Variable ======== A variable describes the data. Operations ---------- Add variable to View ~~~~~~~~~~~~~~~~~~~~ This operation adds or updates a derived variable in a view for each selected variable. Categorize this variable to another ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This operation adds or overwrites a variable in a view and allows to recode its values. Categorize another variable to this ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This operation maps another variable's values to the current variable categories. Custom derivation ~~~~~~~~~~~~~~~~~ Derive a variable by editing its derivation script manually. Remove ~~~~~~ Removes the variable from the table. Properties ---------- This section displays the proerties of the variable: * Name * Entity Type * Value Type * Repeatable * Unit * Referenced Entity Type * Mime Type * Occurence Group * Index Categories ---------- Some variables can have categories defined. The list of categories is displayed with a summary information: * label (mapped `label` category attribute if this one is defined) * missing (if the category indeicates a missing answer) Edit Categories ~~~~~~~~~~~~~~~ This operation allows the addition, edition abd deletion of a variable's categories. Categories can also be removed or reordered by selecting one or multiple categories. Attributes ---------- Some variables can have attributes defined. The list of attributes is displayed with full information: * namespace * language * value Add Attributes ~~~~~~~~~~~~~~ Thois operation addds a new attribute. The combination of namespace and name must be unique. Edit ~~~~ To assign the attribute to another namespace, change its name or set its value. When editing multiple attributes only the namespace can be modified. Remove ~~~~~~ Remove the attributes. Summary ------- Statistical summary of the variable: * variables with categories: - frequency plot * variables without categories: - histogram - normal probability plot - summary data: N, Min, Max, Mean, Median, etc - frequencies of missiong and non-missing values Script ------ Derived variables (i.e when the table is a view) are persisted in Opal's embedded Version Control System which tracks all changes to a script over time. One practical use case is revising the history of changes and if necessary revert the script to a previous revision. Script History Revisions ~~~~~~~~~~~~~~~~~~~~~~~~ Each time a script is edited a new history revision is created or 'committed' to Opal's version control system. Commit Differences ~~~~~~~~~~~~~~~~~~ Commit revisions are organized in a descending order, i.e., the latest commit at the top of the history stack. A simple 'diff' compares the changes between two immediate commits. Opal also offers a comparison between any revisions to the current revision. Reverting Changes ~~~~~~~~~~~~~~~~~ By editing and saving an older revision, a script content is reverted to its previous version. This operation is tracked as a new revision. Review Commit Differences ~~~~~~~~~~~~~~~~~~~~~~~~~ The commit differences are ordered by the oldest changes first (denoted in red) followed by the latest changes (denoted in green). Values ------ Values can be displayed for a specific identifier or can be filtered to match to certain criteria. Permissions ----------- Specify the access rights to a particular variable and its content View with summary Permission ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Allow the user to see the variable details with its data summary. Does not allow values querying. It induces the read-only access to the parent table and datasource.