SQL_RelationalAlg

Question 1

Is SQL case sensitive?

Answer 1

Case convention
• SQL is completely case insensitive.
Upper-case or Lower-case makes no
difference. We will use case in the
following way:
– UPPERCASE marks keywords of the SQL
language.
– lowercase marks the name of an attribute.
– Capitalized marks the name of a table.

Question 2

Question 3

How to Create and Drop Tables?

Answer 3

Question 4

What are Table declaration elements?

Answer 4

Question 5

Why add NOT NULL when creating tables?

Answer 5

Question 6

How to declare keys?

Answer 6

Question 7

How to add Primary Key SQL?

Answer 7

Question 8

How to code foreign keys?

Answer 8

Question 9

Rules concerning Foregin Keys.

Answer 9

Question 10

Code in SQL.

Answer 10

Question 11

Another Example

Answer 11

Question 12

How to use value constraints?

Answer 12

Question 13

Add value constraint that the period is an INT for period 1:4.

Answer 13

Question 14

Another Check Constraint for the Period being an INT of values 1-4.

Answer 14

Question 15

How to insert data to this table?

Answer 15

Question 16

Why is one of those illegal?

CREATE TABLE GivenCourses (
course CHAR(6) REFERENCES Courses,
period INT CHECK (period IN (1,2,3,4)),
numStudents INT,
teacher INT REFERENCES People(ssn) NOT
NULL,
PRIMARY KEY (course, period)
);

Answer 16

Question 17

How to Delete rows from Table.

Answer 17

Question 18

How to update tables.

Answer 18

Question 19

What is a Query? What is the difference between query and modifications?

Answer 19

Question 20

What does SQL means?

Answer 20

Question 21

How is Algebra defined in this context?

Answer 21

Question 22

What is relational algebra?

Answer 22

Question 23

Explain Selection (Relational Algebra).

Answer 23

Question 24

Which operations is denoted with a sigma?

Answer 24

Question 25

Answer 25

Question 26

Explain Projection (Relational Algebra).

Answer 26

Question 27

Which operation is denoted with a pi?

Answer 27

Question 28

Answer 28

Question 29

Answer 29

Question 30

Answer 30

Question 31

Answer 31

Question 32

Answer 32

Question 33

What are Cartesian Products?

Answer 33

Question 34

Answer 34

Question 35

What are Joining relations?

Answer 35

Question 36

What does this symbol represent?

Answer 36

Question 37

Answer 37

Question 38

Explain Natural Join.

Answer 38

Question 39

What does this specific symbol represent?

Answer 39

Question 40

Answer 40

Question 41

Explain Sets or Bags.

Answer 41

Question 42

Differences between sets and bags?

Answer 42

Question 43

Method for selecting from a specific table with conditions.

Answer 43

Question 44

How does query result look?

Answer 44

Question 45

Translate to Relation Algebra Expression.

Answer 45

Question 46

Translate.

Answer 46

Question 47

Translate to Relational Algebra.

Answer 47

Question 48

Translate.

Answer 48

Question 49

Answer 49

Question 50

Translate.

Answer 50

Question 51

Explain Subqueries.

Answer 51

Question 52

Answer 52

Question 53

Why renaming attributes?

Answer 53

Question 54

Why renaming relations?

Answer 54

Question 55

Answer 55

Question 56

Explain Renaming in Relational Algebra.

Answer 56

Question 57

Explain the following expression.

Answer 57

Question 58

Explain Sequencing.

Answer 58

Question 59

Answer 59

Question 60

Explain views.

Answer 60

Question 61

Create a view DBLectures containing room, weekday and hour from the table Lectures. The course should be TDA357 and the period should be 3. Then query the weekday from the view based on the room HC1.

Answer 61

Question 62

Explain the WHERE clause.

Answer 62

Question 63

How to test for membership.

Answer 63

Question 64

What does this mean?

Answer 64

Question 65

Answer 65

Question 66

How do you test for existence?

Answer 66

Question 67

What does this mean?

Answer 67

Question 68

What is a correlated query?

Answer 68

Question 69

Answer 69

Question 70

What are ordinary comparisons?

Answer 70

Question 71

Meaning?

Answer 71

Question 72

How to do comparisons with many rows?

Answer 72

Question 73

What does this mean?

Answer 73

Question 74

Answer 74

Question 75

What are string comparisons?

Answer 75

Question 76

Answer 76

Question 77

What does the NULL symbol means?

Answer 77

Question 78

Can you compare values with NULL?

Answer 78

Question 79

Explain three-valued logic.

Answer 79

Question 80

Results?

Answer 80

Question 81

What does it mean with don't expect usual results with three-valued logic?

Answer 81

Question 82

E-R diagram?

Answer 82

Question 83

Which Approach?

Answer 83

Question 84

Which Approach?

Answer 84

Question 85

Schema?

Answer 85

Question 86

Schema?

Answer 86

Question 87

E-R?

Answer 87

Question 88

E-R?

Answer 88

Question 89

Schema?

Answer 89

Question 90

E-R?

Answer 90

Question 91

Schema?

Answer 91

Question 92

Wrong?

Answer 92

Question 93

Wrong?

Answer 93

Question 94

Wrong?

Answer 94

Question 95

Answer 95

Question 96

Can Constants be used in Projections?

Answer 96

Question 97

Explain Aggregation.

Answer 97

Question 98

What will happen?

Answer 98

Question 99

Answer 99

Question 100

Answer 100

Question 101

Answer 101

Question 102

What will happen?

Answer 102

Question 103

Answer 103

Question 104

What will happen?

Answer 104

Question 105

Answer 105

Question 106

What does single-value query means?

Answer 106

Question 107

NULL in aggregations?

Answer 107

Question 108

Query for capacity at campus?

Answer 108

Question 109

Meaning?

Answer 109

Question 110

Explain Grouping.

Answer 110

Question 111

Explain Grouping in terms of Relational Algebra.

Answer 111

Question 112

Symbol represents?

Answer 112

Question 113

Answer 113

Question 114

Answer 114

Question 115

Explain specialized renaming of attributes.

Answer 115

Question 116

What does this represents?

Answer 116

Question 117

Explain Tests on Groups.

Answer 117

Question 118

Resultat?

Answer 118

Question 119

Answer 119

Question 120

Relational Algebra Translation?

Answer 120

Question 121

Translation?

Answer 121

Question 122

Explain Sorting Relations.

Answer 122

Question 123

What does this represents?

Answer 123

Question 124

What will happen?

Answer 124

Question 125

Describe full structure of SQL query.

Answer 125

Question 126

Translate to relational alebgra.

Answer 126

Question 127

Translate to SQL query.

Answer 127

Question 128

Relational Algebra Expression?

Answer 128

Question 129

SQL expression?

Answer 129

Question 130

Results?

Answer 130

Question 131

Results?

Answer 131

Question 132

Relational Algebra Expression?

Answer 132

Question 133

SQL Expression?

Answer 133

Question 134

Answer 134

Question 135

Explain Lexical vs Logical ordering.

Answer 135

Question 136

What are Available attributes in SELECT?

Answer 136

Question 137

Valid/Invalid.

Answer 137

Question 138

Valid/Invalid?

Answer 138

Question 139

Valid/Invalid?

Answer 139

Question 140

Answer 140

Question 141

Answer 141

Question 142

Answer 142

Question 143

Write Symbols for: Select Project Rename Union

Answer 143

Question 144

Write symbols for: Intersection Difference Cross Product Join

Answer 144

Question 145

Write symbols for: Natural Join Division Grouping

Answer 145

Question 146

Difference between Selection and Projection?

Answer 146

Question 147

Left Outer Join?

Answer 147

Question 148

Right Outer Join?

Answer 148

Question 149

Full Outer Join?

Answer 149

Question 150

Which modifications can be made to the database?

Answer 150

Modifying the contents of a database: – Insertions INSERT INTO tablename VALUES tuple – Deletions DELETE FROM tablename WHERE test over rows – Updates UPDATE tablename SET attribute = value WHERE test over rows

Question 151

Explain Insertions with Queries.

Answer 151

Question 152

What are Explicit Attributes?

Answer 152

Question 153

Answer 153

Question 154

Describe how SQL handles Default Values.

Answer 154

Question 155

Explain Insertion with Default Values.

Answer 155

Question 156

Answer 156

Question 157

Explain Policies for updates and deletions.

Answer 157

Question 158

Explain Cascading.

Answer 158

Question 159

Explain Set NULL.

Answer 159

Question 160

Answer 160

Question 161

Explain Single-attribute constraints.

Answer 161

Question 162

Explain how to specificy that a value must be non NULL

Answer 162

Question 163

Explain a Special Case of References.

Answer 163

Question 164

Answer 164

Question 165

Which are the different types of constraints?

Answer 165

Question 166

Answer 166

Question 167

Explain Triggers.

Answer 167

Question 168

Explain Assertions as Triggers.

Answer 168

Question 169

Explain the basic Trigger structure.

Answer 169

Question 170

Explain Stored Procedures.

Answer 170

Question 171

What does NEW in Triggers refer to?

Answer 171

Question 172

Example of Trigger structure.

Answer 172

Question 173

Explain Trigger events.

Answer 173

Question 174

What does FOR EACH ROW mean?

Answer 174

Question 175

Explain Trigger Conditions.

Answer 175

Question 176

Answer 176

Question 177

Explain views.

Answer 177

Question 178

Elaborate on updating Views.

Answer 178

Question 179

Explain Triggers on Views.

Answer 179

Question 180

Summarize Triggers.

Answer 180