Plan and Prepare Data Connections22% of the exam
ISMEMBEROF, USERNAME and other user functions
Tell the group function ISMEMBEROF apart from the user functions USERNAME, FULLNAME, ISUSERNAME, ISFULLNAME and USERDOMAIN, know their literal-string, encoding, sign-in and session rules, and choose a group-based or data-driven security rule.
Identify group functions versus user functions.
~7 min read · 8 practice questions ·
What the exam expects
- Identify ISMEMBEROF as the group function and USERNAME, FULLNAME, ISUSERNAME, ISFULLNAME and USERDOMAIN as user functions, with what each returns.
- Apply the rules that break group tests: literal-string arguments, HTML URL encoding of special characters, NULL when not signed in, new sessions after membership changes.
- Predict which rows a filter that combines a user comparison and a group test keeps for a given person.
- Recommend a group-based rule or a data-driven USERNAME() comparison from how access is managed and how many groups it needs.
Key terms:
- Group function: ISMEMBEROF, which tests membership in a Tableau group.
- User function: a function that returns or tests the signed-in user's own identity, such as USERNAME().
- Literal string: a value typed in quotes in the calculation, not a field reference.
- User filter: a calculated field such as
[Username field] = USERNAME()used as a filter so people see only their data. - Session: a user's visit to a workbook or view; group changes apply from the next one.
Key facts
ISMEMBEROF output
- Detail
- TRUE, FALSE, or NULL when not signed in
Membership source
- Detail
- Tableau groups on Tableau Cloud or Tableau Server
Arguments of ISMEMBEROF, ISUSERNAME, ISFULLNAME
- Detail
- Literal strings, not fields
Special characters
- Detail
- HTML URL encoding; _ ( ) ! permitted unencoded
"All Users"
- Detail
- ISMEMBEROF returns TRUE
Membership change
- Detail
- Seen in a new session; existing session is stale
USERNAME() in Desktop
- Detail
- Local or network username
True option for a user filter in Desktop
- Detail
- Visible only after signing in to Server or Cloud
Dynamic user filter
- Detail
- Needs the security information in the data
Sources for this section (2)
- Why can a USERNAME() filter behave differently in Tableau Desktop than on the site?
- Which special characters can appear in a group name passed to ISMEMBEROF without HTML URL encoding?
- Why does appending OR ISMEMBEROF('All Users') to a filter open the data to everyone?
- What does ISFULLNAME("Hamlin Myrer") return for a signed-in user whose full name is different?
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