schema

type Action struct {
	Name  string
	Child Exp
}

type Child Exp

type ChildKind string

type Entity struct {
	Name      string
	Relations []Relation
	Actions   []Action

	// option
	EntityOption EntityOption
}

type EntityOption struct {
	Table      string
	Identifier string
}

type Exp interface {
	GetType() string
	GetKind() string
}

type Leaf struct {
	Type  LeafType // tupleToUserSet or computedUserSet
	Value string
}

type LeafType string

type OPType string

type Relation struct {
	Name string
	Type string

	// option
	RelationOption RelationOption
}

type RelationOption struct {
	Table string
	Rel   RelationType
	Cols  []string
}

type RelationType string

type Relations []Relation

type Rewrite struct {
	Type     OPType // union or intersection
	Children []Child
}

type Schema struct {
	// all entities
	Entities map[string]Entity

	// all tables
	Tables map[string]TableType

	// table name to entities
	TableToEntity map[string]Entity

	// pivot name to entities
	PivotToEntity map[string]Entity

	// pivot name to relation
	PivotToRelation map[string]Relation
}

type TableType string