# Compare schemas

**Compare Schemas** is a utility provided by ONEWEB that allows users to **compare two versions of a database schema** designed in **Data Designer**.

This tool helps teams track structural changes in the data model over time and understand differences between schema versions before deployment or migration.

The utility is available from the **Tools** section in the **Database Tools** menu within AppSpace.

***

### Access the Compare Schema Tool

To open the schema comparison utility:

1. Navigate to **AppSpace**
2. Open **Database Tools**
3. Go to the **Tools** section
4. Select **Compare Schemas**

<figure><img src="https://2015371994-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FMpDjHWFRUtZ5nJcSfVXd%2Fuploads%2FwLvzBhjVYYicS9Q0i0g1%2Fimage.png?alt=media&#x26;token=484938d8-ec79-4a49-b077-4d4edef80410" alt=""><figcaption></figcaption></figure>

***

### Create a New Schema Comparison

Inside the Compare Schema utility, users can initiate a new comparison by selecting:

* **Source ER Diagram**
* **Source Version**
* **Target ER Diagram**
* **Target Version**

This setup allows comparison between:

* Different versions of the same data model, or
* Two different ER Diagrams altogether

<figure><img src="https://2015371994-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FMpDjHWFRUtZ5nJcSfVXd%2Fuploads%2FO7CZyXa4h4Uis3Iep3bU%2Fimage.png?alt=media&#x26;token=19096ddf-a8df-46d3-b6da-039995e49b65" alt=""><figcaption></figcaption></figure>

***

### View Comparison Results

After executing the comparison, ONEWEB displays the **Schema Comparison Analysis** screen.

This screen highlights differences such as:

* Added or removed entities (tables)
* Modified columns or data types
* Changes in primary keys or constraints
* Structural differences across versions

<figure><img src="https://2015371994-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FMpDjHWFRUtZ5nJcSfVXd%2Fuploads%2FrC4Ksmi3AhmpLHNC81Ej%2Fimage.png?alt=media&#x26;token=90047aca-b9f7-4b7a-94d7-a10ff1ca6a25" alt=""><figcaption></figcaption></figure>

The analysis helps users identify exactly how the schema has evolved.

***

### Use Cases for Schema Comparison

The Compare Schemas tool is commonly used for:

* Reviewing changes before applying schema updates
* Validating data model changes across versions
* Supporting controlled schema evolution
* Reducing risk during database migration or release
* Aligning development and production schemas

***

### Summary

**Compare Schemas** provides a reliable way to track and analyze changes in database designs created with **Data Designer**.

With this utility, teams can:

* Compare schema versions visually
* Identify structural differences accurately
* Validate data model evolution
* Support safer and more controlled deployments

This tool plays a key role in maintaining **data integrity and governance** within ONEWEB’s low‑code development lifecycle.


---

# Agent Instructions: 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:

```
GET https://docs.onewebstack.com/designer-reference/data-designer/compare-schemas.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.