CODEWITHSUNDEEP
c#.netentity-frameworkrestasp.net-web-api
Mehrdad Kamali
Mehrdad Kamali

Reputation: 87

Prevent collision on multiple database calls in Web API

I have a table of random unique number that they served as account Id for a user.

This scenario will use in Register method of Web API to get first unique Number and attached it into a user and after a successful creation, the fetched unique Number will be removed from database:

        public async Task<ActionResult> Register([FromBody] RegisterDto model)
    {

        //get the first unique number from the database
        var UniqueNumber = _context.UniqueNumbers.First();


        var user = new User
        {
            UserName = model.Email,
            Email = model.Email,
            PhoneNumber = model.PhoneNumber,
            FirstName = model.FirstName,
            LastName = model.LastName,
            UserProfile = new UserProfile()
            {
                AccountNumber = UniqueNumber.Number,
            },
        };

        //creating user
        var createResult = await _userManager.CreateAsync(user, model.Password);
        if (!createResult.Succeeded) return BadRequest(new { isSucceeded = createResult.Succeeded, errors = createResult.Errors });

        //Delete the fetched UniqueId from the database
        _context.UniqueNumbers.Remove(UniqueNumber);
        _context.SaveChanges();

        return Ok(new
        {
            isSucceeded = true
        });
    }

My question is how do I prevent collision in multiple calls on API since it may return same unique number for multiple calls?

Upvotes: 0

Views: 220

Answers (1)

David Browne - Microsoft
David Browne - Microsoft

Reputation: 88852

On EF Core and Microsoft SQL Server you should simply use a SEQUENCE object to generate your keys. See Sequences - EF Core

If really, really want to proceed with your original design you could use FromSql to run a DELETE … OUTPUT, something like:

var UniqueNumber = _context.UniqueNumbers.FromSql("delete top (1) from UniqueNumbers output deleted.*").Single();

Upvotes: 1

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