String name: The column name. Defaults to the field name.

String columnDefinition: The database-specific column type name. This property is only used by vendors that support creating tables from your mapping metadata. During table creation, the vendor will use the value of the columnDefinition as the declared column type. If no columnDefinition is given, the vendor will choose an appropriate default based on the field type combined with the column's length, precision, and scale.

int length: The column length. This property is typically only used during table creation, though some vendors might use it to validate data before flushing. CHAR and VARCHAR columns typically default to a length of 255; other column types use the database default.

int precision: The precision of a numeric column. This property is often used in conjunction with scale to form the proper column type name during table creation.

int scale: The number of decimal digits a numeric column can hold. This property is often used in conjunction with precision to form the proper column type name during table creation.

boolean nullable: Whether the column can store null values. Vendors may use this property both for table creation and at runtime; however, it is never required. Defaults to true.

boolean insertable: By setting this property to false, you can omit the column from SQL INSERT statements. Defaults to true.

boolean updatable: By setting this property to false, you can omit the column from SQL UPDATE statements. Defaults to true.

String table: Sometimes you will need to map fields to tables other than the primary table. This property allows you specify that the column resides in a secondary table. We will see how to map fields to secondary tables later in the chapter.

name

column-definition

length

precision

scale

insertable

updatable

table