CODEWITHSUNDEEP
asp.net-mvcasp.net-mvc-4primary-key
Neeraj Mehta
Neeraj Mehta

Reputation: 1705

Violation of PRIMARY KEY constraint Cannot Insert Duplicate Primary Key

I am generating user Id in this way from controller

long lastUserId = 0;

var userProfile = from m in db.UserProfiles select m;
userProfile = userProfile.Where(s => s.DbType == "OFFLINE");

foreach (var c in userProfile)
{
   lastUserId = c.UserId;
}

if (lastUserId != 0)
{
   lastUserId = lastUserId + 1;
}
else
{
   lastUserId = 1000001;
}

When any two person register at same time and hit the controller I am getting the error of key violation now what to do?

Upvotes: 1

Views: 1270

Answers (4)

HCJ
HCJ

Reputation: 527

use 

static long lastUserId = 0;

Upvotes: 0

Amit
Amit

Reputation: 15387

I will suggest use primary key on that column that have IDENTITY, So you don't need to check.

if (lastUserId != 0)
{
   lastUserId = lastUserId + 1;
}
else
{
   lastUserId = 1000001;
}

It will automatically increase the value from the last one.

you can also define IDENTITY should be start from XYZ number and increase by 1 or as you want.

Each database support the IDENTITY feature.

Upvotes: 1

Bhupendra Shukla
Bhupendra Shukla

Reputation: 3914

Use a GUID for the Id or make the ID field Auto increment by taking BigInt at database and let Database to handle this. 

Guid lastUserId;
var userProfile = from m in db.UserProfiles select m;
userProfile = userProfile.Where(s => s.DbType == "OFFLINE");

foreach (var c in userProfile)
{
   lastUserId = c.UserId;
}

if (your condition)
{
   lastUserId = new Guid();
}

Upvotes: 1

Stan Smith
Stan Smith

Reputation: 906

Use a GUID for the Id if generating the identifier in code

or

Use your database... if you must use long type then the identifier field should be an auto-incrementing primary key which creates the unique numeric value at insertion (BIGINT type value for SQL Server.)

Upvotes: 0

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