> For the complete documentation index, see [llms.txt](https://docs.tonic.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tonic.ai/app/generation/generators/generator-reference/struct-mask.md). # Struct Mask This is a [composite generator](/app/generation/generators/generator-types/generators-composite.md). Applies selected generators to specific StructFields within a StructType in a Databricks database. For example, for the following StructType: ``` root |-- firstname: string (nullable = true) |-- lastname: string (nullable = true) |-- age: integer (nullable = true) |-- occupation: string (nullable = true) |-- salary: integer (nullable = true) firstname | lastname | age | occupation | salary ------------------------------------------------- John | Smith | 25 | Teacher | 45000 ``` To get the value of the `occupation` field, you would use the expression `root.occupation`. ## Characteristics


Consistency	Determined by the selected sub-generators.
Linking	Determined by the selected sub-generators.
Differential privacy	Determined by the selected sub-generators.
Data-free	Determined by the selected sub-generators.
Allowed for primary keys	No
Allowed for unique columns	No
Uses format-preserving encryption (FPE)	No
Privacy ranking	5
Generator ID (for the API)	`StructMaskGenerator`

## How to configure ### Adding a sub-generator To assign a generator to a path expression: 1. Under **Sub-generators**, click **Add Generator**.\ \ On the sub-generator configuration panel, the **Cell Struct** field contains a sample value from the source database. You can use the previous and next icons to page through different values. 2. In the **Path Expression** field, type the path expression to identify the value to apply the generator to.\ \ **Matched Struct Values** shows the result from the value in **Cell Struct**. 3. From the **Generator Configuration** dropdown list, select the generator to apply to the path expression.\ \ You cannot select another composite generator. 4. Configure the selected generator.\ \ You cannot configure the selected generator to be consistent with another column. 5. To save the configuration and close the add generator panel, click **Save**. ### Managing sub-generators From the **Sub-Generators** list: * To edit a generator assignment, click the edit icon. * To remove a generator assignment, click the delete icon. * To move a generator assignment up or down in the list, click the up or down arrow. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.tonic.ai/app/generation/generators/generator-reference/struct-mask.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.