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

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

You can also specify the query as a property getter or function:

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

    @ModelViewQuery @JvmStatic
    fun getQuery() = (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 @Column.

6. Cannot: update, insert, or delete

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

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