/docs/user/metacatquery.html - Annotate - Metacat - Ecoinformatics Redmine

878

berkley

<!--

2

  * metacatquery.html

3

4

  *      Authors: Jivka Bojilova

5

  *    Copyright: 2000 Regents of the University of California and the

6

  *               National Center for Ecological Analysis and Synthesis

7

  *  For Details: http://www.nceas.ucsb.edu/

8

  *      Created: 2000 April 5

9

  *      Version: 0.01

10

  *    File Info: '$Id$'

11

12

  * October Meeting SDSC, 2000

13

-->

14

<HTML>

15

<HEAD>

16

<TITLE>Metacat</TITLE>

17

<link rel="stylesheet" type="text/css" href="@docrooturl@default.css">

18

</HEAD>

19

<BODY>

20

  <table width="100%">

21

    <tr>

22

      <td class="tablehead" colspan="2"><p class="label">Queries and Results</p></td>

23

      <td class="tablehead" colspan="2" align="right">

24

        <a href="./metacatload.html">Back</a> | <a href="./metacattour.html">Home</a> |

25

        <a href="./metacatread.html">Next</a>

26

      </td>

27

    </tr>

28

  </table>

29

  <P>The Metacat Server provides

30

  an interface for searching of metadata stored in the Metacat database.

31

  <P> <img alt="architecture diagram of a Metacat query" src="metadataquery.gif">

32

  <br><br><b>Steps to performing a query in Metacat</b>

33

  <ol>

34

    <li>A pathquery document is created from the search criteria provide through

35

    the servlet parameters.</li>

36

    <li>This pathquery document is sent to DBQuery where it

37

    is processed and translated into SQL statements.</li>

38

    <li>The SQL statements are executed against the database and the resultsets

39

    are translated into an xml document of doctype "resultset".</li>

40

    <li>The resultset document is either returned directly to the client as XML

41

    or is transformed through XSLT and returned as HTML.</li>

42

  </ol>

43

44

  <b>The Pathquery Document</b>

45

  <pre>

46

   &lt;pathquery version="1.0"&gt;

47

      &lt;meta_file_id&gt;unspecified&lt;/meta_file_id&gt;

48

      &lt;querytitle&gt;unspecified&lt;/querytitle&gt;

49

      &lt;returnfield&gt;resource/dataset/originator/individualName/surName&lt;/returnfield>

50

      &lt;returnfield&gt;resource/dataset/originator/individualName/givenName&lt;/returnfield>

51

      &lt;returnfield&gt;resource/dataset/keywordInfo/keyword&lt;/returnfield>

52

      &lt;returndoctype&gt;&lt;/returndoctype>

53

      &lt;querygroup operator="UNION"&gt;

54

        &lt;queryterm casesensitive="false" searchmode="contains"&gt;

55

          &lt;value>%&lt;/value&gt;

56

        &lt;/queryterm&gt;

57

        &lt;queryterm casesensitive="false" searchmode="contains"&gt;

58

          &lt;value&gt;-//NCEAS//resource//EN&lt;/value&gt;

59

          &lt;pathexpr&gt;returndoc&lt;/pathexpr&gt;

60

        &lt;/queryterm&gt;

61

        &lt;queryterm casesensitive="false" searchmode="contains"&gt;

62

          &lt;value&gt;-//NCEAS//eml-dataset//EN&lt;/value&gt;

63

          &lt;pathexpr&gt;returndoc&lt;/pathexpr&gt;

64

        &lt;/queryterm&gt;

65

      &lt;/querygroup&gt;

66

    &lt;/pathquery&gt;

67

  </pre>

68

69

  <p>The pathquery document was designed to be flexible enough to query specific

70

  fields of any XML document.  It also allows the client to specify which fields

71

  from a returned document are returned in the initial resultset.  Each

72

  &lt;returnfield&gt; parameter specifies a field which the DB will return

73

  for any query hit.  The returndoctype fields allows the client to limit the

74

  type of documents to be returned.  If left blank, all document types are returned.

75

  A &lt;querygroup&gt; creates an AND or an OR statement of the &lt;queryterm&gt;s

76

  in the group.  The operator can be UNION or INTERSECTION.  A &lt;queryterm&gt;

77

  defines the actual field against which the query is being performed.  The value

78

  of the queryterm that we are quering for is encased in &lt;value&gt; tags.

79

  The &lt;pathexpr&gt; tag specifies an exact path to which you want to restrict

80

  the search.  A &lt;pathexpr&gt; tag which contains the keyword returndoc is

81

  a special case which is discussed in <a href="./packages.html">Packages and

82

  Relations</a>.</p><br>

83

84

  <b>The Resultset Document</b><br>

85

86

  <p>When the pathquery document is submitted and processed, Metacat returns

87

  another XML document called a resultset document.<p>

88

89

  <pre>

90

        &lt;resultset&gt;

91

        &lt;query&gt;

92

          &lt;pathquery version="1.0"&gt;

93

            &lt;meta_file_id&gt;unspecified&lt;/meta_file_id&gt;

94

            &lt;querytitle&gt;unspecified&lt;/querytitle&gt;

95

            &lt;returnfield&gt;resource/dataset/originator/individualName/surName&lt;/returnfield&gt;

96

            &lt;returnfield&gt;resource/dataset/originator/individualName/givenName&lt;/returnfield&gt;

97

            &lt;returnfield&gt;resource/dataset/keywordInfo/keyword&lt;/returnfield&gt;

98

            &lt;returndoctype&gt;&lt;/returndoctype&gt;

99

            &lt;querygroup operator="UNION"&gt;

100

              &lt;queryterm casesensitive="false" searchmode="contains"&gt;

101

                &lt;value&gt;%&lt;/value&gt;

102

              &lt;/queryterm&gt;

103

              &lt;queryterm casesensitive="false" searchmode="contains"&gt;

104

                &lt;value&gt;-//NCEAS//resource//EN&lt;/value&gt;

105

                &lt;pathexpr&gt;returndoc&lt;/pathexpr&gt;

106

              &lt;/queryterm&gt;

107

              &lt;queryterm casesensitive="false" searchmode="contains"&gt;

108

                &lt;value&gt;-//NCEAS//eml-dataset//EN&lt;/value&gt;

109

                &lt;pathexpr&gt;returndoc&lt;/pathexpr&gt;

110

              &lt;/queryterm&gt;

111

            &lt;/querygroup&gt;

112

          &lt;/pathquery&gt;

113

        &lt;/query&gt;

114

115

        &lt;document&gt;

116

          &lt;docid&gt;nceas.44.1&lt;/docid&gt;

117

          &lt;docname&gt;resource&lt;/docname&gt;

118

          &lt;doctype&gt;-//NCEAS//resource//EN&lt;/doctype&gt;

119

          &lt;doctitle&gt;Surgras1.txt&lt;/doctitle&gt;

120

          &lt;createdate&gt;2001-01-12 16:12:06.0&lt;/createdate&gt;

121

          &lt;updatedate&gt;2001-01-12 16:12:06.0&lt;/updatedate&gt;

122

          &lt;param name="resource/dataset/keywordInfo/keyword"&gt;surfgrass&lt;/param&gt;

123

          &lt;param name="resource/dataset/keywordInfo/keyword"&gt;intertidal&lt;/param&gt;

124

          &lt;param name="resource/dataset/keywordInfo/keyword"&gt;Ventura&lt;/param&gt;

125

          &lt;param name="resource/dataset/keywordInfo/keyword"&gt;Los Angeles&lt;/param&gt;

126

          &lt;relation&gt;

127

            &lt;relationtype&gt;hasTransitiveRelationTo&lt;/relationtype&gt;

128

            &lt;relationdoc&gt;Metacat://dev.nceas.ucsb.edu:8090/Metacat?docid=nceas.43&lt;/relationdoc&gt;

129

            &lt;relationdoctype&gt;-//NCEAS//eml-file//EN&lt;/relationdoctype&gt;

130

          &lt;/relation&gt;

131

          &lt;relation&gt;

132

            &lt;relationtype&gt;isresourcemetadatafor&lt;/relationtype&gt;

133

            &lt;relationdoc&gt;http://www.nceas.ucsb.edu/marine/data/ambrose/surgras1.txt&lt;/relationdoc&gt;

134

            &lt;relationdoctype&gt;null&lt;/relationdoctype&gt;

135

          &lt;/relation&gt;

136

        &lt;/document&gt;

137

138

        &lt;document&gt;

139

          &lt;docid&gt;nceas.42.1&lt;/docid&gt;

140

          &lt;docname&gt;resource&lt;/docname&gt;

141

          &lt;doctype&gt;-//NCEAS//resource//EN&lt;/doctype&gt;

142

          &lt;doctitle&gt;SLottia.txt&lt;/doctitle&gt;

143

          &lt;createdate&gt;2001-01-12 16:11:31.0&lt;/createdate&gt;

144

          &lt;updatedate&gt;2001-01-12 16:11:31.0&lt;/updatedate&gt;

145

          &lt;param name="resource/dataset/keywordInfo/keyword"&gt;lottia&lt;/param&gt;

146

          &lt;param name="resource/dataset/keywordInfo/keyword"&gt;intertidal&lt;/param&gt;

147

          &lt;param name="resource/dataset/keywordInfo/keyword"&gt;Orange&lt;/param&gt;

148

          &lt;relation&gt;

149

            &lt;relationtype&gt;hasTransitiveRelationTo&lt;/relationtype&gt;

150

            &lt;relationdoc&gt;Metacat://dev.nceas.ucsb.edu:8090/Metacat?docid=nceas.41&lt;/relationdoc&gt;

151

            &lt;relationdoctype&gt;-//NCEAS//eml-file//EN&lt;/relationdoctype&gt;

152

          &lt;/relation&gt;

153

          &lt;relation&gt;

154

            &lt;relationtype&gt;isresourcemetadatafor&lt;/relationtype&gt;

155

            &lt;relationdoc&gt;http://www.nceas.ucsb.edu/marine/data/murray/SLottia.txt&lt;/relationdoc&gt;

156

            &lt;relationdoctype&gt;null&lt;/relationdoctype&gt;

157

          &lt;/relation&gt;

158

        &lt;/document&gt;

159

      .....

160

      &lt;/resultset&gt;

161

162

  </pre>

163

  <p>The first element in the resultset is &lt;query&gt;.  As you may notice,

164

  its content is just the pathquery document.  The resultset always returns

165

  the pathquery document that created it in the &lt;query&gt; tag.  The next

166

  major tag is &lt;document&gt;.  Each XML document returned by the query

167

  is represented by a &lt;document&gt; tag.  The default information returned

168

  about a document are docid, docname, doctype, doctitle, createdate and

169

  updatedate.  The param tags are present if the document found contained

170

  the returnfield chosen in the pathquery document.  The name attribute of the

171

  param tag is the full path to the node specified by the returnfield.  &lt;relation&gt;

172

  tags specify any documents to which the returned document is related.  Relations

173

  and packages are talked about <a href="./packages.html">later</a>.<p>

174

175

  <br>

176

  <a href="./metacatload.html">Back</a> | <a href="./metacattour.html">Home</a> |

177

  <a href="./metacatread.html">Next</a>

178

179

</BODY>

180

</HTML>

Project

General

Profile

Metacat

Project

General

Profile

Metacat

metacat/docs/user/metacatquery.html @ 878