schema: add PrimaryKeyColumns method to Table, useful for 'without rowid' tables

pkg/schema/table.go

@@ -1,6 +1,7 @@
 package schema
 
 import (
+	"sort"
 	"strings"
 
 	"git.offline-twitter.com/offline-labs/gas-stack/pkg/textutils"
@@ -83,6 +84,23 @@ type Table struct {
 	GoTypeName string
 }
 
+// PrimaryKeyColumns returns the ordered list of columns in this table's primary key.
+// This can be useful for "without rowid" tables with composite primary keys.
+//
+// TODO: needs test
+func (t Table) PrimaryKeyColumns() []Column {
+	pks := make([]Column, 0)
+	for _, c := range t.Columns {
+		if c.IsPrimaryKey {
+			pks = append(pks, c)
+		}
+	}
+	sort.Slice(pks, func(i, j int) bool {
+		return pks[i].PrimaryKeyRank < pks[j].PrimaryKeyRank
+	})
+	return pks
+}
+
 func (t Table) HasAutoTimestamps() (hasCreatedAt bool, hasUpdatedAt bool) {
 	for _, c := range t.Columns {
 		if c.Name == "created_at" && c.Type == "integer" {