Introduction
Workflow variables in Joget are key data elements that are essential for the overall operation and flow of a process. Unlike data specific to individual forms or activities, workflow variables have a broader scope and are used throughout the entire process.
Distinction between normal data and workflow variables
For example, consider a Leave Application process where form data like application date, leave duration, and reason are specific to each application. They are used for record-keeping and informing supervisors about the leave request but do not control the workflow.
Workflow variables, on the other hand, are elements that carry significant weight in determining the flow of the process. In the Leave Application process, a good example of a workflow variable could be "supervisorApproval". This variable might store a value like "approved" or "rejected". The value of this variable is used to decide the next steps in the workflow. For example, if "supervisorApproval" is "approved", the process might move to the HR department for final processing. This variable becomes crucial when a supervisor's decision (accept or reject) alters the course of the workflow, triggering different activities or decisions.
Here is a screenshot from a sample app showing a process builder and workflow variable initialization.
Figure 1: Process Builder and Workflow Variable
Form Fields and Workflow Variables in Joget
Form Fields
Purpose and Usage: Form fields in Joget are primarily designed for user input and data display within a specific form. They are the interface elements that users interact with, such as text boxes, dropdowns, or date pickers.
Scope: The data entered or displayed in form fields is specific to that form instance. It's mainly used for capturing and displaying information relevant to a single step or part of the process. For advanced usage, the form data can be used within the App using the Form Data Hash Variable which increases the scope to a global level (allowing usage in other parts of the App).
Storage: Data from form fields is typically stored in the application's database and is associated with the specific instance of the form. It's accessible whenever the form is loaded or referenced (using Form Hash Variables).
Workflow Variables in Joget
Their primary role is to facilitate decision-making and condition handling within the workflow in the process builder.
Scope: Unlike form fields, workflow variables have a process-wide scope. They maintain their values across different forms and activities in a workflow, making them ideal for passing data between steps in a process.
Influence on Process Flow: Workflow variables are often used to control process routing, conditions, and decision points within a workflow. Their values can determine which path a process takes, or which activities are triggered next.
Example
In Joget, a form field and a workflow variable, even if named similarly (e.g., both called "status"), are distinct entities. A form field is specific to a form and is used to capture user input, while a workflow variable is a broader process-level variable that can influence and guide the workflow's progression and routes taken. So in this case, the 'status' variable is also stored in different database tables.
Storage: Stored on a database table separate from the form data. These variables are stored in the "shkactivitydata" database table and are not to be tampered with for reasons mentioned below in the section Storage mechanisms for form data variables and workflow variables.
Key Concepts
Hash Variables
In Joget, a Hash Variable is a specialized, hash-escaped keyword that has a wide range of applications across different components of the platform. It can be used in the Form Builder, List Builder, and UI Builder to dynamically retrieve and display the values of runtime variables.
Example- #date.D-MMM-yyyy# (date hash variable).
It is recommended to read this article to have a clearer understanding of what hash variables are.
Populate Data dynamically
For functionalities like populating an email body, both form data (accessed via # form.table.status #) and workflow variables (# variable.status #) can be utilized, offering flexibility in how data is referenced within the workflow.
Please do keep in mind that it is important to not confuse the form data with workflow variables. As explained before, they are separate entities but both entities can be used as hash variables for use inside, for example, an email body.
Update Mechanisms
Form Data Update Tool: This built-in tool is used to update values directly in the database. To use this go to Process Builder> Tools> Mapping> Select Update Form Data> Update Fields.
The changes made using this tool affect the data stored in form fields. This tool ensures that any changes or entries made to form fields are correctly reflected in the database, without needing manual input, directly within the workflow process.
Figure 2: Form Data Update Tool in Process Builder
Workflow Variable Update Tool: Available at the marketplace, the Workflow Variable Update Tool updates the value of workflow variables. To use this go to Process Builder> Tools> Mapping> Select Workflow Variable Update Tool> Workflow Variable Mapping.
It's used when there's a need to modify the values of variables that control or influence the workflow process.
Figure 3: Workflow Variable Update Tool in Process Builder
Besides the Workflow Variable Update plugin, BeanShell scripting can also be used to update workflow variables. While BeanShell scripting provides a flexible way to manage workflow variables, the Workflow Variable Update Tool is often preferred for its user-friendliness, especially for users who might not be comfortable with scripting.
It only takes a couple of lines of code to set the value into a workflow variable:
import org.joget.workflow.model.service.*;
WorkflowManager wm = (WorkflowManager) pluginManager.getBean("workflowManager");
wm.activityVariable(workflowAssignment.getActivityId(),"status", "Approved");
Process Routing Mechanisms
Form Data and Hash Variables for Routing
While workflow variables are essential for process routing, other elements like form data and hash variables can also be used for similar purposes. For example, using a form hash variable in a transition condition e.g., ((# form.Approval_Form.status # === "Approved")) is a viable alternative to check for conditions and make decisions in the process workflow.
Both form hash and workflow hash will work. Apart from routing, a workflow hash can also be used within the application for dynamic data referencing, such as in custom scripts or email bodies, where they can be called upon using syntax like # variable.status #.
Figure 4: Making a routing decision using a Workflow Variable in Process Builder
Figure 5: Making the same routing decision using a Form Hash Variable in Process Builder
For this example, this status field is present in a form named Approval Form. In the above figure, we are simply checking if the value in this form is "Approved" or other than approved ("Rejected"), and then we proceed to route to the correct decision.
Figure 6: Status Field options
A key feature of workflow variables is their ability to create an audit trail. As the process progresses, In the monitor section, the variable list efficiently tracks a record's progress through the workflow.
Figure 7: Viewing a Completed Activity Instance
In this view, one can see the state and statistical data of a particular completed activity instance.
Choosing the Right Tool
The decision to use workflow variables, form data, or hash variables depends on the specific needs of the process. For simpler decision-making where an audit trail is not critical, form data or hash variables might suffice. However, for complex processes where tracking the history of decisions is important, workflow variables become indispensable.
Storage Mechanisms for Form Data Variables and Workflow Variables
Workflow variables in Joget play a crucial role in guiding the process flow and making decisions, but they are different from form data, which users directly input into forms. These workflow variables are not inherently visible in forms or datalists as they operate behind the scenes.
The storage and display of workflow variables pose certain challenges. These variables are stored in the "shkactivitydata" database table. Displaying them in a datalist typically requires an SQL JOIN with this table. However, this can lead to performance issues, particularly in large-scale applications. For example, a process with numerous variables and activities can result in a substantial number of records in the database, escalating rapidly with the number of transactions. This increase in data can significantly impact the performance of datalists. For example, if your process has 10 workflow variables and 10 activities, the total records stored in the DB table is 100 records, and if the total number of process transactions reaches 1,000, you will generate 100,000 records in the "shkactivitydata" table for just one process. If the combined total of processes in all your Joget app is 100 processes, this table will grow to 10 million.
As a best practice, it's recommended to map workflow variables to form fields. This mapping ensures the values of workflow variables are 'copied' to corresponding form fields at each activity, making them visible and accessible for later viewing in forms and datalists. This approach avoids the direct querying of the large "shkactivitydata" table, thereby optimizing performance.