Big Data 12. Querying

Transcription

1 Ghislain Fourny Big Data 12. Querying pinkyone / 123RF Stock Photo

2 Declarative Languages What vs. How 2

3 Functional Languages for let order by if + any else = then every while where return exit with Expression 3

4 Ever played Lego? 4

5 Ever played Lego? if( ) then else 5

6 Ever played Lego? if( ) my:func( ) then else 6

7 Ever played Lego? if( ) my:func( ) then else 7

8 Ever played Lego? if( ) my:func( ) 2 then else 8

9 Ever played Lego? if( ) my:func( ) 2 then for $x in let $y := return else 9

10 Ever played Lego? if( ) my:func( ) 2 then for $x in let $y := return else 10

11 Ever played Lego? if( ) my:func( ) 2 then for $x in let $y := return else 11

12 Language ecosystem XML JSON Navigation XPath JSONPath JSONSelect 12

13 Language ecosystem XML JSON Navigation XPath JSONPath JSONSelect Transform XSLT JSONT 13

14 Language ecosystem XML JSON Navigation XPath JSONPath JSONSelect Transform XSLT JSONT Query XQuery 1.0/3.0 XQuery 3.1, JSON Query, JSONiq 14

15 Language ecosystem XML JSON Navigation XPath JSONPath JSONSelect Transform XSLT JSONT Query XQuery 1.0/3.0 XQuery 3.1, JSON Query, JSONiq Update, Scripting XQuery Update Facility & Scripting JSONiq 15

16 Try it out! 16

17 XML Navigation (XPath, XQuery) 17

18 The slash operator <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">& &&&&<name>switzerland</name>& &&</country>& &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& & doc("myfile.xml")/countries/country/name 18

19 The slash operator <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">&!!!!<name>switzerland</name>! &&</country>& &&<country&code="f">&!!!!<name>france</name>! &&</country>& &&<country&code="d">&!!!!<name>germany</name>! &&</country>& &&<country&code="i">&!!!!<name>italy</name>! &&</country>& &&<country&code="a">&!!!!<name>austria</name>! &&</country>& </countries>& & doc("myfile.xml")/countries/country/name 19

20 Axis <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">&!!!!<name>switzerland</name>! &&</country>& &&<country&code="f">&!!!!<name>france</name>! &&</country>& &&<country&code="d">&!!!!<name>germany</name>! &&</country>& &&<country&code="i">&!!!!<name>italy</name>! &&</country>& &&<country&code="a">&!!!!<name>austria</name>! &&</country>& </countries>& & doc("myfile.xml") /child::countries /child::country /child::name 20

21 Axis <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">&!!!!<name>switzerland</name>! &&</country>& &&<country&code="f">&!!!!<name>france</name>! &&</country>& &&<country&code="d">&!!!!<name>germany</name>! &&</country>& &&<country&code="i">&!!!!<name>italy</name>! &&</country>& &&<country&code="a">&!!!!<name>austria</name>! &&</country>& </countries>& & doc("myfile.xml") /descendant::country /child::name 21

22 All Axes Forward Axes self:: attribute:: child:: descendant:: descendant-or-self:: following-sibling:: following:: Reverse Axes parent:: ancestor:: ancestor-or-self:: preceding-sibling:: preceding:: 22

23 Axis <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">& &&&&<name>switzerland</name>& &&</country>& &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& doc("myfile.xml") /descendant::country /child::name 23

24 Axis <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">& &&&&<name>switzerland</name>& &&</country>& &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& doc("myfile.xml") /descendant::country /attribute::code/data() 24

25 Attribute Abbreviation <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">& &&&&<name>switzerland</name>& &&</country>& &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& doc("myfile.xml") /descendant::country 25

26 Descendant-or-self Abbreviation <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">& &&&&<name>switzerland</name>& &&</country>& &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& doc("myfile.xml") //country 26

27 Filters <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">& &&&&<name>switzerland</name>& &&</country>& &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& & doc("myfile.xml") /descendant::country eq "CH"] 27

28 Implicit Context Item <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">& &&&&<name>switzerland</name>& &&</country>& &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& & doc("myfile.xml") /descendant::country eq "CH"] 28

29 Joker <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country)code="ch">) ))))<name>switzerland</name>) ))</country>) &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& & doc("myfile.xml") /descendant::country eq "CH"] /parent::* 29

30 Parent Abbreviation <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country)code="ch">) ))))<name>switzerland</name>) ))</country>) &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& & doc("myfile.xml") /descendant::country eq "CH"] /.. 30

31 Alternative <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country)code="ch">) ))))<name>switzerland</name>) ))</country>) &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& & doc("myfile.xml") /descendant::country eq "CH"] 31

32 Atomization <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country)code="ch">) ))))<name>switzerland</name>) ))</country>) &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& & doc("myfile.xml") /descendant::country eq "CH"] 32

33 Atomization <name>switzerland</name>0 <name>france</name>0 <name>germany</name>0 <name>italy</name>0 <name>austria</name>0 0 data( ) Switzerland, France, Germany, Italy, Austria, 33

34 Kind test <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">&!!!!<name>switzerland</name>! &&</country>& &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& & doc("myfile.xml") /descendant::country eq "CH"] /child::element() 34

35 All Kinds Simplest document-node() element() attribute() text() comment() processing-instruction() namespace-node() More precise document-node(element(countries)) element(countries) element(name, xs:string) schema-element(country) attribute(*, xs:integer) schema-attribute(code) processing-instruction(excel) 35

36 Kind test <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">&!!!!<name>switzerland</name>! &&</country>& &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& & doc("myfile.xml") /descendant::country eq "CH"] /element() 36

37 Simpler <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">&!!!!<name>switzerland</name>! &&</country>& &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& & doc("myfile.xml") /descendant::country eq "CH"] /name 37

38 Continued <?xml&version="1.0"&encoding="utf98"?>& <countries>& &&<country&code="ch">& &&&&<name>switzerland</name>& &&</country>& &&<country&code="f">& &&&&<name>france</name>& &&</country>& &&<country&code="d">& &&&&<name>germany</name>& &&</country>& &&<country&code="i">& &&&&<name>italy</name>& &&</country>& &&<country&code="a">& &&&&<name>austria</name>& &&</country>& </countries>& & doc("myfile.xml") /descendant::country eq "CH"] /name/data() 38

39 Construction (XPath, XQuery) 39

40 Construction: Strings "foo" 40

41 Construction: String Escaping "This is a line and this is a new line" "This is a "quote"" 41

42 Construction: Numbers E23 42

43 Construction: Booleans true() false() 43

44 Construction: Other Simple Types date(" ") datetime(" t05:00:00z") long(" ") 44

45 Construction: XML <foo attr="value"> Text <bar/> <!-- comment --> <?target pi?> </foo> 45

46 XQuery: Basic Operations 46

47 Basic Operations: Sequences concatenation 1, true(), "foo", <bar/> 47

48 Basic Operations: Sequences concatenation 1, true(), "foo", <bar/> range 1 to

49 Basic Operations: Arithmetics addition

50 Basic Operations: Arithmetics addition Two steps before the arithmetic computation is made: 50

51 Basic Operations: Arithmetics addition Two steps before the arithmetic computation is made: 1. Atomization 51

52 Basic Operations: Arithmetics addition Two steps before the arithmetic computation is made: 1. Atomization 2. Cast 52

53 Basic Operations: Arithmetics addition Two steps before the arithmetic computation is made: 1. Atomization 2. Cast double("1.42") 53

54 Basic Operations: Arithmetics addition substraction multiplication <a>6</a> * 7 division 42.3 div 7.2 integer division 42 idiv 9 module 42 mod 9 54

55 Basic Operations: Strings concatenation "foo" "bar" concat("foo", "bar") string-join( ("foo", "bar", "foobar"), "-" ) sub-string substr("foobar", 4, 3) length string-length("foobar") 55

56 Basic Operations: Value Comparison equality eq 2 inequality 6 * 7 ne 21 * 2 greater than 234 gt ge 123 less than 42.3 lt le

57 Basic Operations: Value Comparison 1. Zero or one item for each operand 1 eq 2 1 eq () () eq "foo" 57

58 Basic Operations: Value Comparison 1. Zero or one item for each operand (1, 2) eq 2 58

59 Basic Operations: Value Comparison 1. Zero or one item for each operand (1, 2) eq 2 error! 59

60 Basic Operations: Value Comparison 1. Zero or one item for each operand (1, 2) eq 2 error! 2. Types must be compatible 60

61 Basic Operations: Value Comparison 1. Zero or one item for each operand (1, 2) eq 2 error! 2. Types must be compatible 1 eq "foo" 61

62 Basic Operations: Value Comparison 1. Zero or one item for each operand (1, 2) eq 2 error! 2. Types must be compatible 1 eq "foo" error! 62

63 Basic Operations: General Comparison $doc//country/name = "Switzerland" 63

64 Basic Operations: General Comparison $doc//country/name = "Switzerland" =!= < > <= <= 64

65 Basic Operations: General Comparison $doc//country/name = "Switzerland" At least one =!= < > <= <= 65

66 Basic Operations: Logics conjunction 1+1 eq 2 and 2+2 eq 4 disjunction 1+1 eq 2 or 2+2 eq 4 not not(100 mod 5 eq 0) 66

67 Basic Operations: Logics conjunction 1+1 eq 2 and 2+2 eq 4 disjunction 1+1 eq 2 or 2+2 eq 4 not not(100 mod 5 eq 0) universal quantifier existential quantifier every $i in (1 to 10) satisfies $i gt 0 some $i in (1 to 10) satisfies $i eq 3*3 67

68 Basic Operations: Logics 1. It's two-valued logics 68

69 Basic Operations: Logics 1. It's two-valued logics 2. Non-booleans get converted not("foo") 69

70 Basic Operations: Effective Boolean Value Sequence "" Effective Boolean Value (EBV) 70

71 Basic Operations: Effective Boolean Value Sequence "" false Effective Boolean Value (EBV) 71

72 Basic Operations: Effective Boolean Value Sequence "" false "foo" Effective Boolean Value (EBV) 72

73 Basic Operations: Effective Boolean Value Sequence "" false Effective Boolean Value (EBV) "foo" true 73

74 Basic Operations: Effective Boolean Value Sequence "" false Effective Boolean Value (EBV) "foo" 0 true 74

75 Basic Operations: Effective Boolean Value Sequence "" false "foo" Effective Boolean Value (EBV) true 0 false 75

76 Basic Operations: Effective Boolean Value Sequence "" false "foo" Effective Boolean Value (EBV) true 0 false 42 76

77 Basic Operations: Effective Boolean Value Sequence "" false "foo" Effective Boolean Value (EBV) true 0 false 42 true 77

78 Basic Operations: Effective Boolean Value Sequence "" false "foo" Effective Boolean Value (EBV) true 0 false 42 true (<foo/>, <bar/>, 1, "foo") 78

79 Basic Operations: Effective Boolean Value Sequence "" false "foo" Effective Boolean Value (EBV) true 0 false 42 true (<foo/>, <bar/>, 1, "foo") true 79

80 Basic Operations: Effective Boolean Value Sequence "" false "foo" Effective Boolean Value (EBV) true 0 false 42 true (<foo/>, <bar/>, 1, "foo") () true 80

81 Basic Operations: Effective Boolean Value Sequence "" false "foo" Effective Boolean Value (EBV) true 0 false 42 true (<foo/>, <bar/>, 1, "foo") true () false 81

82 Composability 82

83 Rule of Thumb Any Expression can be the operand of any other expression. 83

84 Precedence Precedence (low first) Comma 84

85 Precedence Precedence (low first) Comma Data Flow (FLWOR, if-then-else, switch...) 85

86 Precedence Precedence (low first) Comma Data Flow (FLWOR, if-then-else, switch...) Logic 86

87 Precedence Precedence (low first) Comma Data Flow (FLWOR, if-then-else, switch...) Logic Comparison 87

88 Precedence Precedence (low first) Comma Data Flow (FLWOR, if-then-else, switch...) Logic Comparison String concatenation 88

89 Precedence Precedence (low first) Comma Data Flow (FLWOR, if-then-else, switch...) Logic Comparison String concatenation Range 89

90 Precedence Precedence (low first) Comma Data Flow (FLWOR, if-then-else, switch...) Logic Comparison String concatenation Range Arithmetic 90

91 Precedence Precedence (low first) Comma Data Flow (FLWOR, if-then-else, switch...) Logic Comparison String concatenation Range Arithmetic Path expressions 91

92 Precedence Precedence (low first) Comma Data Flow (FLWOR, if-then-else, switch...) Logic Comparison String concatenation Range Arithmetic Path expressions Filter predicates, dynamic function calls 92

93 Precedence Precedence (low first) Comma Data Flow (FLWOR, if-then-else, switch...) Logic Comparison String concatenation Range Arithmetic Path expressions Filter predicates, dynamic function calls Literals, constructors and variables Function calls, named function references, inline functions 93

94 Precedence Precedence (low first) Comma Data Flow (FLWOR, if-then-else, switch...) Logic Comparison String concatenation Range Arithmetic Path expressions Filter predicates, dynamic function calls Literals, constructors and variables Function calls, named function references, inline functions Use parentheses to override or when in doubt! 94

95 XML Construction reloaded <foo attr="{string-length("foobar")}"> { string-join( for $i in 1 to 10 return string($i), "-" ) } </foo> 95

96 XML Construction reloaded <foo attr="{string-length("foobar")}"> { string-join( for $i in 1 to 10 return string($i), "-" ) } </foo> <foo attr="6"> </foo> 96

97 Data Flow (XQuery) 97

98 Conditional Expressions if(count(doc("file.xml")//country) gt 1000) then "Large file!" else "Small file." 98

99 Switch Expressions switch($country/code) case "CH" return ("gsw", "de", "fr", "it", "rm") case "F" return "fr" case "D" return "de" case "I" return "it" default return "en" 99

100 Try Catch Expressions try { xs:integer($country/code) } catch * { "A country code is not an integer!" } 100

101 Alexander Raths / 123RF Stock Photo FLWOR Expressions (XQuery) 101

102 Let clauses let $x := 2 return $x * $x 102

103 Let clauses let $x := 2 let $y := $x + $x let $x := $y + 3 return $x * $x 103

104 For clauses for $x in (1, 2, 4) return $x * $x 104

105 Where clauses for $x in 1 to 10 where $x - 2 gt 5 return $x * $x 105

106 For clauses for $x in 1 to 10 return <square number="{$x}">{ $x * $x }</square> 106

107 Order by clauses for $x in doc("countries.xml")//country order by $x/population return $x/name/data() 107

108 Group by clauses for $x in doc("countries.xml")//country group by $continent := return <continent code="{$continent}">{ for $country in $x return $country/name }</continent> 108

109 Tuple stream semantics for $x in 1 to 10 where $x - 2 gt 5 return $x * $x 109

110 Tuple stream semantics for $x in 1 to 10 x 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 x 10 where $x - 2 gt 5 return $x * $x 110

111 Tuple stream semantics for $x in 1 to 10 x 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 x 10 where $x - 2 gt 5 x 8 x 9 x 10 return $x * $x 111

112 Tuple stream semantics for $x in 1 to 10 x 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 x 10 where $x - 2 gt 5 x 8 x 9 x 10 return $x * $x (64, 81, 100) 112

113 Tuple stream semantics for $x in 1 to 5 let $y := $x - 2 return $x * $y 113

114 Tuple stream semantics for $x in 1 to 5 x 1 x 2 x 3 x 4 x 5 let $y := $x - 2 return $x * $y 114

115 Tuple stream semantics for $x in 1 to 5 x 1 x 2 x 3 x 4 x 5 let $y := $x - 2 x 1 y -1 x 2 y 0 x 3 y 1 x 4 y 2 x 5 y 3 return $x * $y 115

116 Tuple stream semantics for $x in 1 to 5 x 1 x 2 x 3 x 4 x 5 let $y := $x - 2 x 1 y -1 x 2 y 0 x 3 y 1 x 4 y 2 x 5 y 3 return $x * $y (-1, 0, 3, 8, 15) 116

117 Tuple stream semantics for $x in 1 to 5 group by $y := $x mod 2 return { "foo" : $y, "bar" : count($x) } 117

118 Tuple stream semantics for $x in 1 to 5 x 1 x 2 x 3 x 4 x 5 group by $y := $x mod 2 return { "foo" : $y, "bar" : count($x) } 118

119 Tuple stream semantics for $x in 1 to 5 x 1 x 2 x 3 x 4 x 5 group by $y := $x mod 2 y 0 y 1 return { "foo" : $y, "bar" : count($x) } 119

120 Tuple stream semantics for $x in 1 to 5 x 1 x 2 x 3 x 4 x 5 group by $y := $x mod 2 y 0 x 2 4 y 1 x return { "foo" : $y, "bar" : count($x) } 120

121 Tuple stream semantics for $x in 1 to 5 x 1 x 2 x 3 x 4 x 5 group by $y := $x mod 2 y 0 x 2 4 y 1 x return { "foo" : $y, "bar" : count($x) } { "foo" : 0, "bar" : 2 }, { "foo" : 1, "bar" : 3 } 121

122 Types 122

123 Types Simple types: by name xs:integer 123

124 Types Simple types: by name xs:integer Complex types: by kind, similar to XPath element(foo) 124

125 Cardinality xs:integer 125

126 Cardinality xs:integer xs:boolean? 126

127 Cardinality xs:integer xs:boolean? element(foo)+ 127

128 Cardinality xs:integer xs:boolean? element(foo)+ document-node()* 128

129 Type usage let $x as xs:integer := 2 return $x + $x 129

130 Type usage let $x as node() := <foo>2</foo> return $x + $x 130

131 Type usage for $x as element(foo)* in ( <foo>2</foo>, <foo>3</foo> ) return $x + $x 131

132 Type usage for $x as element(foo)* in ( <foo>2</foo>, <foo>3</foo> ) return $x + $x treat as xs:integer 132

133 Type usage for $x as element(foo)* in ( <foo>2</foo>, <foo>3</foo> ) return $x + $x cast as xs:double 133

134 Type usage for $x as element(foo)* in ( <foo>2</foo>, <foo>3</foo> ) return xs:double($x + $x) 134

135 Type usage 3.14 instance of xs:integer 135

136 Type usage 3.14 castable as xs:double 136

137 Type usage declare function local:is-big-data( $threshold as xs:integer, $doc as document-node() ) as xs:boolean { count($doc//*) gt $threshold }; 137

138 Type usage declare function local:is-big-data( $threshold as xs:integer, $doc as document-node() ) as xs:boolean { count($doc//*) gt $threshold }; local:is-big-data(1000, doc("big-file.xml") 138

139 Validation import'schema'namespace'm!=! validate!{! <m:math!xmlns:m=" </m:math>! }!! 139

140 Querying JSON (XQuery 3.1 / JSONiq) 140

141 JSON Navigation: Objects let $object := { "foo": 31, "bar" : "ETH" } return $object.foo JSONiq 141

142 JSON Navigation: Objects let $object := { "foo": 31, "bar" : "ETH" } return $object.foo let $object := map { "foo": 31, "bar" : "ETH" } return $object?foo JSONiq XQuery

143 JSON Navigation: Arrays let $object := { "foo": 31, "bar": [ "ETH", "EPF" ] } return $object.foo[[1]] JSONiq 143

144 JSON Navigation: Arrays let $object := { "foo": 31, "bar": [ "ETH", "EPF" ] } return $object.foo[[1]] let $object := map { "foo": 31, "bar": array { "ETH", "EPF" } } return $object?foo?1 JSONiq XQuery

145 JSON Navigation: Arrays let $object := { "foo": 31, "bar": [ "ETH", "EPF" ] } return $object.foo[] JSONiq 145

146 JSON Navigation: Arrays let $object := { "foo": 31, "bar": [ "ETH", "EPF" ] } return $object.foo[] let $object := map { "foo": 31, "bar": array { "ETH", "EPF" } } return $object?foo?* JSONiq XQuery

147 JSON Construction: Composability map { "Swiss people" : doc("switzerland.xml") //country/population/data() } 147

148 JSON Construction: XQuery 3.1 and arrays array { 1 to 3, (), 4 to 6 } 148

149 JSON Construction: XQuery 3.1 and arrays array { 1 to 3, (), 4 to 6 } [ 1, 2, 3, 4, 5, 6 ] 149

150 JSON Construction: XQuery 3.1 and arrays array { 1 to 3, (), 4 to 6 } [ 1, 2, 3, 4, 5, 6 ] [ 1 to 3, (), 4 to 6 ] 150

151 JSON Construction: XQuery 3.1 and arrays array { 1 to 3, (), 4 to 6 } [ 1, 2, 3, 4, 5, 6 ] [ 1 to 3, (), 4 to 6 ] [ (1, 2, 3), (), (4, 5, 6) ] 151

152 XQuery 3.1 vs. JSONiq XQuery 3.1 JSONiq Primary use case data structures (maps, arrays) document stores (JSON) 152

153 XQuery 3.1 vs. JSONiq XQuery 3.1 JSONiq Primary use case data structures (maps, arrays) document stores (JSON) Keys Any atomic types Strings only 153

154 XQuery 3.1 vs. JSONiq XQuery 3.1 JSONiq Primary use case data structures (maps, arrays) document stores (JSON) Keys Any atomic types Strings only Values Any sequences of items Single items 154

155 XQuery 3.1 vs. JSONiq XQuery 3.1 JSONiq Primary use case data structures (maps, arrays) document stores (JSON) Keys Any atomic types Strings only Values Any sequences of items Single items Constructor content Preserving identity Copied 155

156 Final examples 156

157 Example 157

158 Titles sorted by price for$$b!in$doc("bib.xml")//book! order$by$xs:float($b/price)!descending,!!!!!!!!!!$b/title!ascending! return$$b/title!! 158

159 Titles sorted by price for$$b!in$doc("bib.xml")//book!!!! 159

160 Titles sorted by price for$$b!in$doc("bib.xml")//book! order$by$xs:float($b/price)!descending,!!!!!!!!!!$b/title!ascending!!! 160

161 Titles sorted by price for$$b!in$doc("bib.xml")//book! order$by$xs:float($b/price)!descending,!!!!!!!!!!$b/title!ascending! return$$b/title!! 161

162 How many books written by Stevens? doc("bib.xml")//book+ 162

163 How many books written by Stevens? doc("bib.xml")//book[author,=,"stevens"], 163

164 How many books written by Abiteboul? 2 count(doc("bib.xml")//book[author,=,"stevens"]), 164

165 Number of books by author doc("bib.xml")** 165

166 Number of books by author doc("bib.xml")//author

167 Number of books by author for$$a!in$doc("bib.xml")//author/data()! 167

168 Number of books by author for$$a!in$distinct' values(doc("bib.xml")//author)!!!!! 168

169 Number of books by author <?xml version="1.0" encoding="utf-8"?> <res> <name>stevens</name> </res> <res> <name>abiteboul</name> </res> <res> <name>buneman</name> </res> <res> <name>suciu</name> </res> for$$a!in$distinct' values(doc("bib.xml")//author)! return$<res>!!!<name>{$a}</name>!!!<count>!!!{!!!!!count(doc("bib.xml")//book[author!=!$a])!!!}!!!</count>! </res>!!!! 169

170 Number of books by author <?xml version="1.0" encoding="utf-8"?> <res> <name>stevens</name> <count>2</count> </res> <res> <name>abiteboul</name> <count>2</count> </res> <res> <name>buneman</name> <count>1</count> </res> <res> <name>suciu</name> <count>1</count> </res> for$$a!in$distinct' values(doc("bib.xml")//author)! return$<res>!!!<name>{$a}</name>!!!<count>!!!{!!!!!count(doc("bib.xml")//book[author!=!$a])!!!}!!!</count>! </res>!!!! 170

171 Not covered Higher-order functions Computed constructors Count clause Window clause Node comparison Errors Typeswitch 171

172 There s more XQuery Updates XQuery Full-Text XQuery Scripting insert node <foo/> into $doc/bar /books/book[@number="1"]/title contains text "improve" using stemming while ($x gt 0) { $x := $x 1; } 172