> For the complete documentation index, see [llms.txt](https://docs.truedat.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.truedat.io/administration/data-catalog-management.md).
# Data Catalog management
## Systems
As an admin user, you must create the systems in Truedat where metadata from your sources will be loaded.
The only mandatory information for a new system is a name and an `external_id`. You can include additional information by first creating a template named "System" with the "Data Catalog" scope. The example below defines two additional fields: Description and Logo.
Systems can be grouped in the Data Catalog main view. To assign systems to groups, include the following field in the Systems template:
* Name: system\_group
* Widget: Text input
* Type: String
* Cardinality: One or none
Once you have the template, go to **Data Catalog** → **Structures**. In the right-hand menu, click **New System**.
Enter the Name and External ID for the new system. You can also enter the system type to display systems by type. Add any information defined in the template, such as Description or Logo.
## Data Structures Types
As part of Truedat customization, an admin user can configure the following parameters for a structure type:
* Template for additional information. Additional information is metadata that users with permission can enter manually in the application.
* Metadata to display in custom metadata tabs. Select metadata extracted from source systems to display in an additional metadata tab.
* Icon representing the structure type. See [Customise text](/administration/language-management.md) section.
To associate a structure type with a template, provide the following information:
* **Type:** Select the structure type to associate. A list of all structure types in the data catalog is displayed.
* **Default translation:** Define text to display instead of the internal structure type value.
* **Template:** Select the template with the "dd" scope to associate with the structure type. A list of existing templates in that scope is displayed.\
\
You can assign the same template to one or more structure types. Templates are optional. If a structure type has no template, its **Additional information** tab is hidden.
* **Metadata views:** Configure metadata views to display in separate tabs. For each tab, select its name and metadata. If metadata is marked as sensitive during loading, select `_protected` from **Available metadata fields**. All protected metadata is then displayed only to users with permission to view it.
Once registered, you can view the summary and delete existing configurations. Deleting and recreating an association does not delete metadata linked to a structure. Updating an association displays fields from the new template. Saving then stores the new data.
You can select metadata fields for structure searches in the **Filters** field. An admin user must reindex before these fields appear in the structure search screen filter list.
## Data Structures Tags
Use this screen to define the tag types allowed for data structures. You can limit tags to specific domains. This is useful in multi-organization environments. You can create and remove existing tags.
If you delete a tag that is currently used, you are told how many structures use it. You must then confirm the deletion. Removing a tag also removes all its assignments to structures.
## Structure's functional name
Structures can be assigned a functional name in addition to the technical name that is imported from the source.
Create a field named `alias` in the Data Catalog templates. The name must be lowercase. Create a note for a structure and enter the alias. When the note is published, the alias appears in the Data Catalog. The technical name remains visible underneath. Structures without an alias show only the technical name.
## Catalog Views
The default data catalog view groups structures by the system where they were loaded. You can create custom views that group structures by technical or functional metadata, such as processing type or storage type.
To create a view, go to **Catalog Views** and select metadata to group structures. For metadata from Notes, enter the field name, not its label. Technical metadata must be defined as filterable. See [Data Structures Types](#data-structures-types).
A new menu option appears in the Data Catalog module. Create a translation message for the menu option: `sidemenu.metadata.[name of the metadata view]`. Create another message for the catalog view title: `metadata.[name of the metadata view]`.
Create a new catalog view based on technical metadata: "region"
New catalog view: View by Region
## Reference Data Management
This module lets you define reference datasets. These datasets typically contain code values, such as country lists and product codes.
As an admin, you can create reference datasets by uploading a UTF-8 CSV file. The file can be up to 2 MB and contain up to 10 columns. Use a semicolon as the field separator.
You can assign these reference tables to data domains. Users need **View Structures** permission in that domain to view them. You can also use them when defining datasets in quality implementations.