Update the inserted record in ASP.NET web API project

In my project I am inserting an employee and as my employee is inserted my save button HTML turns to update and on the back-end I am using the same insert function for updating the employee which I just inserted, my insert functionality is working perfectly but as I attempt to update the same record it inserts a new record in database instead of updating the data against the inserted ID, how do I update the existing or currently inserted user against their respective IDs.

I do not know why my update is not working and why I am not able to update right after inserting the user, every time I try to update the user I end up inserting the user again, and how should I restrict my application from inserting similar data again and again, the insert and update button are the same, as I mentioned above that on inserting the user I am changing the inner HTML of my button from save to update and using that same button to update 

Here is my complete code, please let me know If I am making any mistakes at any part of my code, all the help I get from you guys is highly appreciated


In my HTML on top of my input fields I am storing the currently inserted user ID in a hidden field like this

    <input type="hidden" class="HiddenID" />

I do not know how to use this hidden field ID for updating the User right after inserting, because as I mentioned my insert and update functions both lies on same button


all help is highly appreciated, please let me know where I am wrong
happy coding

My stored procedure code:

    ALTER PROCEDURE [dbo].[sp_InsEmpOfficialDetails] 
        (@EmpID int = NULL,
    	 @UserName varchar(500) = NULL,
    	 @pass varchar(500) = NULL,
    	 @OfficialEmailAddress varchar(500) = NULL,
      	 @Department varchar(500) = NULL,
    	 @RoleID int = NULL,
    	 @Role varchar(500) = NULL,
    	 @IsAdmin bit = NULL,
    	 @Designation varchar(500) = NULL,
    	 @ReportToID int = NULL,
    	 @ReportTo varchar(500) = NULL,
    	 @JoiningDate datetime = NULL,
    	 @IsPermanent bit = NULL,
     	 @DateofPermanancy datetime = NULL,
    	 @IsActive bit = NULL,
    	 @HiredbyReference bit = NULL,
    	 @HiredbyReferenceName varchar(500) = NULL,
    	 @BasicSalary int = NULL,
    	 @CurrentPicURL nvarchar(max) = NULL
     	 -- @CreatedBy int,									
    	 -- @CreatedOn datetime,				
    	 -- @UpdatedOn datetime,								
    	 -- @UpdatedBy int 									
        )
    AS
    BEGIN
        IF EXISTS (SELECT 1 FROM Employee 
               	   WHERE UserName = @UserName
                  	 AND pass = @pass
                  	 AND OfficialEmailAddress = @OfficialEmailAddress
    	             AND Department = @Department
    	             AND RoleID = @RoleID
    	             AND Role = @Role
    	             AND IsAdmin = @IsAdmin
    	             AND Designation = @Designation
    	             AND ReportToID = @ReportToID
    	             AND ReportTo = @ReportTo
    	             AND JoiningDate = @JoiningDate
    	             AND IsPermanent = @IsPermanent
    	             AND DateofPermanancy = @DateofPermanancy
    	             AND IsActive = @IsActive
    	             AND HiredbyReference = @HiredbyReference
    	             AND HiredbyReferenceName = HiredbyReferenceName
    	             AND BasicSalary = @BasicSalary
    	             AND CurrentPicURL = @CurrentPicURL)
    	BEGIN
    		UPDATE Employee
    		SET UserName = @UserName,
    	     	pass = @pass,
        		OfficialEmailAddress = @OfficialEmailAddress,
        		Department = @Department,
         		RoleID = @RoleID,
        		Role = @Role,
        		IsAdmin = @IsAdmin,
        		Designation = @Designation,
        		ReportToID = @ReportToID,
        		ReportTo = @ReportTo,
        		JoiningDate = @JoiningDate,
        		IsPermanent = @IsPermanent,
        		DateofPermanancy = @DateofPermanancy,
        		IsActive = @IsActive,
        		HiredbyReference = @HiredbyReference,
        		HiredbyReferenceName = HiredbyReferenceName,
        		BasicSalary = @BasicSalary,
        		CurrentPicURL = @CurrentPicURL
    		WHERE EmpID = @EmpID
    	END
        ELSE
    	BEGIN
    		SET NOCOUNT ON;

        INSERT INTO Employee(UserName, pass,
    OfficialEmailAddress,Department,
    RoleID, Role, IsAdmin, Designation,
    ReportToID, ReportTo, JoiningDate,
    IsPermanent, DateofPermanancy, IsActive,
    HiredbyReference, HiredbyReferenceName,
    BasicSalary, CurrentPicURL)
    		VALUES (@UserName, @pass, @OfficialEmailAddress, @Department,
    		        @RoleID, @Role, @IsAdmin, @Designation,
    		        @ReportToID, @ReportTo, @JoiningDate,
    		        @IsPermanent, @DateofPermanancy, @IsActive,
    		        @HiredbyReference, @HiredbyReferenceName,
    		        @BasicSalary, @CurrentPicURL)
    		SELECT SCOPE_IDENTITY();
    	END
    END

My ajax code:

    $('.empOfficialDetails').click(function (ev) {
        ev.preventDefault();

        var data = new Object();
        data.UserName = $('#username').val();
        data.UPassword = $('#userpass').val();
        data.OfficialEmailAddress = $('#officialemail').val();
        data.Departments = $('#departments :selected').text();
        data.Designation = $('#designation :selected').text();
        data.RoleID = $('#role').val();
        data.Role = $('#role :selected').text();
        data.ReportToID = $('#reportToID').val();
        data.ReportTo = $('#reportTo :selected').text();
        data.JoiningDate = $('#joindate').val();
        data.IsAdmin = $('#isAdmin :selected').val() ? 1 : 0;
        data.IsActive = $('#isActive :selected').val() ? 1 : 0;
        data.IsPermanent = $('#isPermanent :selected').val() ? 1 : 0;
        data.DateofPermanancy = $('#permanantdate').val();
        data.HiredbyReference = $('#hiredbyRef :selected').val() ? 1 : 0;
        data.HiredbyReferenceName = $('#refePersonName').val();
        data.BasicSalary = $('#basicSalary').val();
        data.CurrentPicURL = $('.picture').val();
        //data.CurrentPicURL = $('.picture')[0].files;

        if (data.UserName && data.UPassword && data.OfficialEmailAddress && data.Departments && data.Designation && data.Role && data.IsAdmin && data.IsPermanent) {
            $.ajax({
                url: 'http://localhost:1089/api/Employee/EmpOfficialDetails',
                type: "POST",
                dataType: 'json',
                contentType: "application/json",
                data: JSON.stringify(data),
                enctype: 'multipart/form-data',
                beforeSend: function () {
                    $("#dvRoomsLoader").show();
                },
                complete: function () {
                    $("#dvRoomsLoader").hide();
                },
                success: function (data) {
                    var ID = parseInt(data);
                    if (ID > 0) {
                        //var id = data;
                        $(".HiddenID").val(data);
                        //var id = $(".HiddenID").val();
                        $('#official').css('display', 'block');
                        $('#official').html("Employees Official details added successfully...!");
                        $('#official').fadeOut(25000);
                        $("#dvRoomsLoader").show();

                        $('.empOfficialDetails').html("Update   ">");
                    }
                    else {
                        $('#official').find("alert alert-success").addClass("alert alert-danger").remove("alert alert-success");
                    }
                },
                error: function (ex) {
                    alert("There was an error while submitting employee data");
                    alert('Error' + ex.responseXML);
                    alert('Error' + ex.responseText);
                    alert('Error' + ex.responseJSON);
                    alert('Error' + ex.readyState);
                    alert('Error' + ex.statusText);
                }
            });
            
        }
        return false;

    });

my controller code:

    public int Emp_OfficialDetails(Employee emp)
        {
            //SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["AmanraHRMS"].ConnectionString);
            var con = DB.getDatabaseConnection();
            SqlCommand com = new SqlCommand("sp_InsEmpOfficialDetails", con);
            com.CommandType = CommandType.StoredProcedure;

            #region Employee Official Details Insert Code block

            com.Parameters.AddWithValue("@UserName", emp.UserName);
            com.Parameters.AddWithValue("@pass", emp.UPassword);
            com.Parameters.AddWithValue("@OfficialEmailAddress", emp.OfficialEmailAddress);
            com.Parameters.AddWithValue("@Department", emp.Departments);
            com.Parameters.AddWithValue("@Role", emp.Role);
            com.Parameters.AddWithValue("@IsAdmin", Convert.ToBoolean(emp.IsAdmin));
            com.Parameters.AddWithValue("@Designation", emp.Designation);
            com.Parameters.AddWithValue("@ReportToID", emp.ReportToID);
            com.Parameters.AddWithValue("@ReportTo", emp.ReportTo);
            com.Parameters.AddWithValue("@JoiningDate", Convert.ToDateTime(emp.JoiningDate));
            com.Parameters.AddWithValue("@IsPermanent", Convert.ToBoolean(emp.IsPermanent));
            com.Parameters.AddWithValue("@DateofPermanancy", Convert.ToDateTime(emp.DateofPermanancy));
            com.Parameters.AddWithValue("@IsActive", Convert.ToBoolean(emp.IsActive));
            com.Parameters.AddWithValue("@HiredbyReference", Convert.ToBoolean(emp.HiredbyReference));
            com.Parameters.AddWithValue("@HiredbyReferenceName", emp.HiredbyReferenceName);
            com.Parameters.AddWithValue("@BasicSalary", emp.BasicSalary);
            com.Parameters.AddWithValue("@CurrentPicURL", emp.CurrentPicURL);

            #endregion
            //var file = emp.CurrentPicURL;

            //EmployeeImage(file);

            var ID = com.ExecuteScalar();
            com.Clone();
            return Convert.ToInt32(ID);
        }

        //Ajax call hit this method from AddEmployee page
        [Route("api/Employee/EmpOfficialDetails")]
        [HttpPost]
        public int? EmpOfficialDetails(Employee emp)
        {
            IHttpActionResult ret;
            try
            {
                var id = Emp_OfficialDetails(emp);
                return id;
            }
            catch (Exception ex)
            {
                ret = InternalServerError(ex);
            }
            return null;
        }