Vizlib Writeback Table includes a Writeback Setup process to help you configure your writeback settings, leaving you to concentrate on working with your data rather than digging around trying to find the source. With Setup you can define columns, choose your data connection, choose the output for your results and even export the create script.
Before you can use Writeback Setup, you'll need to create a Writeback Table. Follow these instructions to get started.
Figure 1: Writeback Table Create
When Writeback setup opens, you'll be taken to the Select Destination dialog, where you'll be able to work with properties related to your data output (Figure 2). There are 4 properties you can select, and you can add them using the instructions here.
- Output Type sets the format for your exported results. Select one of the dropdown options.
- QVD-CSV-TXT - a file containing data.
Note: The Create App permissions is needed for QVD/CSV/TXT export
- REST - a REST operation response used with APIs..
- Database Connection - currently SQL (Snowflake, Redshift, BigQuery and Oracle will be available soon). Note: Vizlib Server is required to use the Database Connection output type. No freemium trial is available for Database connections.
- QVD-CSV-TXT - a file containing data.
Note: If you're working out whether to use an API or a file, it's worth considering how your data will be used. File output is great for managing smaller data sets which need to be accessed and interpreted quickly (a list of attendees for a conference). API output is suited to data sets which are updated frequently by multiple users, and the data potentially shared with other systems (a list of attendees looking to book appointments with conference exhibitors, or pre-registering for conference events).
- Operation sets the Writeback operation to write data to the Output Type. Select one of the dropdown options.
- Insert - New values inserted with every writeback.
- Overwrite - Existing values overwritten with every writeback.
- Update - New values inserted with every writeback, existing data unchanged.
- Data Connection sets the source for your writeback data. Select one of the dropdown options, or use the search function to find a connection.
Note: Data connections are configured in the Qlik Sense associative indexing engine, find out more about data connections in Qlik Sense here.
- Enter a File Name for your output, Click on qvd to select a file type, or click Choose to search for a file extension.
- Click Next to move to the Define Table Columns dialog.
Figure 2: Writeback Wizard - Select Destination
The Define Table Columns dialog (Figure 3) helps you to work with the columns in your writeback table, adding them, editing properties and also creating new columns.
The Define Table Columns dialog has a set of panels on the left, which contain values from the data connection you've chosen and a panel on the right which holds the columns you're adding to your writeback table. There are 3 types of data column you can add are listed here.
- Dimension - Dimensions are used to organise data into groups, e.g. a list of product types, or countries. They are defined in the data model loaded by the application hosting the writeback table, and can be added using Setup or Manual Configuration. You can add select a dimension already linked to a column in the data model, or you can choose to link to one of the Fields in the lower half of the dropdown.
- Measure - Measures are used for calculating data, e.g. the total sales for a product type sold, or the number of units sold per country. Like dimensions they are also defined in the data model using Qlik Sense aggregations, and can be added using Setup or Manual Configuration. You can select a measure which has an aggregation defined for a particular field, or select a field and add your own aggregation.
- Column - Columns can be added to display new data which hasn't been held in the data model, e.g. a comments section for each row. When the setup screen opens you'll find any existing values in the Fields section at bottom left. You can add a column using Setup or Manual Configuration, and select from a list of data types or utility types.
To start adding fields, follow the instructions here.
- Click the checkbox next to the data field you'd like to add, you should see the checkbox turn blue.
- Use the arrow to move the field into the right hand panel. To remove a column, select the field and click on the arrow.
- Once the field is added, you can edit several of the field properties.
- Change the column Type by clicking to open the dropdown.
- Select the Editable checkbox to allow changes to be made to the field (non-editable is the default).
- Add an Aggregation by clicking to open the dropdown.
- If you need to add a completely new column, click on the Create Writeback Column to open the Type dropdown.
- If you need to change the column order, drag and drop the column you want to move.
- Once you've set all your column properties, click Next to go to Generate Load Script.
Figure 3: Define Table Columns
Generate Load Script helps you work with the command which loads your column data to the output file (Figure 4). The dialog displays the table name, the load script and has 2 buttons - Inject to load script and Copy to clipboard
Figure 4: Generate Load Script
- If you don't need to edit anything, click on Inject to load script. When the process completes, the pop-up should appear.
- If you need to edit the script, click Copy to clipboard to open the data load editor in a new window (Figure 5), where you can make any changes.
Figure 5: Data Load Editor
Note: If you want to customize the security rules for your non root admin users, you will find more details here.
Once you've completed setting your Writeback table properties, click on Save in Generate Load Script to complete the wizard and display the table (Figure 6).
You can see the fields from figure 2 have all been added. If you do need to change any data properties you can either click on Open Setup in the property panel or select the field name in the Columns section and edit the properties there.
Figure 6: Writeback Wizard Complete