From c954caae46263ec9fe6290bd45f921d0b3ca3a16 Mon Sep 17 00:00:00 2001
From: Julian T <julian@jtle.dk>
Date: Thu, 18 Nov 2021 11:49:29 +0100
Subject: Add exercises for db 10

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 sem7/db/opg10.md | 191 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 191 insertions(+)
 create mode 100644 sem7/db/opg10.md

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+# Exercise 1
+
+**A)** Hvis vi gerne må hente ting fra Shop, kan vi løse det med en join.
+
+```sql
+SELECT State, SUM(Count)
+FROM TotalSales, Shop
+WHERE TotalSales.ShopID = Shop.ShopID
+GROUP BY State
+```
+
+**B)** Det kan vi ikke, da vi skal bruge MAX(price) hvilket man ikke kan få fra SUM(price).
+
+**C)** Nej det kan vi ikke, fordi TotalSales ikke har DayID. Den har bare Total over altid.
+
+**D)** Men den her kan vi godt.
+
+```sql
+SELECT State, Genre, SUM(Price), SUM(Count)
+FROM TotalSales, Book, Shop
+WHERE TotalSales.ShopID = Shop.ShopID AND TotalSales.BookID = Book.BookID
+GROUP BY State, Genre
+```
+
+# Exercise 2
+
+Gender=Male    : 1100101
+Gender=Female  : 0011010
+Office=London  : 1001100
+Office=Glasgow : 0100010
+Office=Cardiff : 0010001
+Title=Dev      : 1010011
+Title=Tester   : 0101000
+Title=Man      : 0000100
+
+**A)**
+
+And 0011010 
+med 1010011
+  = 0010010
+
+Så det er row 3, 6
+
+**B)**
+
+Not 0010001
+  = 1101110
+
+Så det er row 1, 2, 4, 5, 6
+
+**C)**
+
+And 1101110
+med 0011010
+  = 0001010
+
+Så det er row 4, 6
+
+**D)**
+
+And 1010011
+med 1001100
+  = 1000000
+
+Det er row 1
+
+# Exercise 3
+
+Det vil ikke give så meget mening at have 3000 forskellige indexes.
+Hvis der for eksempel kun er 300 mennesker, vil det slet ikke give mening.
+
+**B)**
+
+[0;1000)   : 10100000
+[1000;2000): 01001010
+[2000;3000): 00010101
+
+**C)**
+
+Ja indexen kan hjælpe, men man skal have et refinement step.
+Man starter med at finde alle i [1000;3000), også kan man sortere resten fra manuelt.
+
+# Exercise 4
+
+Step 0: A
+
+B: 4 * 200 = 800
+C: 4 * 520 = 2080
+D: 4 * 100 = 400
+E: 2 * 580 = 1160
+F: 2 * 595 = 1190
+G: 2 * 590 = 1180
+H: 1 * 599 = 599
+Step 1: C
+Step 2: G
+Step 3: B
+
+Space: 600 + 80 + 10 + 400 = 1090
+Time: 
+A = 0
+B = 0
+C = 0
+D = 600
+E = 80
+F = 80
+G = 0
+H = 10
+Total: 600 + 80 + 80 + 10 = 770
+
+# Exercise 5
+
+**A)**
+
+1(1)
+2(1)
+7(1)
+
+**B)**
+
+1(1)
+2(1)
+7(1)
+3(2)
+
+**C)**
+
+1(1)
+2(1)
+7(1)
+3(2)
+4(1)
+
+**D)**
+
+1(1)
+2(1)
+3(2)
+4(1)
+
+# Exercise 6
+
+**A)**
+<g, sum, count>
+
+alpha, 100, 3
+beta,  40,  1
+gamma, 25,  2
+delta, 10,  1
+
+**B)**
+
+alpha, 100, 3
+beta,  0,   2
+gamma, 25,  2
+delta, 10,  1
+
+**C)**
+
+alpha, 100, 3
+beta,  0,   2
+gamma, 35,  3
+delta, 10,  1
+
+**D)**
+
+alpha, 100, 3
+beta,  0,   2
+gamma, 15,  1
+
+**E)**
+
+alpha, 100, 3
+beta,  0,   2
+gamma, 15,  1
+epsilon, 0, 1
+
+# Exercise 7
+
+Gender=Male    : 1100101
+Gender=Female  : 0011010
+Office=London  : 1001100
+Office=Glasgow : 0100010
+Office=Cardiff : 0010001
+Title=Dev      : 1010011
+Title=Tester   : 0101000
+Title=Man      : 0000100
+
+Glasgow : 01,101
+Man     : 11000
+Male    : 00,00,100,01
+
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