database normalization first normal form confusion - when should separating tables out -


please consider academic view not practical engineering view. 1nf , 1nf only.

considering unnormalized form below, primary key {trainingdatetime, employeenumber}, how make first normal form?

if separate course, instructor , employee tables out separate tables, automatically become 3nf.

unf!

if split different rows, like:

enter image description here

but problem here obvious - primary key no longer valid.

changing primary key {trainingdatetime, employeenumber, employeeskill} doesn't seems sensible solution.

just make satisfy 1nf, need have seperate rows individual teaching skills. should ensuring higher normal forms satisfied splitting tables. 1 row should have teaching skill advanced php , second row advanced java , third row advanced sql , on same employee.


Comments

Post a Comment

Popular posts from this blog

asp.net mvc - SSO between MVCForum and Umbraco7 -

i need integrate sso between mvcforum (forum of company) , umbraco7 (manages cms company). however struggling shared authentication work. tried several ways suggested on other threads still not running expected. here did: 1. in mvcforum (forum.mywebsite.com) 1.1. machine key in web.xml: <machinekey validationkey="the same key umbraco7" decryptionkey="the same key umbraco7" validation="sha1" decryption="aes" /> 1.2. authenticate forms in web.xml <forms name="my-sso-auth" protection="all" path="/" timeout="43200" domain="forum.mywebsite.com" loginurl="/members/logon" enablecrossappredirects="true" /> 2. in umbraco7 (news.mywebsite.com) 2.1. machine key in web.xml: <machinekey validationkey="the same key mvcforum" decryptionkey="the same key mvcforum" validation="sha1" decryption="aes" /> 2.2. a
Read more

Python Tkinter keyboard using bind -

i have problem using bind option can click button in keyboard, , call function once key pressed. tried taking other codes have similar purpose , saw i'm doing pretty same, though still have problem must've missed. thankful if me this. here's code: # -*- coding: utf-8 -*- #imports tkinter import * pil import imagetk, image import time import tkmessagebox #===========================================================================================================================================# #tkinter class class app(frame): def __init__(self, master=none): frame.__init__(self, master) self.pack() #===========================================================================================================================================# #game pieces classes class board: def __init__(self, rows = 7, columns = 6, picture_height = none, picture_width = none): self.rows = rows self.columns = columns self.picture
Read more

ubuntu - Selenium Node Not Connecting to Hub, Not Opening Port -

i'm trying set demo selenium grid. have digital ocean ubuntu 14.02 droplet. (i have 2 , tried set using 2 different machines got nowhere.) i'm trying run hub , node both locally. here input both hub, node, , nmap results. https://gist.github.com/mekhami/d5bbecca5ff0de9d2dc9 so, node starting tcp connection reset , port it's supposed operate on closed. i have had no luck in number of different options , configurations work. but... of course, worked randomly once. don't know why, don't know did, know 1 brief moment, node connected , saw on grid console. tried run test , went down again , i've never seen come up. please let me know more information can provide. update: randomly came online again. don't know happened, might related timeout or time_wait or going on. this because vm/server not have enough entropy available. to resolve problem, install haveged (or other similar things). the instructions of how install haveged on ubu
Read more