Applying schema changes involves several steps. First, you need to compare the replica schemas to find differences. This process produces a replica schema changes file. This file can then be imported to apply the changes.
In a connected environment, follow the "Compare replica schema" steps below to see how to compare replicas and the "Import a replica schema" steps below to see how to import the changes. In a disconnected environment, before you can compare replica schemas, you first need to export the schema to a file and send it to the relative replica for comparison and import. See the "Export a replica schema" steps below to see how to do this.
Note that you can run the import wizard to see the differences and then exit without applying changes. The wizard also allows you to choose to apply only some of the schema changes.
The Export Replica Schema command is used to export the schema to an XML workspace document. The workspace document includes the schema for all data in the replica.
You can export a replica schema by opening the Export Replica Schema wizard from the geodatabase or geodata server pull-right menu in ArcCatalog or from the Distributed Geodatabase toolbar in ArcMap.
The Export Replica Schema command has a combo box that allows you to choose the replica to export. The combo box will list both parent and child replicas. For one-way replicas, only the parent replica can export schema, while for checkout replicas, only the child replica can export schema.
How to export a replica schema
- In ArcCatalog, right-click your geodatabase, point to Distributed Geodatabases, and click Export Replica Schema. Right-click geodata services published through ArcGIS Server to access remote geodatabases.
- In ArcMap, click the Export Replica Schema button on the Distributed Geodatabase toolbar. Remote geodatabases are accessed in ArcMap through map services that have the geodata access capability enabled.
- Specify a name for the XML file that is to be created.
- Choose the replica to export and click Finish.
The Compare Replica Schema command is used to compare your replica schema with a relative replica and output the replica schema changes as an XML workspace document.
How to compare replica schema
- In ArcCatalog, right-click your geodatabase connection, point to Distributed Geodatabases,and click Compare Replica Schema. Right-click geodata services published through ArcGIS Server to access remote geodatabases.
- In ArcMap, click the Compare Replica Schema button on the Distributed Geodatabase toolbar. Remote geodatabases are accessed in ArcMap through map services that have the geodata access capability enabled.
- Specify or browse for the schema in either a relative geodatabase or, in the disconnected case, the replica schema file for the relative replica. The geodatabase may be local or remote.
- Use the Replica name combo box to choose the replica.
- Specify or browse for an output replica schema changes XML file and click Finish.
The Import Replica Schema command lists schema differences and allows you to apply the changes to match the relative replica.
The second panel of the Import Replica Schema Wizard reports the schema changes in the following columns:
- Apply—The check box along the left side allows you to choose whether or not you want to apply the changes.
- Data—The data where schema differences were detected.
- Change—The type of schema change to be applied to match the relatives replica. For example, if the delta file had one more field than the replica, it would list the change as Add Field.
- Details—The actual schema to be changed, for example, the name of the field to be added or deleted.
One row is listed per schema difference. For example, if two new fields were added to the same table, this table is listed two times. This list is also sortable so you can quickly separate the additions from the deletions.
The default is to perform a union of the schema changes between the two replicas. This means that, by default, delete operations are checked off and add operations are checked on. This way, performing a default schema synchronization will not result in a loss of data.
Schema changes can be listed in two different ways:
Optional—Optional schema changes appear with the Apply check box enabled. You can decide whether to apply the change.
Can't Apply—Schema changes that can't be applied are listed with the Apply check box unchecked and grayed out. The purpose of listing the schema change is to alert you to the difference. An example is a case where the replica importing the schema has deleted a topology that still exists on the relative. This is a valid schema difference, but since rebuilding a topology requires unversioning the data, it can't be applied.
Some changes can be applied to individual replica geodatabases but have no effect on data synchronization. For example, adding or removing an attribute index is not detected or even synchronized during schema synchronization. A replica may have indexes that the relative replica doesn't have, but since data synchronization is not affected, this difference is ignored.
How to import a replica schema
- In ArcCatalog, right-click your geodatabase connection, point to Distributed Geodatabases, and click Import Replica Schema. Right-click geodata services published through ArcGIS Server to access remote geodatabases.
- In ArcMap, click the Import Replica Schema button on the Distributed Geodatabase toolbar. Remote geodatabases are accessed in ArcMap through map services that have the geodata access capability enabled.
- Browse for the replica schema changes file.
- Use the combo box to select the replica schema to import and click Next.
- The second dialog box lists the differences between the two schemas. Check the check boxes under the Apply column for the changes you want to apply to the replica schema.
- Click Finish.
