dialect/sql: remove all DDL builders that no longer used (#4369)

dialect/sql/schema/schema.go

@@ -430,28 +430,6 @@ type ForeignKey struct {
 	OnDelete   ReferenceOption // action on delete.
 }
 
-// DSL returns a default DSL query for a foreign-key.
-func (fk ForeignKey) DSL() *sql.ForeignKeyBuilder {
-	cols := make([]string, len(fk.Columns))
-	refs := make([]string, len(fk.RefColumns))
-	for i, c := range fk.Columns {
-		cols[i] = c.Name
-	}
-	for i, c := range fk.RefColumns {
-		refs[i] = c.Name
-	}
-	dsl := sql.ForeignKey().Symbol(fk.Symbol).
-		Columns(cols...).
-		Reference(sql.Reference().Table(fk.RefTable.Name).Columns(refs...))
-	if action := string(fk.OnDelete); action != "" {
-		dsl.OnDelete(action)
-	}
-	if action := string(fk.OnUpdate); action != "" {
-		dsl.OnUpdate(action)
-	}
-	return dsl
-}
-
 // ReferenceOption for constraint actions.
 type ReferenceOption string
 
@@ -479,24 +457,6 @@ type Index struct {
 	realname   string                  // real name in the database (Postgres only).
 }
 
-// Builder returns the query builder for index creation. The DSL is identical in all dialects.
-func (i *Index) Builder(table string) *sql.IndexBuilder {
-	idx := sql.CreateIndex(i.Name).Table(table)
-	if i.Unique {
-		idx.Unique()
-	}
-	for _, c := range i.Columns {
-		idx.Column(c.Name)
-	}
-	return idx
-}
-
-// DropBuilder returns the query builder for the drop index.
-func (i *Index) DropBuilder(table string) *sql.DropIndexBuilder {
-	idx := sql.DropIndex(i.Name).Table(table)
-	return idx
-}
-
 // Indexes used for scanning all sql.Rows into a list of indexes, because
 // multiple sql rows can represent the same index (multi-columns indexes).
 type Indexes []*Index