pgstmt: add on conflict on constraint (#15)

pgstmt/insert.go

@@ -18,6 +18,7 @@ type InsertStatement interface {
 	Values(values ...interface{})
 	Select(f func(b SelectStatement))
 	OnConflict(target ...string) OnConflict
+	OnConflictOnConstraint(constraintName string) OnConflict
 	Returning(col ...string)
 }
 
@@ -82,6 +83,11 @@ func (st *insertStmt) OnConflict(target ...string) OnConflict {
 	return st.conflict
 }
 
+func (st *insertStmt) OnConflictOnConstraint(constraintName string) OnConflict {
+	st.conflict = &conflict{constraint: constraintName}
+	return st.conflict
+}
+
 func (st *insertStmt) Returning(col ...string) {
 	st.returning.pushString(col...)
 }
@@ -109,8 +115,15 @@ func (st *insertStmt) make() *buffer {
 	}
 	if st.conflict != nil {
 		b.push("on conflict")
+
+		// on conflict can be one of
+		// => ( { index_column_name | ( index_expression ) } [ COLLATE collation ] [ opclass ] [, ...] ) [ WHERE index_predicate ]
+		// => ON CONSTRAINT constraint_name
 		if len(st.conflict.targets) > 0 {
 			b.push(parenString(st.conflict.targets...))
+		} else if st.conflict.constraint != "" {
+			b.push("on constraint")
+			b.push(st.conflict.constraint)
 		}
 		if st.conflict.doNothing {
 			b.push("do nothing")
@@ -127,9 +140,10 @@ func (st *insertStmt) make() *buffer {
 }
 
 type conflict struct {
-	targets   []string
-	doNothing bool
-	doUpdate  *updateStmt
+	targets    []string
+	constraint string
+	doNothing  bool
+	doUpdate   *updateStmt
 }
 
 func (st *conflict) DoNothing() {

pgstmt/insert_test.go

@@ -83,4 +83,35 @@ func TestInsert(t *testing.T) {
 			args,
 		)
 	})
+
+	t.Run("insert on conflict on constraint do update", func(t *testing.T) {
+		q, args := pgstmt.Insert(func(b pgstmt.InsertStatement) {
+			b.Into("users")
+			b.Columns("username", "email")
+			b.Value("tester1", "tester1@localhost")
+			b.OnConflictOnConstraint("username_key").DoUpdate(func(b pgstmt.UpdateStatement) {
+				b.Set("email").ToRaw("excluded.email")
+				b.Set("updated_at").ToRaw("now()")
+			})
+			b.Returning("id")
+		}).SQL()
+
+		assert.Equal(t,
+			stripSpace(`
+				insert into users (username, email)
+				values ($1, $2)
+				on conflict on constraint username_key do update
+				set email = excluded.email,
+					updated_at = now()
+				returning id
+			`),
+			q,
+		)
+		assert.EqualValues(t,
+			[]interface{}{
+				"tester1", "tester1@localhost",
+			},
+			args,
+		)
+	})
 }