> ## Documentation Index
> Fetch the complete documentation index at: https://help.dingtalk.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Physical Columns Supported for Form Data

> In the V4.4.5 product update of October 2023, the YiDA dedicated storage database was upgraded from JSON mode to relational data physical row-column mode. Each form and its component fields map to one or more physical columns, making integration with enterprise data middle platforms and data analysis lakes easier. Up to 1,000 columnar fields are supported.

This upgrade to the YiDA **Dedicated Storage** database applies only to newly created apps within an organization; existing apps are not affected.

The storage of business data collected by forms has been upgraded from JSON mode to a more structured relational physical row-column mode. Using the app as the unit, physical storage columns provide a data storage architecture that is easier to extend and analyze.

For the organization's dedicated storage database, each form is provided with one underlying physical table, and each form component field is provided with one (or more) physical columns. This makes it easier to further integrate the data accumulated by low-code innovative business into enterprise data middle platforms and data analysis lakes.

To enable this feature, please contact your account manager to activate it.

## FAQ

**Q: In physical column mode, each form component corresponds to at least one (or more) physical columns. Is there a maximum limit on the number of fields?**

* The database supports up to 1,000 columnar fields. Once the underlying model exceeds this limit, adding new components to the form will be blocked from saving.

**Q: Which table types does this upgrade cover?**

* Form data. YiDA supports multiple dataset types; this upgrade covers form-filling data in forms and workflow forms.

**Q: Can apps using physical column storage mode be copied?**

* Copying is supported, but the business data storage of the copied app defaults to JSON mode. (Currently, only blank newly created apps support physical column mode. Copy capabilities for existing apps will be gradually enhanced.)

**Q: What is the difference between the tables `yida_entity_instance` and `odin_open_application_data` in the dedicated database? A form instance's data appears in both tables. What is the relationship between them, and by what mechanism is the data kept in sync?**

* `yida_entity_instance` stores the detailed content of form data. All database requests involving data operations within the app are handled by this table. `odin_open_application_data` is used for report display; all report queries and aggregations at the data layer are handled by this table. Currently, both tables are updated simultaneously and are largely consistent in terms of form data storage. However, `yida_entity_instance` contains additional business fields, such as workflow status and version information.