index

Documentation

Index

• Variables
• type Index
  • func New(tx engine.Transaction, idxName string, opts Options) *Index
  • func (idx *Index) AscendGreaterOrEqual(pivot document.Value, fn func(val, key []byte, isEqual bool) error) error
  • func (idx *Index) Delete(v document.Value, k []byte) error
  • func (idx *Index) DescendLessOrEqual(pivot document.Value, fn func(val, key []byte, isEqual bool) error) error
  • func (idx *Index) EncodeValue(v document.Value) ([]byte, error)
  • func (idx *Index) Set(v document.Value, k []byte) error
  • func (idx *Index) Truncate() error
• type Options

Variables

var (
	// ErrDuplicate is returned when a value is already associated with a key
	ErrDuplicate = errors.New("duplicate")
)

Types

type Index

type Index struct {
	Unique bool
	Type   document.ValueType
	// contains filtered or unexported fields
}

An Index associates encoded values with keys. It is sorted by value following the lexicographic order.

func New

func New(tx engine.Transaction, idxName string, opts Options) *Index

New creates an index that associates a value with a list of keys.

func (*Index) AscendGreaterOrEqual

func (idx *Index) AscendGreaterOrEqual(pivot document.Value, fn func(val, key []byte, isEqual bool) error) error

AscendGreaterOrEqual seeks for the pivot and then goes through all the subsequent key value pairs in increasing order and calls the given function for each pair. If the given function returns an error, the iteration stops and returns that error. If the pivot is empty, starts from the beginning.

func (*Index) Delete

func (idx *Index) Delete(v document.Value, k []byte) error

Delete all the references to the key from the index.

func (*Index) DescendLessOrEqual

func (idx *Index) DescendLessOrEqual(pivot document.Value, fn func(val, key []byte, isEqual bool) error) error

DescendLessOrEqual seeks for the pivot and then goes through all the subsequent key value pairs in descreasing order and calls the given function for each pair. If the given function returns an error, the iteration stops and returns that error. If the pivot is empty, starts from the end.

func (*Index) EncodeValue

func (idx *Index) EncodeValue(v document.Value) ([]byte, error)

EncodeValue encodes the value we are going to use as a key, If the index is typed, encode the value without expecting the presence of other types. Ff not, encode so that order is preserved regardless of the type.

func (*Index) Set

func (idx *Index) Set(v document.Value, k []byte) error

Set associates a value with a key. If Unique is set to false, it is possible to associate multiple keys for the same value but a key can be associated to only one value.

func (*Index) Truncate

func (idx *Index) Truncate() error

Truncate deletes all the index data.

type Options

type Options struct {
	Unique bool

	// If specified, the indexed expects only one type.
	Type document.ValueType
}

Options of the index.