Saving Data on Android

INTEGER
, or 
Int
 in Kotlin.
@ColumnInfo
In the same way that the 
tableName
 property of the 
@Entity
 annotation allows you 
to customize the name of your table, the 
@ColumnInfo
 annotation lets you change 
the name of your columns — class properties in Kotlin:
@Entity
 
data
 
class
 
Movie
( 
    
@PrimaryKey(autogenerate = true)
 
var
 id: 
Int
, 
    
var
 title: String?, 
    
var
 description: String?, 
    
@ColumnInfo(name = "release_date")
 
var
 releaseDate: String?, 
    
var
 rating: 
Float
 
)
Saving Data on Android
Chapter 6: Entity Definitions
raywenderlich.com
109

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This annotation is particularly useful because you will often want to follow different 
naming conventions for your class properties and your database columns, such as 
releaseDate
 vs 
release_date
 naming.
@Ignore
Room translates all of your class properties into database columns by default. If 
there is a field that you don't want to be converted into a column, you can use the 
@Ignore
 annotation to tell Room to ignore it:
@Entity
 
data
 
class
 
Movie
( 
    
@PrimaryKey(autogenerate = true)
 
var
 id: 
Int
, 
    
var
 title: String?, 
    
var
 description: String?, 
    
@ColumnInfo(name = "release_date")
 
var
 releaseDate: String?, 
    
var
 rating: 
Float
, 
    
@Ignore
 
var
 poster: Bitmap? 
)
In the above code, you use the 
@Ignore
 annotation to tell Room that you don't want 
the 
poster
 field to be converted as a column in your Movie table. You can also use 
the 
ignoredColumn
 property of the 
@Entity
 annotation to declare which fields you 
want to ignore:
@Entity(ignoredColumns = arrayOf("poster")
) 
data
 
class
 
Movie
( 
    
@PrimaryKey(autogenerate = true)
 
var
 id: 
Int
, 
    
var
 title: String?, 
    
var
 description: String?, 
    
@ColumnInfo(name = "release_date")
 
var
 releaseDate: String?, 
    
var
 rating: 
Float
, 
    
var
 poster: Bitmap? 
)