# Views

A `ModelView` is a SQLite representation of a `VIEW`. Read official SQLite docs [here](https://www.sqlite.org/lang_createview.html) 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.

```kotlin
@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:

```kotlin
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:

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