. For example, if you want one of the Storage Zone tables to contain columns from several tables in the Landing Zone, then you need to add a new mapping for each of the Landing Zone tables. To add, delete, and rename mappings: 1. Click the **Manage** button in the **Storage Zone** panel. The **Manage** **task** **Tasks** window opens. 2. In the left pane, select the desired task**Task**. 3. Select the Mappings tab. 4. Add or delete mappings as described in the following table. | **To** | **Do This** | | --- | --- | | Add a new mapping |
  1. In the Data Lake Tables column, select the table that you want to map.

  2. Click the NewMapping button above the Delivery Tables column.

    The New Mapping window opens.

  3. Optionally change the default mapping name.
  4. From the Entity drop-down list, select the entity in the Storage Zone to which you want to map.
  5. Click OK to save the mapping.
  6. Enable the mapping.
| | Delete a mapping |
  1. In the Mappings column, hover the mouse cursor over the mapping you want to delete.
  2. Click the Delete(x) button that appears to its right.
  3. Click OK when prompted to confirm the deletion.
| | Rename a mapping |
  1. In the Mappings column, hover the mouse cursor over the mapping you want to rename.

  2. Click the Rename (A) button that appears to its right.

    The Rename window opens.

  3. Specify a new name for the mapping and then click OK.
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