EF coreTracking vs Non Tracking query - entity-framework

Question

I'm new to EF core 6. I came across tracking vs non tracking query. I'm puzzled where to use it. My objective is to write a webapi with ef core where I see no need for tracking query. Can some one please clarify the difference between both. For webapi is there any need to track the query. Please help me on this.

Answer 1

If you're going to update the entity, use a tracking query so that the changes are persisted when you call SaveChanges on the DbContext. If the action is read only (i.e. HTTP GET) then use a non-tracking query.
e.g. for a WebApi controller:
[Route("api/[controller]")]
[ApiController]
public class ValuesController : ControllerBase
{
// GET api/values
[HttpGet]
public ActionResult<IEnumerable<string>> Get()
{
// non-tracking
return new string[] { "value1", "value2" };
}
// GET api/values/5
[HttpGet("{id}")]
public ActionResult<string> Get(int id)
{
// non-tracking
return "value";
}
// POST api/values
[HttpPost]
public void Post([FromBody] string value)
{
// tracking
}
// PUT api/values/5
[HttpPut("{id}")]
public void Put(int id, [FromBody] string value)
{
// tracking
}
// DELETE api/values/5
[HttpDelete("{id}")]
public void Delete(int id)
{
// tracking
}
}