# Check for and resolve schema changes {% hint style="info" %} Included in the Basic API. {% endhint %} Before you start a data generation job, we recommend that you check for and resolve any schema changes on the source database. In the Tonic Structural application, you can use the [Schema Changes view](https://docs.tonic.ai/app/generation/schema-changes) to review and resolve any changes. From the API, you can: * Retrieve a list of schema changes * Resolve schema changes ## Retrieve the list of schema changes To view the list of schema changes, use [**GET**** /api/SchemaDiff**](https://app.tonic.ai/apidocs/index.html#/SchemaDiff/GetSchemaDiffs). In the results, each schema change uses the following format: ```json { "schemaName": "string", "tableName": "string", "issueCode": "string", "columnName": "string", "pathName": "string", "oldDataType": "string", "newDataType": "string" } ``` Where:


`schemaName`	The name of the affected schema.
`tableName`	The name of the affected table. For MongoDB, this is the name of the affected collection.
`issueCode`	The type of schema change. Possible values are: `new_column` - The column was added to the table. `changed_column_type` - The column data type changed. Data type changes are only listed if the change introduces a conflict in the workspace configuration. `new_table` - The table was added to the schema. `missing_column` - The column was removed from the table. Removed columns are only listed if the removal introduces a conflict in the workspace configuration. `missing_table` - The table was removed from the schema. Removed tables are only listed if the removal introduces a conflict in the workspace configuration. `changed_nullability` - The column changed whether it can be NULL. Nullability changes are only listed if the change introduces a conflict in the workspace configuration. `new_foreign_key` - The column had an assigned generator, but is now a foreign key. Foreign keys must inherit the generator from the primary key. `new_collection` - For MongoDB and Amazon DynamoDB only. The collection was added to the source database. `missing_collection` - For MongoDB and Amazon DynamoDB only. The collection was removed from the source database. Removed collections are only listed if the change introduces a conflict in the workspace configuration. `new_path_type` - For MongoDB, Amazon DynamoDB, and JSON fields only. The column has a new path type. `missing_path_type` - For MongoDB, Amazon DynamoDB, and JSON fields only. The column path type was removed.
`columnName`	The name of the affected column. For new or removed tables or collections, there is no column name.
`pathName`	The affected path. For JSON fields only, for `new_path_type` and `missing_path_type` issues.
`oldDataType`	For columns that change type, the previous data type.
`newDataType`	For a new column, the data type of the column. For columns that change type, the new data type.

## Resolve selected schema changes You can use the API to resolve specified schema changes. When you use the API to resolve schema changes: * For information on how Structural resolves sensitive schema changes (new tables and columns), go to [#schema-changes-resolve-conflicting](https://docs.tonic.ai/app/generation/schema-changes#schema-changes-resolve-conflicting "mention"). * For information on how Structural resolves notifications (removed tables and columns), go to [#schema-changes-dismiss-non-conflicting](https://docs.tonic.ai/app/generation/schema-changes#schema-changes-dismiss-non-conflicting "mention"). To resolve a single schema change, use [**POST**** /api/SchemaDiff/resolve**](https://app.tonic.ai/apidocs/index.html#/SchemaDiff/Resolve). The request body provides the details for a single schema change. To resolve multiple changes, use [**POST**** /api/SchemaDiff/resolve\_multiple**](https://app.tonic.ai/apidocs/index.html#/SchemaDiff/ResolveMultiple). The request body provides the details for each schema change. In the request body, each schema change has the following format: ```json { "workspaceId": "string", "issueCode": "new_column", "schemaName": "string", "tableName": "string", "columnName": "string", "pathName": "string", "dataType": "string" } ``` Where:


`workspaceId`	The identifier of the workspace.
`issueCode`	The type of issue.
`schemaName`	The name of the affected schema.
`tableName`	The name of the affected table.
`columnName`	The name of the affected column. Only provided for column-specific issues.
`pathName`	For JSON fields only. The affected path. Provided for path-specific issues.
`dataType`	For MongoDB, Amazon DynamoDB, and JSON fields only. The data type for the affected column.

## Resolving all schema changes for a workspace To resolve all schema changes for a workspace, use: [**POST**** /api/SchemaDiff/{workspaceId}/resolve\_all**](https://app.tonic.ai/apidocs/index.html#/SchemaDiff/ResolveAll) The `resolutionOption` parameter identifies the types of schema changes to resolve. The options are: * `All` - Indicates to resolve all of the schema changes. * `Actions` - Indicates to only resolve sensitive schema changes. * `Notifications` - Indicates to only resolve notifications.