Add {filename} for Tutorium 4

Tutorium_4_relationship in physical model

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+-- Example 1-to-1 relationship
+-- PK cntry.code is FK ppl.country
+SELECT cntry."name"
+		,cntry.capital
+		,ppl.population_growth
+	FROM "IDBS01_Q12025"."Country" cntry
+	INNER JOIN "IDBS01_Q12025"."Population" as ppl
+		ON cntry.code = ppl.country
+limit 10;
+
+
+-- Example 1-to-CN relationship
+-- PK cntry.code is FK brd.country1
+-- without mapping table
+SELECT *
+	FROM "IDBS01_Q12025"."Country" cntry
+	FULL OUTER JOIN "IDBS01_Q12025".borders brd
+		ON cntry.code = brd.country1
+	WHERE 1 = 1
+		--AND brd.country1 IS NULL
+		AND cntry.code IS NULL
+limit 10;
+
+-- Example 1-to-CN relationship
+--how to check if it is a 1-to-N relationship
+
+SELECT *
+	FROM "IDBS01_Q12025"."Country" cntry
+	LEFT JOIN "IDBS01_Q12025"."geo_Desert" gdsrt
+		ON cntry.code = gdsrt.country
+	LEFT JOIN "IDBS01_Q12025"."Desert" dsrt
+		ON gdsrt.desert = dsrt."name"
+limit 10;
+
+
+--Example N-to-CM relationship
+--with mapping table to N created by provicence
+
+SELECT gm.mountain
+		,count (1) AS Anzahl
+	FROM "IDBS01_Q12025"."Country" cntry
+	LEFT JOIN "IDBS01_Q12025"."geo_Mountain" gm
+		ON cntry.code = gm.country
+	group by gm.mountain
+	having count(1) > 1
+	order by 2 desc
+;
+
+SELECT *
+	FROM "IDBS01_Q12025"."geo_Mountain"
+	WHERE "geo_Mountain".mountain = 'Popocatepetl'
+limit 10;
+
+SELECT *
+	FROM "IDBS01_Q12025"."Country" cntry
+	INNER JOIN "IDBS01_Q12025"."Province" prv
+		ON cntry.code = prv.country
+	LEFT OUTER JOIN "IDBS01_Q12025"."geo_Mountain" gm
+		ON prv.country = gm.country
+			AND prv."name" = gm.province
+limit 10;