diff --git a/semester4/dmdb/data-modelling-databases-summary.pdf b/semester4/dmdb/data-modelling-databases-summary.pdf
index 1eea2a2..a0e614a 100644
Binary files a/semester4/dmdb/data-modelling-databases-summary.pdf and b/semester4/dmdb/data-modelling-databases-summary.pdf differ
diff --git a/semester4/dmdb/parts/05_concurrency-control-recovery/02_transaction-model.tex b/semester4/dmdb/parts/05_concurrency-control-recovery/02_transaction-model.tex
index 394d411..113db6c 100644
--- a/semester4/dmdb/parts/05_concurrency-control-recovery/02_transaction-model.tex
+++ b/semester4/dmdb/parts/05_concurrency-control-recovery/02_transaction-model.tex
@@ -24,7 +24,7 @@ So, we have the following statements:
 Below a list of very important syntax for the exam (where the subscript $i$ denotes that this operation is part of transaction $T_i$):
 \begin{itemize}
     \item Read operations: $r_i[x]$ or $r_i(x)$ is an access to tuple $x$ without modifying it.
-    \item Write operations: $w_i[x]$ or $r_i(x)$ represents a write operation on the tuple $x$.
+    \item Write operations: $w_i[x]$ or $w_i(x)$ represents a write operation on the tuple $x$.
     \item Abort: $a_j$ is an abort of transaction $T_j$
     \item Commit $c_j$ is the commit of transaction $T_j$
 \end{itemize}