From 2a38ae39982e34de4400c8790c45885806505095 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vin=C3=ADcius=20Garcia?= <vingarcia00@gmail.com>
Date: Sun, 13 Jun 2021 15:11:17 -0300
Subject: [PATCH] Improve Update method to return ErrRecordNotFound if no rows
 were updated

---
 ksql.go      | 18 ++++++++++++++++--
 ksql_test.go | 14 ++++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/ksql.go b/ksql.go
index 1f9195f..b359b36 100644
--- a/ksql.go
+++ b/ksql.go
@@ -541,9 +541,23 @@ func (c DB) Update(
 		return err
 	}
 
-	_, err = c.db.ExecContext(ctx, query, params...)
+	result, err := c.db.ExecContext(ctx, query, params...)
+	if err != nil {
+		return err
+	}
 
-	return err
+	n, err := result.RowsAffected()
+	if err != nil {
+		return fmt.Errorf(
+			"unexpected error: unable to fetch how many rows were affected by the update: %s",
+			err,
+		)
+	}
+	if n < 1 {
+		return ErrRecordNotFound
+	}
+
+	return nil
 }
 
 func buildInsertQuery(
diff --git a/ksql_test.go b/ksql_test.go
index 3eea91a..eccec01 100644
--- a/ksql_test.go
+++ b/ksql_test.go
@@ -1026,6 +1026,20 @@ func TestUpdate(t *testing.T) {
 				assert.Equal(t, 42, result.Age)
 			})
 
+			t.Run("should return ErrRecordNotFound when asked to update an inexistent user", func(t *testing.T) {
+				db := connectDB(t, driver)
+				defer db.Close()
+
+				ctx := context.Background()
+				c := newTestDB(db, driver)
+
+				err = c.Update(ctx, UsersTable, User{
+					ID:   4200,
+					Name: "Thayane",
+				})
+				assert.Equal(t, ErrRecordNotFound, err)
+			})
+
 			t.Run("should report database errors correctly", func(t *testing.T) {
 				db := connectDB(t, driver)
 				defer db.Close()