Module io.helidon.dbclient
Package io.helidon.dbclient

Interface DbColumn

All Known Implementing Classes:
MongoDbColumn
public interface DbColumn
Column data and metadata.

  • Method Summary

    Modifier and Type
    Method
    Description
    <T> T
    as(GenericType<T> type)
    Value of this column as a generic type.
    <T> T
    as(Class<T> type)
    Typed value of this column.
    String
    dbType()
    Type of the column in the language of the database.
    Class<?>
    javaType()
    Type of the column as would be returned by the underlying database driver.
    String
    name()
    Column name.
    default Optional<Integer>
    precision()
    Precision of this column.
    default Optional<Integer>
    scale()
    Scale of this column.
    default Object
    value()
    Untyped value of this column, returns java type as provided by the underlying database driver.

  • Method Details

    • as

      <T> T as(Class<T> type) throws MapperException
      Typed value of this column. This method can return a correct result only if the type is the same as javaType() or there is a Mapper registered that can map it.
      Type Parameters:
      T - type of the returned value
      Parameters:
      type - class of the type that should be returned (must be supported by the underlying data type)
      Returns:
      value of this column correctly typed
      Throws:
      MapperException - in case the type is not the underlying javaType() and there is no mapper registered for it

    • as

      <T> T as(GenericType<T> type) throws MapperException
      Value of this column as a generic type. This method can return a correct result only if the type represents a class, or if there is a Mapper registered that can map underlying javaType() to the type requested.
      Type Parameters:
      T - type of the returned value
      Parameters:
      type - requested type
      Returns:
      value mapped to the expected type if possible
      Throws:
      MapperException - in case the mapping cannot be done

    • value

      default Object value()
      Untyped value of this column, returns java type as provided by the underlying database driver.
      Returns:
      value of this column

    • javaType

      Class<?> javaType()
      Type of the column as would be returned by the underlying database driver.
      Returns:
      class of the type
      See Also:

    • dbType

      String dbType()
      Type of the column in the language of the database.

      Example for SQL - if a column is declared as VARCHAR(256) in the database, this method would return VARCHAR and method javaType() would return String.

      Returns:
      column type as the database understands it

    • name

      String name()
      Column name.
      Returns:
      name of this column

    • precision

      default Optional<Integer> precision()
      Precision of this column.

      Precision depends on data type:

      • Numeric: The maximal number of digits of the number
      • String/Character: The maximal length
      • Binary: The maximal number of bytes
      • Other: Implementation specific
      Returns:
      precision of this column or empty if precision is not available

    • scale

      default Optional<Integer> scale()
      Scale of this column.

      Scale is the number of digits in a decimal number to the right of the decimal separator.

      Returns:
      scale of this column or empty if scale is not available