DatabaseView
@Target([AnnotationTarget.CLASS, AnnotationTarget.FILE]) class DatabaseView
| androidx.room.DatabaseView |
Marks a class as an SQLite view.
The value of the annotation is a SELECT query used when the view is created.
The class will behave like normal POJO when it is used in a Dao. You can SELECT FROM a DatabaseView similar to an Entity, but you can not INSERT, DELETE or UPDATE into a DatabaseView.
Similar to an Entity, you can use ColumnInfo and Embedded inside to customize the data class.
Example:
@DatabaseView(
"SELECT id, name, release_year FROM Song " +
"WHERE release_year >= 1990 AND release_year <= 1999")
public class SongFrom90s {
long id;
String name;
@ColumnInfo(name = "release_year")
private int releaseYear;
}
Views have to be registered to a RoomDatabase via Database#views.
Summary
| Public constructors | |
|---|---|
|
Marks a class as an SQLite view. |
|
| Properties | |
|---|---|
| String |
The SELECT query. |
| String |
The view name in the SQLite database. |
Public constructors
<init>
DatabaseView(
value: String,
viewName: String)
Marks a class as an SQLite view.
The value of the annotation is a SELECT query used when the view is created.
The class will behave like normal POJO when it is used in a Dao. You can SELECT FROM a DatabaseView similar to an Entity, but you can not INSERT, DELETE or UPDATE into a DatabaseView.
Similar to an Entity, you can use ColumnInfo and Embedded inside to customize the data class.
Example:
@DatabaseView(
"SELECT id, name, release_year FROM Song " +
"WHERE release_year >= 1990 AND release_year <= 1999")
public class SongFrom90s {
long id;
String name;
@ColumnInfo(name = "release_year")
private int releaseYear;
}
Views have to be registered to a RoomDatabase via Database#views.
See Also