New texts to reverse a "to_many" into "to_one"

templates.go

@@ -158,8 +158,9 @@ var templateFunctions = template.FuncMap{
 	"whereClause": strmangle.WhereClause,
 
 	// Text helpers
-	"textsFromForeignKey":   textsFromForeignKey,
+	"textsFromForeignKey":           textsFromForeignKey,
-	"textsFromRelationship": textsFromRelationship,
+	"textsFromOneToOneRelationship": textsFromOneToOneRelationship,
+	"textsFromRelationship":         textsFromRelationship,
 
 	// dbdrivers ops
 	"driverUsesLastInsertID":       strmangle.DriverUsesLastInsertID,

text_helpers.go

@@ -28,8 +28,9 @@ type RelationshipToOneTexts struct {
 		PackageName string
 		Name        string
 
-		Varname  string
+		Varname     string
-		Receiver string
+		Receiver    string
+		ReverseArgs bool
 
 		LocalAssignment   string
 		ForeignAssignment string
@@ -72,6 +73,25 @@ func textsFromForeignKey(packageName string, tables []bdb.Table, table bdb.Table
 	return r
 }
 
+func textsFromOneToOneRelationship(packageName string, tables []bdb.Table, table bdb.Table, toMany bdb.ToManyRelationship) RelationshipToOneTexts {
+	fkey := bdb.ForeignKey{
+		Name:     "none",
+		Column:   toMany.Column,
+		Nullable: toMany.Nullable,
+		Unique:   toMany.Unique,
+
+		ForeignTable:          toMany.ForeignTable,
+		ForeignColumn:         toMany.ForeignColumn,
+		ForeignColumnNullable: toMany.ForeignColumnNullable,
+		ForeignColumnUnique:   toMany.ForeignColumnUnique,
+	}
+
+	rel := textsFromForeignKey(packageName, tables, table, fkey)
+	rel.Function.Name = strmangle.TitleCase(strmangle.Singular(toMany.ForeignTable))
+	rel.Function.ReverseArgs = true
+	return rel
+}
+
 // RelationshipToManyTexts contains text that will be used by templates.
 type RelationshipToManyTexts struct {
 	LocalTable struct {

text_helpers_test.go

@@ -20,7 +20,7 @@ func (fakeDB) Columns(tableName string) ([]bdb.Column, error) {
 		"contests": []bdb.Column{{Name: "id", Type: "int32", Nullable: true}},
 		"videos": []bdb.Column{
 			{Name: "id", Type: "int32"},
-			{Name: "user_id", Type: "int32", Nullable: true},
+			{Name: "user_id", Type: "int32", Nullable: true, Unique: true},
 			{Name: "contest_id", Type: "int32"},
 		},
 		"notifications": []bdb.Column{
@@ -92,6 +92,7 @@ func TestTextsFromForeignKey(t *testing.T) {
 	expect.Function.Name = "User"
 	expect.Function.Varname = "user"
 	expect.Function.Receiver = "v"
+	expect.Function.ReverseArgs = false
 
 	expect.Function.LocalAssignment = "UserID.Int32"
 	expect.Function.ForeignAssignment = "ID"
@@ -101,6 +102,52 @@ func TestTextsFromForeignKey(t *testing.T) {
 	}
 }
 
+func TestTextsFromOneToOneRelationship(t *testing.T) {
+	t.Parallel()
+
+	tables, err := bdb.Tables(fakeDB(0))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	users := bdb.GetTable(tables, "users")
+	texts := textsFromOneToOneRelationship("models", tables, users, users.ToManyRelationships[0])
+	expect := RelationshipToOneTexts{}
+
+	expect.ForeignKey = bdb.ForeignKey{
+		Name:     "none",
+		Column:   "id",
+		Nullable: false,
+		Unique:   false,
+
+		ForeignTable:          "videos",
+		ForeignColumn:         "user_id",
+		ForeignColumnNullable: true,
+		ForeignColumnUnique:   true,
+	}
+
+	expect.LocalTable.NameGo = "User"
+	expect.LocalTable.ColumnNameGo = "ID"
+
+	expect.ForeignTable.Name = "videos"
+	expect.ForeignTable.NameGo = "Video"
+	expect.ForeignTable.ColumnName = "user_id"
+	expect.ForeignTable.ColumnNameGo = "UserID"
+
+	expect.Function.PackageName = "models"
+	expect.Function.Name = "Video"
+	expect.Function.Varname = "video"
+	expect.Function.Receiver = "u"
+	expect.Function.ReverseArgs = true
+
+	expect.Function.LocalAssignment = "ID"
+	expect.Function.ForeignAssignment = "UserID.Int32"
+
+	if !reflect.DeepEqual(expect, texts) {
+		t.Errorf("Want:\n%s\nGot:\n%s\n", spew.Sdump(expect), spew.Sdump(texts))
+	}
+}
+
 func TestTextsFromRelationship(t *testing.T) {
 	t.Parallel()