sod

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 Go to latest Published: Oct 11, 2021 License: GPL-3.0 Imports: 14 Imported by: 0

README

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Go Simple Object Database

A simple database model to store Go structure (on disk) and search across them. It has features close to what an ORM framework can provide but has the advantage of being:

  • in pure Go (de facto portable)
  • does not depend on any DB engine (SQL, SQLite, Mongo ...) to do its job
  • everything is kept simple (one file per structure and eventually an index) It supports structure fields indexing to speed up searches on important fields.

What you should use this project for:

  • you want to implement Go struct persistency in a simple way
  • you want to be able to DB engine like operations on those structures (Update, Delete, Search ...)
  • you don't want to deploy an ORM framework

What you should not use this project for:

  • even though performances are not so bad, I don't think you can rely on it for high troughput DB operations

Examples

See examples directory for all examples.

Documentation

Index

Constants

View Source 
const (
	SchemaFilename = "schema.json"
)

Variables

View Source 
var (
	ErrUnkownField          = errors.New("unknown object field")
	ErrFieldNotIndexed      = errors.New("field not indexed")
	ErrFieldUnique          = errors.New("unique constraint on field")
	ErrUnkownSearchOperator = errors.New("unknown search operator")
)
View Source 
var (
	ErrBadSchema       = errors.New("schema must be a file")
	ErrMissingObjIndex = errors.New("schema is missing object index")

	DefaultSchema = Schema{Extension: ".json"}
)
View Source 
var (
	DefaultPermissions = fs.FileMode(0700)
	LowercaseNames     = true
)
View Source 
var (
	ErrEOI = errors.New("end of iterator")
)
View Source 
var (
	ErrNoObjectFound = errors.New("no object found")
)
View Source 
var (
	ErrUnknownKeyType = errors.New("unknown key type")
)

Functions

func IsNoObjectFound added in v1.3.0 

func IsNoObjectFound(err error) bool

func IsUnique added in v1.3.0 

func IsUnique(err error) bool

func NewFieldIndex 

func NewFieldIndex(desc FieldDescriptor, opts ...int) *fieldIndex

NewFieldIndex returns an empty initialized slice. Opts takes len and cap in order to initialize the underlying slice

func UnmarshalJsonFile 

func UnmarshalJsonFile(path string, i interface{}) (err error)

Types

type DB 

type DB struct {
	sync.RWMutex
	// contains filtered or unexported fields
}

func Open 

func Open(root string) *DB

Open opens a Simple Object Database

func (*DB) All 

func (db *DB) All(of Object) (out []Object, err error)

All returns all Objects in the DB

func (*DB) Close 

func (db *DB) Close() (last error)

func (*DB) Commit 

func (db *DB) Commit(o Object) (err error)

Commit object schema on the disk. This method must be called after Insert/Delete operations.

func (*DB) Count 

func (db *DB) Count(of Object) (n int, err error)

Count the number of Object in the database

func (*DB) Create 

func (db *DB) Create(o Object, s Schema) (err error)

Create a schema for an Object

func (*DB) Delete 

func (db *DB) Delete(o Object) (err error)

Delete deletes a single Object from the database. If object is indexed DB must be committed to make the changes of the index persistent

func (*DB) DeleteAll 

func (db *DB) DeleteAll(of Object) (err error)

DeleteAll deletes all Objects of the same type. If object is indexed, DB must be committed to make the changes of the index persistent

func (*DB) Drop 

func (db *DB) Drop() (err error)

Drop drops all the database

func (*DB) Exist 

func (db *DB) Exist(o Object) (ok bool, err error)

Exist returns true if the object exist.

func (*DB) Get 

func (db *DB) Get(o Object) (err error)

Get gets a single Object from the DB

func (*DB) InsertOrUpdate 

func (db *DB) InsertOrUpdate(o Object) (err error)

InsertOrUpdate inserts or updates a single Object and commits changes. This method is not suited for bulk insertions as each insert will trigger a write overhead. For bulk insertion use InsertOrUpdateBulk function

func (*DB) InsertOrUpdateBulk 

func (db *DB) InsertOrUpdateBulk(in chan Object) (err error)

InsertOrUpdateBulk inserts objects in bulk in the DB. This function is locking the DB and will terminate only when input channel is closed

func (*DB) Iterator 

func (db *DB) Iterator(of Object) (it *Iterator, err error)

Iterator returns an Object Iterator

func (*DB) Schema 

func (db *DB) Schema(of Object) (s *Schema, err error)

Schema retrieves the schema of an Object

func (*DB) Search 

func (db *DB) Search(o Object, field, operator string, value interface{}) *Search

Search Object where field matches value according to an operator

type FieldDescriptor added in v1.3.0 

type FieldDescriptor struct {
	Name   string
	Index  bool
	Unique bool
}

type Index 

type Index struct {
	Fields map[string]*fieldIndex
	// mapping ObjectId -> Object UUID
	ObjectIds map[uint64]string
	// contains filtered or unexported fields
}

func NewIndex 

func NewIndex(fields ...FieldDescriptor) *Index

func (*Index) Delete 

func (in *Index) Delete(o Object)

func (*Index) InsertOrUpdate 

func (in *Index) InsertOrUpdate(o Object) (err error)

func (*Index) Len 

func (in *Index) Len() int

func (*Index) MarshalJSON 

func (in *Index) MarshalJSON() ([]byte, error)

func (*Index) Search 

func (in *Index) Search(o Object, field string, operator string, value interface{}, constrain []*IndexedField) ([]*IndexedField, error)

func (*Index) UnmarshalJSON 

func (in *Index) UnmarshalJSON(data []byte) error

type IndexedField 

type IndexedField struct {
	// the value we want to index
	Value interface{}
	// the ObjectId of the object in the list of object
	// it must be unique accross one ObjectId
	ObjectId uint64
}

func NewIndexedField 

func NewIndexedField(value interface{}, objid uint64) (*IndexedField, error)

func (*IndexedField) DeepEqual 

func (f *IndexedField) DeepEqual(other *IndexedField) bool

func (*IndexedField) Equal 

func (f *IndexedField) Equal(other *IndexedField) bool

func (*IndexedField) Evaluate 

func (f *IndexedField) Evaluate(operator string, other *IndexedField) bool

func (*IndexedField) Greater 

func (f *IndexedField) Greater(other *IndexedField) bool

func (*IndexedField) Less 

func (f *IndexedField) Less(other *IndexedField) bool

func (*IndexedField) MarshalJSON 

func (f *IndexedField) MarshalJSON() ([]byte, error)

func (*IndexedField) String 

func (f *IndexedField) String() string

func (*IndexedField) UnmarshalJSON 

func (f *IndexedField) UnmarshalJSON(data []byte) error

func (*IndexedField) ValueTypeFromString 

func (f *IndexedField) ValueTypeFromString(t string)

func (*IndexedField) ValueTypeString 

func (f *IndexedField) ValueTypeString() string

type Item 

type Item struct {
	// contains filtered or unexported fields
}

func (*Item) Initialize 

func (o *Item) Initialize(uuid string)

func (*Item) UUID 

func (o *Item) UUID() string

type Iterator 

type Iterator struct {
	// contains filtered or unexported fields
}

func (*Iterator) Len 

func (it *Iterator) Len() int

func (*Iterator) Next 

func (it *Iterator) Next() (o Object, err error)

func (*Iterator) Reverse added in v1.2.0 

func (it *Iterator) Reverse() *Iterator

type Object 

type Object interface {
	UUID() string
	Initialize(string)
}

type Schema 

type Schema struct {
	Extension    string `json:"extension"`
	ObjectsIndex *Index `json:"index"`
	// contains filtered or unexported fields
}

func (*Schema) Index 

func (s *Schema) Index(o Object) error

func (*Schema) Initialize 

func (s *Schema) Initialize(o Object)

func (*Schema) Unindex 

func (s *Schema) Unindex(o Object)
type Search struct {
	// contains filtered or unexported fields
}

Search helper structure to easily build search queries on objects and retrieve the results

func (*Search) And 

func (s *Search) And(field, operator string, value interface{}) *Search

And performs a new Search while "ANDing" search results

func (*Search) Collect 

func (s *Search) Collect() (out []Object, err error)

Collect all the objects resulting from the search. If a search has been made on an indexed field, results will be in descending order by default. If you want to change result order, call Reverse before. NB: only search on indexed field(s) will be garanteed to be ordered according to the last field searched.

func (*Search) Err 

func (s *Search) Err() error

Err return any error encountered while searching

func (*Search) Iterator 

func (s *Search) Iterator() (it *Iterator, err error)

Iterator returns an Iterator convenient to iterate over the objects resulting from the search

func (*Search) Len 

func (s *Search) Len() int

Len returns the number of data returned by the search

func (*Search) Limit added in v1.2.0 

func (s *Search) Limit(limit uint64) *Search

Limit the number of results collected by Collect function

func (*Search) One added in v1.3.0 

func (s *Search) One() (o Object, err error)

One returns the first result found calling Collect function. If no Object is found, ErrNoObjectFound is returned

func (*Search) Or 

func (s *Search) Or(field, operator string, value interface{}) *Search

And performs a new Search while "ORing" search results

func (*Search) Reverse added in v1.1.0 

func (s *Search) Reverse() *Search

Reverse the order the results are collected by Collect function

Source Files

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