In SQL, is UPDATE always faster than DELETE+INSERT?

Question

Say I have a simple table that has the following fields:

1. ID: int, autoincremental (identity), primary key
2. Name: varchar(50), unique, has unique index
3. Tag: int

I never use the ID field for lookup, because my application is always based on working with the Name field.

I need to change the Tag value from time to time. I'm using the following trivial SQL code:

UPDATE Table SET Tag = XX WHERE Name = YY; 

I wondered if anyone knows whether the above is always faster than:

DELETE FROM Table WHERE Name = YY; INSERT INTO Table (Name, Tag) VALUES (YY, XX); 

Again - I know that in the second example the ID is changed, but it does not matter for my application.

Answer 1

A bit too late with this answer, but since I faced a similar question, I made a test with JMeter and a MySQL server on same machine, where I have used:

1. A transaction Controller (generating parent sample) that contained two JDBC Requests: a Delete and an Insert statement
2. A sepparate JDBC Request containing the Update statement.

After running the test for 500 loops, I have obtained the following results:

DEL + INSERT - Average: 62ms

Update - Average: 30ms

Results: