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@Column

@Column maps a class property to a database column. See Data Columns for the full guide, including the enum/parse/ serialize examples.

function Column(type?: DataType): PropertyDecorator;
function Column(options?: ColumnFieldOptions): PropertyDecorator;
  • @Column(type) — shorthand that only sets dataType.
  • @Column(options) — the full ColumnFieldOptions form.
  • @Column() — every option inferred (see below).
import { Column, DataType, Entity } from '@sqb/connect';

@Entity('customers')
class Customer {
  @Column()
  declare givenName: string;

  @Column(DataType.CHAR)
  declare gender: string;

  @Column({ fieldName: 'birth_date', dataType: DataType.DATE, exclusive: true })
  declare birthDate?: Date;
}

Type inference​

@Column infers type/dataType for you using TypeScript's design-time reflection metadata (Reflect.getMetadata('design:type', ...), which requires emitDecoratorMetadata):

  • If you don't pass type, it's read from the property's declared TS type. If that type is Array, @Column sets type: String, isArray: true instead. If it's another @Entity-decorated class, @Column sets dataType: DataType.JSON automatically (a nested entity stored as a JSON column — different from @Embedded, which spreads a nested object across prefixed sibling columns of the same table).
  • If you don't pass dataType (and none was inferred from a nested-entity type above), it's derived from type (Boolean→BOOL, Number→NUMBER, Date→TIMESTAMP, Array→VARCHAR+isArray: true, Buffer→BINARY, default→VARCHAR).
  • Conversely, passing dataType without type fills type in from the reverse mapping.

@Column sets no other implicit defaults — notNull, length, precision, etc. are left undefined unless specified. See Data Columns → Type inference for the full mapping tables.

Options​

See ColumnFieldOptions for the full field reference (fieldName, dataType, default, isArray, enum, length, precision, scale, collation, autoGenerated, notNull, noUpdate, noInsert, parse, serialize, hidden, exclusive).