Client and backend. This class is shared: the same code is compiled into your app and into your server, so everything on this page works in both.

@Retention(CLASS) @Target({FIELD})

public @interface Column

Renames or constrains an @Entity field’s column. Optional – when absent, the column name defaults to the field name and the type is inferred from the Java field type (String -> TEXT, int/long -> INTEGER, float/double -> REAL, boolean -> INTEGER, byte[] -> BLOB, java.util.Date -> INTEGER).

Methods

`public abstract` `String name() default ""`	Column name.
`public abstract boolean nullable() default true`	When false the column gets a `NOT NULL` constraint at table-create time.
`public abstract boolean unique() default false`	Creates a unique index when the managed schema is created.
`public abstract` `String type() default ""`	Optional explicit SQL type.

Method details

name

public abstract String name() default ""

Column name. Defaults to the field name when blank.

nullable

public abstract boolean nullable() default true

When false the column gets a NOT NULL constraint at table-create time.

unique

public abstract boolean unique() default false

Creates a unique index when the managed schema is created.

type

public abstract String type() default ""

Optional explicit SQL type. Use the SQLite type names (TEXT, INTEGER, REAL, BLOB, NUMERIC). When blank the processor infers the type from the field’s Java type.

On the backend the value is written through to the CREATE TABLE unchanged, so it is engine specific by construction: a type only PostgreSQL understands makes the entity PostgreSQL-only. Leaving it blank keeps the entity portable, because the dialect then names the type each engine spells differently (TEXT/VARCHAR, REAL/DOUBLE PRECISION, BLOB/BYTEA).