Simple Database Manipulation

Querying

Inserting

Use DbSet.AddAsync to track the given object. Use DbSet.SaveChangesAsync to apply tracked insertions.

[HttpPost]
[ProducesResponseType(typeof(Movie), StatusCodes.Status201Created)]
public async Task<IActionResult> Create([FromBody] Movie movie)
{
    await context.Movies.AddAsync(movie);
    await context.SaveChangesAsync();
    // ..
}

Auto-assign id

When posting request to insert new records, id is not required, it should be auto-generated. EFCore can handle this behind the scene. Once DbContext.SaveChangesAsync is invoked, EFCore auto calculates the id from database for the added object.

[HttpPost]
[ProducesResponseType(typeof(Movie), StatusCodes.Status201Created)]
public async Task<IActionResult> Create([FromBody] Movie movie)
{
    await context.Movies.AddAsync(movie);
    await context.SaveChangesAsync();
    return CreatedAtAction(nameof(Get), new { id = movie.Id }, movie);
}

Updating

EFCore keep tracking the queried object, any modification will be handled when SaveChangesAsync invoked.

[HttpPut("{id:int}")]
[ProducesResponseType(typeof(Movie), StatusCodes.Status200OK)]
[ProducesResponseType(StatusCodes.Status404NotFound)]
public async Task<IActionResult> Update([FromRoute] int id, [FromBody] Movie movie)
{
    Movie? existing = await context.Movies.FindAsync(id);
    if (existing is null)
        return NotFound();
    
    (existing.Title, existing.Synopsis, existing.ReleaseDate) =
        (movie.Title, movie.Synopsis, movie.ReleaseDate);
    await context.SaveChangesAsync();
    return Ok(existing);
}

Deleting

[HttpDelete("{id:int}")]
[ProducesResponseType(StatusCodes.Status200OK)]
[ProducesResponseType(StatusCodes.Status404NotFound)]
public async Task<IActionResult> Remove([FromRoute] int id)
{
    Movie? existing = await context.Movies.FindAsync(id);
    if (existing is null)
        return NotFound();
    context.Movies.Remove(existing);
    // can also delete from dbcontext since there's only one DbSet<Movie> in it.
    // context.Remove(existing);
    await context.SaveChangesAsync();
    return Ok();

Also, EFCore knows how to find the row to delete by unique property.

[HttpDelete("{id:int}")]
[ProducesResponseType(StatusCodes.Status200OK)]
[ProducesResponseType(StatusCodes.Status404NotFound)]
public async Task<IActionResult> Remove([FromRoute] int id)
{
    // still need to guard here but I just omit it...
    context.Movies.Remove(new Movie { Id = id }); // Just delete by id!
    await context.SaveChangesAsync();
    return Ok();
}