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

Interface DbColumn

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

    • Method Detail

      • 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()

      • 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