Virtual Fields (@Transient)
Fields annotated with JPA @Transient will not generate a database column at startup — they are purely a UI display mechanism. Use DataProxy to populate or consume virtual field values.
Virtual Columns
Display a non-database field in the table and populate its value via DataProxy.afterFetch:
java
@Erupt(name = "Virtual Column", dataProxy = VirtualDemo.class)
@Table(name = "virtual_demo")
@Entity
public class VirtualDemo extends BaseModel implements DataProxy<VirtualDemo> {
// Text input
@EruptField(
views = @View(title = "Text"),
edit = @Edit(title = "Text")
)
private String field;
@Transient
@EruptField(
views = @View(title = "Virtual Column (non-database field)")
)
private String virtualColumn;
@Override
public void afterFetch(Collection<Map<String, Object>> list) {
for (Map<String, Object> map : list) {
map.put("virtualColumn", "Custom virtual column value");
}
}
}Virtual Form Fields
Show a non-database field in the form and consume its value in DataProxy after submission:
java
@Erupt(name = "Virtual Form", dataProxy = VirtualDemo.class)
@Table(name = "virtual_demo")
@Entity
@Setter
public class VirtualDemo extends BaseModel implements DataProxy<VirtualDemo> {
@EruptField(
views = @View(title = "Text"),
edit = @Edit(title = "Text")
)
private String text;
@Transient
@EruptField(
edit = @Edit(title = "Virtual Form Field")
)
private String virtualForm;
@Override
public void afterAdd(VirtualDemo virtualDemo) {
// Combine the virtual field value into the persisted field on add
this.text = this.text + this.virtualForm;
}
}Contributors
YuePeng
Claude Opus 5 (1M context)