multithreading - Confused with MS SQL Server LOCK would help in INSERT Scenario.(Concurrency) -

business scenario: ticketing system, , got many user using application. when ticket(stored in 1st table in below) comes in application, user can hit ownership button , take ownershipf of it. 1 user can take ownership 1 ticket. if 2 user tries hit ownership button, first 1 wins , second gets incident or message no incident exists take ownership. here facing concurrency issue now. have lock implementation using table(2nd table in below).

i have 2 tables;

table(columns)

1. ticket(ticketid-pk, owneruserid-fk)
2. ticketownershiplock(ticketid-pk, owneruserid-fk, lockdate)note: here ticketid set primary key.

current lock implementation: whenever user 1 tries own ticket puts entry 2nd table ticketid, userid , current date,then goes update owneruserid in 1st table. before insert above said lock entry, procedure checks other user created lock same incident. if there lock, lock wont opened user. else lock entry wont entered , user cannot update ticket onwership. more info: there many tickets getting opened in 1st table, whenever user tries take ownership, should find next available ticket take ownership. need find ticket , calculation , set status ticket, there 1 more column in 1st table statusid. status assigned assigned.

problem: somehow 2 user's got ownership same ticket @ excatly same time, have checked millisecond same. 1. know if ms sql server lock in scenario. 2. or need block table while insert.(this 2nd rable not have data approx. less 15 rows)

lock creation procedure below:

alter procedure [dbo].[takeownershipgetlock]      @ticketid [uniqueidentifier],     @ownerid [uniqueidentifier] begin      set nocount on;      begin transaction takeownership     begin try          declare @lock bit         set @lock = 0          declare @lockdate datetime          select  @lockdate = lockdate            dbo.takeownershiplock           ticketid = @ticketid          if @lockdate null             , not exists ( select 1                                   dbo.takeownershiplock takeownership (updlock)                                 inner join dbo.ticket ticket (nolock)                                 on ticket.ticketid = takeownership.ticketid                                  takeownership.ticketid = @ticketid                                 , ticket.ownerid null )             begin                 insert  dbo.takeownershiplock                         ( ticketid                         ,ownerid                         ,lockdate                         )                 values  ( @ticketid                         ,@ownerid                         ,getdate()                         )                  if ( @@rowcount > 0 )                     set @lock = 1             end          select  @lock          commit transaction takeownership     end try     begin catch         -- test whether transaction uncommittable.         if xact_state() = 1             begin                 commit transaction takeownership                 set @lock = 1                 select  @lock             end            -- test whether transaction active , valid.            if xact_state() = -1             begin                 rollback transaction takeownership                 set @lock = 0                 select  @lock             end          end catch end