ddl

type AddColumn struct {
	Dialect dialect
	Table   string
	Column  *Column
}

type Column struct {
	Ident string
	Type  *ColumnType

	Default string

	// implementation variations
	Meta map[string]interface{}

	Comment string
}

type ColumnType struct {
	Name string

	Null bool

	// implementation variations
	Meta map[string]interface{}
}

type CreateIndex struct {
	Dialect               dialect
	Index                 *Index
	OmitIfNotExistsClause bool
	OmitFieldLength       bool
}

type CreateTable struct {
	Dialect               dialect
	Table                 *Table
	OmitIfNotExistsClause bool
	SuffixClause          string
}

type DataDefiner interface {
	ConvertModel(*dal.Model) (*Table, error)
	ConvertAttribute(attr *dal.Attribute) (*Column, error)

	// Tables(ctx context.Context) ([]*Table, error)
	TableLookup(context.Context, string) (*Table, error)
	TableCreate(context.Context, *Table) error
	TableDrop(context.Context, string) error

	ColumnAdd(context.Context, string, *Column) error
	ColumnDrop(context.Context, string, string) error
	ColumnRename(context.Context, string, string, string) error
	ColumnReType(context.Context, string, string, *ColumnType) error

	IndexLookup(context.Context, string, string) (*Index, error)
	IndexCreate(context.Context, string, *Index) error
	IndexDrop(context.Context, string, string) error
}

type DropColumn struct {
	Dialect dialect
	Table   string
	Column  string
}

type DropIndex struct {
	Dialect    dialect
	Ident      string
	TableIdent string
}

type DropTable struct {
	Dialect dialect
	Table   string
}

type Index struct {
	TableIdent string
	Ident      string
	Type       string
	Fields     []*IndexField
	Unique     bool
	Predicate  string
	Comment    string

	// implementation variations
	Meta map[string]interface{}
}

type IndexField struct {
	// Expression or a single column
	Column string

	Length int

	// Wrap part in parentheses
	Expression string

	// Ascending or descending
	Sort  dal.IndexFieldSort
	Nulls dal.IndexFieldNulls

	Statistics *IndexFieldStatistics

	// implementation variations
	Meta map[string]interface{}
}

type IndexFieldStatistics struct {
	// Cardinality is an indicator that refers to the uniqueness
	// of all values in a column. Low cardinality means a lot
	// of duplicate values in that column. For example, a column
	// that stores the gender values has low cardinality.
	// In contrast, high cardinality means that there are many distinct values.
	Cardinality int64
}

type ReTypeColumn struct {
	Dialect dialect
	Table   string
	Column  string
	Type    *ColumnType
}

type RenameColumn struct {
	Dialect dialect
	Table   string
	Old     string
	New     string
}

type Table struct {
	Ident   string
	Columns []*Column
	Indexes []*Index
	Comment string

	Temporary bool

	// implementation variations
	Meta map[string]interface{}
}