modelviews.md

Views

A ModelView is a SQLite representation of a VIEW. Read official SQLite docs here for more information.

As with SQLite a ModelView cannot insert, update, or delete itself as it's read-only. It is a virtual "view" placed on top of a regular table as a prepackaged Select statement. In DBFlow using a ModelView should feel familiar and be very simple.

@ModelView(database = TestDatabase.class)
public class TestModelView {

    @ModelViewQuery
    public static final Query QUERY = SQLite.select().from(TestModel2.class)
            .where(TestModel2_Table.model_order.greaterThan(5));

    @Column
    long model_order;
}

@ModelView(database = TestDatabase::class)
class TestModelView(@Column modelOrder: Long = 0L) {

  companion object {
    @ModelViewQuery @JvmField
    val query = (select from TestModel2::class where TestModel2_Table.model_order.greaterThan(5))
  }
}

To specify the query that a ModelView creates itself with, we must define a public static final field annotated with @ModelViewQuery. This tells DBFlow what field is the query. This query is used only once when the database is created (or updated) to create the view.

The full list of limitations/supported types are: 1. Only @Column/@ColumnMap are allowed 2. No @PrimaryKey or @ForeignKey 3. Supports all fields, and accessibility modifiers that Model support 4. Does not support @InheritedField, @InheritedPrimaryKey 5. Basic, type-converted, non-model @Column. 6. Cannot: update, insert, or delete

ModelView are used identical to Model when retrieving from the database:

SQLite.select()
  .from(TestModelView.class)
  .where(...) // ETC

(select from TestModelView::class where (...))