ColumnInfo

BINARY

static val BINARY: Int

Collation sequence for case-sensitive match.

Value: 2

BLOB

static val BLOB: Int

Column affinity constant for binary data.

Value: 5

INHERIT_FIELD_NAME

static val INHERIT_FIELD_NAME: String

Constant to let Room inherit the field name as the column name. If used, Room will use the field name as the column name.

Value: "[field-name]"

INTEGER

static val INTEGER: Int

Column affinity constant for integers or booleans.

Value: 3

LOCALIZED

static val LOCALIZED: Int

Collation sequence that uses system's current locale.

Value: 5

NOCASE

static val NOCASE: Int

Collation sequence for case-insensitive match.

Value: 3

REAL

static val REAL: Int

Column affinity constant for floats or doubles.

Value: 4

RTRIM

static val RTRIM: Int

Collation sequence for case-sensitive match except that trailing space characters are ignored.

Value: 4

TEXT

static val TEXT: Int

Column affinity constant for strings.

Value: 2

UNDEFINED

static val UNDEFINED: Int

Undefined type affinity. Will be resolved based on the type.

Value: 1

UNICODE

static val UNICODE: Int

Collation sequence that uses Unicode Collation Algorithm.

Value: 6

UNSPECIFIED

static val UNSPECIFIED: Int

Collation sequence is not specified. The match will behave like BINARY.

Value: 1

VALUE_UNSPECIFIED

static val VALUE_UNSPECIFIED: String

A constant for defaultValue() that makes the column to have no default value.

Value: "[value-unspecified]"

<init>

ColumnInfo(
    name: String, 
    typeAffinity: Int, 
    index: Boolean, 
    collate: Int, 
    defaultValue: String)

Allows specific customization about the column associated with this field.

For example, you can specify a column name for the field or change the column's type affinity.

collate

val collate: Int

The collation sequence for the column, which will be used when constructing the database.

The default value is UNSPECIFIED. In that case, Room does not add any collation sequence to the column, and SQLite treats it like BINARY.

defaultValue

val defaultValue: String

The default value for this column.

@ColumnInfo(defaultValue = "No name")
        public String name;
     
       @ColumnInfo(defaultValue = "0")
        public int flag;
      

Note that the default value you specify here will NOT be used if you simply insert the Entity with @Insert. In that case, any value assigned in Java/Kotlin will be used. Use @Query with an INSERT statement and skip this column there in order to use this default value.

NULL, CURRENT_TIMESTAMP and other SQLite constant values are interpreted as such. If you want to use them as strings for some reason, surround them with single-quotes.

@ColumnInfo(defaultValue = "NULL")
        @Nullable
        public String description;
     
        @ColumnInfo(defaultValue = "'NULL'")
        @NonNull
        public String name;
      

You can also use constant expressions by surrounding them with parentheses.

@CoumnInfo(defaultValue = "('Created at' || CURRENT_TIMESTAMP)")
        public String notice;
      

index

val index: Boolean

Convenience method to index the field.

If you would like to create a composite index instead, see: Index.

name

val name: String

Name of the column in the database. Defaults to the field name if not set.

typeAffinity

val typeAffinity: Int

The type affinity for the column, which will be used when constructing the database.

If it is not specified, the value defaults to UNDEFINED and Room resolves it based on the field's type and available TypeConverters.

See SQLite types documentation for details.