er

Documentation

Overview

Package er is mermaid entity relationship diagram builder.

Index

• type Attribute
• type Diagram
  • func NewDiagram(w io.Writer, opts ...Option) *Diagram
  • func (d *Diagram) Build() error
  • func (d *Diagram) NoRelationship(e Entity) *Diagram
  • func (d *Diagram) Relationship(leftE, rightE Entity, leftR, rightR Relationship, identidy Identify, ...) *Diagram
  • func (d *Diagram) String() string
• type Entity
  • func NewEntity(name string, attrs []*Attribute) Entity
• type Identify
• type Option
• type Relationship

Types

type Attribute

type Attribute struct {
	// Type is the type of the attribute.
	Type string
	// Name is the name of the attribute.
	Name string
	// IsPrimaryKey is the flag that indicates whether the attribute is a primary key.
	IsPrimaryKey bool
	// IsForeignKey is the flag that indicates whether the attribute is a foreign key.
	IsForeignKey bool
	// IsUniqueKey is the flag that indicates whether the attribute is a unique key.
	IsUniqueKey bool
	// Comment is the comment of the attribute.
	Comment string
}

Attribute is a attribute of the entity.

type Diagram

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

Diagram is a entity relationship diagram builder.

func NewDiagram

func NewDiagram(w io.Writer, opts ...Option) *Diagram

NewDiagram returns a new Diagram.

func (*Diagram) Build

func (d *Diagram) Build() error

Build writes the entity relationship body to the output destination.

func (*Diagram) NoRelationship

func (d *Diagram) NoRelationship(e Entity) *Diagram

NoRelationship adds an entity that has no relationships.

func (*Diagram) Relationship

func (d *Diagram) Relationship(leftE, rightE Entity, leftR, rightR Relationship, identidy Identify, comment string) *Diagram

Relationship is a relationship of entity relationship. leftE: left entity rightE: right entity leftR: left relationship. You choice from Relationship constants (e.g. ZeroToOneRelationship) rightR: right relationship. You choice from Relationship constants (e.g. ZeroToOneRelationship) identidy: identify of the relationship. You choice from Identify constants (e.g. Identifying)

func (*Diagram) String

func (d *Diagram) String() string

String returns the entity relationship diagram body.

type Entity

type Entity struct {
	// Name is the name of the entity.
	Name string
	// Attributes is the attributes of the entity.
	Attributes []*Attribute
}

Entity is a entity of entity relationship.

func NewEntity

func NewEntity(name string, attrs []*Attribute) Entity

NewEntity returns a new Entity.

type Identify

type Identify bool

Identify is a type that represents the relationship between entities in an entity relationship diagram. Relationships may be classified as either identifying or non-identifying and these are rendered with either solid or dashed lines respectively.

const (
	// Identifying is a constant that represents an identifying relationship.
	// It represents "--" in the entity relationship diagram.
	Identifying Identify = true
	// NonIdentifying is a constant that represents a non-identifying relationship.
	// It represents ".." in the entity relationship diagram.
	NonIdentifying Identify = false
)

type Option

type Option func(*config)

Option sets the options for the PieChart struct.

type Relationship

type Relationship string

Relationship is a type that represents the relationship between entities.

const (
	// ZeroToOneRelationship is a constant that represents a zero to one relationship.
	// e.g. "|o" or "o|"
	ZeroToOneRelationship Relationship = "zero_to_one"
	// ExactlyOneRelationship is a constant that represents an exactly one relationship.
	// e.g. "||"
	ExactlyOneRelationship Relationship = "exactly_one"
	// ZeroToMoreRelationship is a constant that represents a zero to more relationship.
	// e.g. "}o" or "o{}"
	ZeroToMoreRelationship Relationship = "zero_to_more"
	// OneToMoreRelationship is a constant that represents a one to more relationship.
	// e.g. "}|" or "|}"
	OneToMoreRelationship Relationship = "one_to_more"
)