From 4b4b74fcb61ad6f071eca5bdd02427a72181fa88 Mon Sep 17 00:00:00 2001
From: Janis Hutz <development@janishutz.com>
Date: Wed, 24 Jun 2026 16:05:38 +0200
Subject: [PATCH] [DMDB] Basics of first and second normal form

---
 .../01_normal-forms/01_first-nf.tex                    | 10 ++++++++++
 .../01_normal-forms/02_second-nf.tex                   | 10 ++++++++++
 2 files changed, 20 insertions(+)

diff --git a/semester4/dmdb/parts/02_theory-background/01_normal-forms/01_first-nf.tex b/semester4/dmdb/parts/02_theory-background/01_normal-forms/01_first-nf.tex
index 02bb338..899b4e6 100644
--- a/semester4/dmdb/parts/02_theory-background/01_normal-forms/01_first-nf.tex
+++ b/semester4/dmdb/parts/02_theory-background/01_normal-forms/01_first-nf.tex
@@ -1 +1,11 @@
 \subsubsection{First Normal Form}
+In the first normal form, only atomic domains are allowed.
+
+\inlineintuition This makes the concept of a key easier to define, or well defined
+
+Some \sql\ flavours support arrays. However, the semantics and the support varies
+
+This can come in handy to solve one to many relationships, but what if many different persons have the same elements there?
+This can cause some issues when updating.
+
+Arrays are very tempting to use if we have an unknown and variable number of different data points for a field.
diff --git a/semester4/dmdb/parts/02_theory-background/01_normal-forms/02_second-nf.tex b/semester4/dmdb/parts/02_theory-background/01_normal-forms/02_second-nf.tex
index e69de29..40a3a5b 100644
--- a/semester4/dmdb/parts/02_theory-background/01_normal-forms/02_second-nf.tex
+++ b/semester4/dmdb/parts/02_theory-background/01_normal-forms/02_second-nf.tex
@@ -0,0 +1,10 @@
+\subsection{Second Normal Form}
+The two dependencies $\{ \text{Legi}, \text{Nr} \} \rightrightarrow \{ \text{Name}, \text{Semester} \}$,
+$\{ \text{Legi} \} \rightrightarrow \{ \text{Name}, \text{Semester} \}$ state the following:
+
+\begin{itemize}
+    \item Legi determines the name and semester of a student.
+    \item The first map has to happen, even though mapping $\{ \text{Legi}, \text{Nr} \}$ to $\{ \text{Legi} \}$ would be enough. We thus will have redundancy.
+          However, this is the exact relationship that the table is meant to capture
+          Thus, $\{ \text{Name}, \text{Semester} \}$ should not be in the table at all.
+\end{itemize}