database

package
v0.10.1 Latest Latest
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 Go to latest Published: Jan 28, 2021 License: MIT Imports: 11 Imported by: 0

Documentation

Overview

Package database provides database primitives such as tables, transactions and indexes.

Index

Constants

This section is empty.

Variables

View Source 
var (
	// ErrTableNotFound is returned when the targeted table doesn't exist.
	ErrTableNotFound = errors.New("table not found")

	// ErrTableAlreadyExists is returned when attempting to create a table with the
	// same name as an existing one.
	ErrTableAlreadyExists = errors.New("table already exists")

	// ErrIndexNotFound is returned when the targeted index doesn't exist.
	ErrIndexNotFound = errors.New("index not found")

	// ErrIndexAlreadyExists is returned when attempting to create an index with the
	// same name as an existing one.
	ErrIndexAlreadyExists = errors.New("index already exists")

	// ErrDocumentNotFound is returned when no document is associated with the provided key.
	ErrDocumentNotFound = errors.New("document not found")

	// ErrDuplicateDocument is returned when another document is already associated with a given key, primary key,
	// or if there is a unique index violation.
	ErrDuplicateDocument = errors.New("duplicate document")
)

Functions

This section is empty.

Types

type Database 

type Database struct {

	// Codec used to encode documents. Defaults to MessagePack.
	Codec encoding.Codec
	// contains filtered or unexported fields
}

A Database manages a list of tables in an engine.

func New 

func New(ctx context.Context, ng engine.Engine, opts Options) (*Database, error)

New initializes the DB using the given engine.

func (*Database) Begin 

func (db *Database) Begin(writable bool) (*Transaction, error)

Begin starts a new transaction with default options. The returned transaction must be closed either by calling Rollback or Commit.

func (*Database) BeginTx added in v0.8.0 

func (db *Database) BeginTx(ctx context.Context, opts *TxOptions) (*Transaction, error)

BeginTx starts a new transaction with the given options. If opts is empty, it will use the default options. The returned transaction must be closed either by calling Rollback or Commit. If the Attached option is passed, it opens a database level transaction, which gets attached to the database and prevents any other transaction to be opened afterwards until it gets rolled back or commited.

func (*Database) Close 

func (db *Database) Close() error

Close the underlying engine.

func (*Database) GetAttachedTx added in v0.8.0 

func (db *Database) GetAttachedTx() *Transaction

GetAttachedTx returns the transaction attached to the database. It returns nil if there is no such transaction. The returned transaction is not thread safe.

type FieldConstraint 

type FieldConstraint struct {
	Path         document.Path
	Type         document.ValueType
	IsPrimaryKey bool
	IsNotNull    bool
	DefaultValue document.Value
}

FieldConstraint describes constraints on a particular field.

func (*FieldConstraint) HasDefaultValue added in v0.9.0 

func (f *FieldConstraint) HasDefaultValue() bool

func (*FieldConstraint) ScanDocument 

func (f *FieldConstraint) ScanDocument(d document.Document) error

ScanDocument implements the document.Scanner interface.

func (*FieldConstraint) ToDocument 

func (f *FieldConstraint) ToDocument() document.Document

ToDocument returns a document from f.

type FieldConstraints added in v0.9.0 

type FieldConstraints []FieldConstraint

FieldConstraints is a list of field constraints.

func (FieldConstraints) Convert added in v0.9.0 

func (f FieldConstraints) Convert(d document.Document) (*document.FieldBuffer, error)

Convert the document using the field constraints. It converts any path that has a field constraint on it into the specified type. If there is no constraint on an integer field or value, it converts it into a double. Default values on missing fields are not applied.

func (FieldConstraints) ValidateDocument added in v0.9.0 

func (f FieldConstraints) ValidateDocument(d document.Document) (*document.FieldBuffer, error)

ValidateDocument calls Convert then ensures the document validates against the field constraints.

type Index 

type Index struct {
	*index.Index
	Opts IndexConfig
}

Index of a table field. Contains information about the index configuration and provides methods to manipulate the index.

type IndexConfig 

type IndexConfig struct {
	TableName string
	IndexName string
	Path      document.Path

	// If set to true, values will be associated with at most one key. False by default.
	Unique bool

	// If set, the index is typed and only accepts that type
	Type document.ValueType
}

IndexConfig holds the configuration of an index.

func (*IndexConfig) ScanDocument 

func (i *IndexConfig) ScanDocument(d document.Document) error

ScanDocument implements the document.Scanner interface.

func (*IndexConfig) ToDocument 

func (i *IndexConfig) ToDocument() document.Document

ToDocument creates a document from an IndexConfig.

type Options added in v0.8.0 

type Options struct {
	Codec encoding.Codec
}

type Table 

type Table struct {
	Store engine.Store
	// contains filtered or unexported fields
}

A Table represents a collection of documents.

func (*Table) AscendGreaterOrEqual added in v0.10.0 

func (t *Table) AscendGreaterOrEqual(pivot document.Value, fn func(d document.Document) error) error

AscendGreaterOrEqual iterates over the documents of the table whose key is greater than or equal to the pivot. The pivot is converted to the type of the primary key, if any, prior to iteration. If the pivot is empty, it iterates from the beginning of the table.

func (*Table) Delete 

func (t *Table) Delete(key []byte) error

Delete a document by key. Indexes are automatically updated.

func (*Table) DescendLessOrEqual added in v0.10.0 

func (t *Table) DescendLessOrEqual(pivot document.Value, fn func(d document.Document) error) error

DescendLessOrEqual iterates over the documents of the table whose key is less than or equal to the pivot, in reverse order. The pivot is converted to the type of the primary key, if any, prior to iteration. If the pivot is empty, it iterates from the end of the table in reverse order.

func (*Table) EncodeValueToKey added in v0.10.0 

func (t *Table) EncodeValueToKey(v document.Value) ([]byte, error)

EncodeValueToKey encodes a value following primary key constraints. It returns a binary representation of the key as used in the store. It can be used to manually add a new entry to the store or to compare with other keys during table iteration.

func (*Table) GetDocument 

func (t *Table) GetDocument(key []byte) (document.Document, error)

GetDocument returns one document by key.

func (*Table) Indexes 

func (t *Table) Indexes() (map[string]Index, error)

Indexes returns a map of all the indexes of a table.

func (*Table) Info added in v0.7.0 

func (t *Table) Info() (*TableInfo, error)

Info of the table.

func (*Table) Insert 

func (t *Table) Insert(d document.Document) (document.Document, error)

Insert the document into the table. If a primary key has been specified during the table creation, the field is expected to be present in the given document. If no primary key has been selected, a monotonic autoincremented integer key will be generated. It returns the inserted document alongside its key. They key can be accessed using the document.Keyer interface.

func (*Table) Iterate 

func (t *Table) Iterate(fn func(d document.Document) error) error

Iterate goes through all the documents of the table and calls the given function by passing each one of them. If the given function returns an error, the iteration stops.

func (*Table) Name added in v0.7.0 

func (t *Table) Name() string

Name returns the name of the table.

func (*Table) ReIndex added in v0.7.0 

func (t *Table) ReIndex() error

ReIndex all the indexes of the table.

func (*Table) Replace 

func (t *Table) Replace(key []byte, d document.Document) error

Replace a document by key. An error is returned if the key doesn't exist. Indexes are automatically updated.

func (*Table) Truncate 

func (t *Table) Truncate() error

Truncate deletes all the documents from the table.

func (*Table) Tx added in v0.8.0 

func (t *Table) Tx() *Transaction

Tx returns the current transaction.

type TableInfo added in v0.7.0 

type TableInfo struct {
	FieldConstraints FieldConstraints
	// contains filtered or unexported fields
}

TableInfo contains information about a table.

func (*TableInfo) GetPrimaryKey added in v0.7.0 

func (ti *TableInfo) GetPrimaryKey() *FieldConstraint

GetPrimaryKey returns the field constraint of the primary key. Returns nil if there is no primary key.

func (*TableInfo) ScanDocument added in v0.7.0 

func (ti *TableInfo) ScanDocument(d document.Document) error

ScanDocument decodes d into ti.

func (*TableInfo) ToDocument added in v0.7.0 

func (ti *TableInfo) ToDocument() document.Document

ToDocument turns ti into a document.

type Transaction 

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

Transaction represents a database transaction. It provides methods for managing the collection of tables and the transaction itself. Transaction is either read-only or read/write. Read-only can be used to read tables and read/write can be used to read, create, delete and modify tables.

func (*Transaction) AddField added in v0.9.0 

func (tx *Transaction) AddField(tableName string, fc FieldConstraint) error

AddField adds a field constraint to a table.

func (*Transaction) Commit 

func (tx *Transaction) Commit() error

Commit the transaction. Calling this method on read-only transactions will return an error.

func (*Transaction) CreateIndex 

func (tx *Transaction) CreateIndex(opts IndexConfig) error

CreateIndex creates an index with the given name. If it already exists, returns ErrIndexAlreadyExists.

func (*Transaction) CreateTable 

func (tx *Transaction) CreateTable(name string, info *TableInfo) error

CreateTable creates a table with the given name. If it already exists, returns ErrTableAlreadyExists.

func (*Transaction) DB added in v0.8.0 

func (tx *Transaction) DB() *Database

DB returns the underlying database that created the transaction.

func (*Transaction) DropIndex 

func (tx *Transaction) DropIndex(name string) error

DropIndex deletes an index from the database.

func (*Transaction) DropTable 

func (tx *Transaction) DropTable(name string) error

DropTable deletes a table from the database.

func (*Transaction) GetIndex 

func (tx *Transaction) GetIndex(name string) (*Index, error)

GetIndex returns an index by name.

func (*Transaction) GetTable 

func (tx *Transaction) GetTable(name string) (*Table, error)

GetTable returns a table by name. The table instance is only valid for the lifetime of the transaction.

func (*Transaction) ListIndexes 

func (tx *Transaction) ListIndexes() ([]*IndexConfig, error)

ListIndexes lists all indexes.

func (*Transaction) ReIndex 

func (tx *Transaction) ReIndex(indexName string) error

ReIndex truncates and recreates selected index from scratch.

func (*Transaction) ReIndexAll 

func (tx *Transaction) ReIndexAll() error

ReIndexAll truncates and recreates all indexes of the database from scratch.

func (*Transaction) RenameTable added in v0.7.0 

func (tx *Transaction) RenameTable(oldName, newName string) error

RenameTable renames a table. If it doesn't exist, it returns ErrTableNotFound.

func (*Transaction) Rollback 

func (tx *Transaction) Rollback() error

Rollback the transaction. Can be used safely after commit.

func (*Transaction) Writable 

func (tx *Transaction) Writable() bool

Writable indicates if the transaction is writable or not.

type TxOptions added in v0.8.0 

type TxOptions struct {
	// Open a read-only transaction.
	ReadOnly bool
	// Set the transaction as global at the database level.
	// Any queries run by the database will use that transaction until it is
	// rolled back or commited.
	Attached bool
}

TxOptions are passed to Begin to configure transactions.

Source Files

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