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

878

berkley

<!--

2

  * packages.html

3

4

  *      Authors: Chad Berkley

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: 2001 January 23

9

  *      Version:

10

  *    File Info: '$ '

11

12

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">Packages and Relationships</p></td>

23

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

24

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

25

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

26

      </td>

27

    </tr>

28

  </table>

29

  <p>Metacat allows a user to create a virtual link between XML documents within

30

  the system.  These links are called <i>Relationships</i> and are defined by triples

32

878

berkley

  XML or <a href="./datafiles.html">non-XML</a> files.

33

  The following is an example of an eml-dataset-2.0 file holding triples at the end:</p>

34

35

  <pre>

36

&lt;?xml version="1.0"?&gt;

37

&lt;!DOCTYPE dataset PUBLIC "-//NCEAS//eml-dataset-2.0//EN" "eml-dataset-2.0.dtd"&gt;

38

&lt;dataset&gt;

39

  &lt;identifier system="null"&gt;berkley.5.3&lt;/identifier&gt;

40

  &lt;shortName&gt;allsp&lt;/shortName&gt;

41

  &lt;title&gt;MARINE sampling data collected between spring 1992 and fall 1996&lt;/title&gt;

42

  &lt;originator&gt;

43

    &lt;individualName&gt;

44

      &lt;salutation&gt;Dr.&lt;/salutation&gt;

45

      &lt;givenName&gt;Peter&lt;/givenName&gt;

46

      &lt;surName&gt;Raimondi&lt;/surName&gt;

47

    &lt;/individualName&gt;

48

    &lt;organizationName&gt;UCSC&lt;/organizationName&gt;

49

    &lt;positionName&gt; &lt;/positionName&gt;

50

    &lt;address&gt;

51

      &lt;deliveryPoint&gt;Biology Dept.&lt;/deliveryPoint&gt;

52

      &lt;deliveryPoint&gt;A309 Earth and Marine Science Building&lt;/deliveryPoint&gt;

53

      &lt;city&gt;Santa Cruz&lt;/city&gt;

54

      &lt;administrativeArea&gt;CA&lt;/administrativeArea&gt;

55

      &lt;postalCode&gt;95060&lt;/postalCode&gt;

56

      &lt;country&gt;USA&lt;/country&gt;

57

    &lt;/address&gt;

58

    &lt;phone phonetype="voice"&gt;831-459-1234 x5674&lt;/phone&gt;

59

    &lt;electronicMailAddress&gt;raimondi@biology.ucsc.edu&lt;/electronicMailAddress&gt;

60

    &lt;onlineLink&gt; &lt;/onlineLink&gt;

61

    &lt;role&gt;Originator&lt;/role&gt;

62

  &lt;/originator&gt;

63

  &lt;pubdate&gt; &lt;/pubdate&gt;

64

  &lt;pubplace&gt; &lt;/pubplace&gt;

65

  &lt;series&gt; &lt;/series&gt;

66

  &lt;abstract&gt;

67

    &lt;paragraph&gt; &lt;/paragraph&gt;

68

  &lt;/abstract&gt;

69

  &lt;keywordSet&gt;

70

    &lt;keyword keywordType="null"&gt;intertidal&lt;/keyword&gt;

71

    &lt;keyword keywordType="null"&gt;santa barbara&lt;/keyword&gt;

72

    &lt;keyword keywordType="null"&gt;photoplot&lt;/keyword&gt;

73

    &lt;keyword keywordType="null"&gt;quadrat&lt;/keyword&gt;

74

    &lt;keywordThesaurus&gt; &lt;/keywordThesaurus&gt;

75

  &lt;/keywordSet&gt;

76

  &lt;additionalInfo&gt;

77

    &lt;paragraph&gt; &lt;/paragraph&gt;

78

  &lt;/additionalInfo&gt; <font color="red">

79

  &lt;triple&gt;

80

    &lt;subject&gt;berkley.6.1&lt;/subject&gt;

81

    &lt;relationship&gt;isRelatedTo&lt;/relationship&gt;

82

    &lt;object&gt;berkley.5.3&lt;/object&gt;

83

  &lt;/triple&gt;

84

  &lt;triple&gt;

85

    &lt;subject&gt;berkley.7.1&lt;/subject&gt;

86

    &lt;relationship&gt;isRelatedTo&lt;/relationship&gt;

87

    &lt;object&gt;berkley.6.1&lt;/object&gt;

88

  &lt;/triple&gt;

89

  &lt;triple&gt;

90

    &lt;subject&gt;berkley.8.1&lt;/subject&gt;

91

    &lt;relationship&gt;isRelatedTo&lt;/relationship&gt;

92

    &lt;object&gt;berkley.5.3&lt;/object&gt;

93

  &lt;/triple&gt;

94

  &lt;triple&gt;

95

    &lt;subject&gt;berkley.8.1&lt;/subject&gt;

96

    &lt;relationship&gt;isRelatedTo&lt;/relationship&gt;

97

    &lt;object&gt;berkley.6.1&lt;/object&gt;

98

  &lt;/triple&gt;

99

  &lt;triple&gt;

100

    &lt;subject&gt;berkley.8.1&lt;/subject&gt;

101

    &lt;relationship&gt;isRelatedTo&lt;/relationship&gt;

102

    &lt;object&gt;berkley.7.1&lt;/object&gt;

103

  &lt;/triple&gt;

104

  &lt;triple&gt;

105

    &lt;subject&gt;berkley.14.1&lt;/subject&gt;

106

    &lt;relationship&gt;isRelatedTo&lt;/relationship&gt;

107

    &lt;object&gt;berkley.6.1&lt;/object&gt;

108

  &lt;/triple&gt; </font>

109

  &lt;temporalCoverage&gt; 1992 to 1996&lt;/temporalCoverage&gt;

110

  &lt;geographicCoverage&gt; &lt;/geographicCoverage&gt;

111

  &lt;taxonomicCoverage&gt; &lt;/taxonomicCoverage&gt;

112

&lt;/dataset&gt;

113

  </pre>

114

115

  <b>Description of the Package File</b>

116

  <p>Note that the doctype of this document is an unregistered NCEAS specific

117

  DTD (-//NCEAS//eml-dataset-2.0//EN).  The package doctype is an application

118

  property of Metacat.  Setting this property (and others) is described in

119

  <a href="./properties.html">Setting Metacat Properties</a>.  The package file

121

878

berkley

  and an object.  This grouping can be read as follows:  &lt;subject&gt; has

122

  &lt;relationship&gt; to &lt;object&gt;.  Each triple is a logical link

123

  between the subject and object with the relationship being a description of that

124

  link.</p>

125

  <b>The Utility of Relations</b>

126

  <p>Relations become useful because many XML data schemas are broken up into

127

  multiple DTDs.  Thus, there may be many different XML files that are all

128

  related to each other yet are stored seperately within the system.  Also,

129

  since we, here at NCEAS, are developing Metacat for use as a metadata

130

  repository for ecological data, we need some way of linking our metadata

131

  to the datafiles that they describe.  Packages are the way we do this.</p>

132

  <b>Post Processed Relations</b>

133

  <p>The package file is inserted into Metacat as any other file is.  Its doctype

134

  is checked against the packagedoctype property in the <a href="properties.html">

135

  Metacat.properties file</a>.  If it is of that type, the file is sent

136

  to a postprocessor to be analyzed and inserted into the xml_relation table.

137

  The table looks like the following:</p>

138

139

  <table border="1">

140

    <tr>

141

      <td>relationid</td><td>docid</td><td>packagetype</td>

142

      <td>subject</td><td>subjectdoctype</td>

143

      <td>relationship</td><td>object</td><td>objectdoctype</td>

144

    </tr>

145

    <tr>

146

      <td>1</td>

147

      <td>berkley.5</td>

148

      <td>-//NCEAS//eml-dataset-2.0//EN</td>

149

      <td>berkley.6.1</td>

150

      <td>null</td>

151

      <td>isRelatedTo</td>

152

      <td>berkley.5.3</td>

153

      <td>null</td>

154

    </tr>

155

    <tr>

156

      <td>2</td>

157

      <td>berkley.5</td>

158

      <td>-//NCEAS//eml-dataset-2.0//EN</td>

159

      <td>berkley.7.1</td>

160

      <td>null</td>

161

      <td>isRelatedTo</td>

162

      <td>berkley.6.1</td>

163

      <td>null</td>

164

    </tr>

165

    <tr>

166

      <td>3</td>

167

      <td>berkley.5</td>

168

      <td>-//NCEAS//eml-dataset-2.0//EN</td>

169

      <td>berkley.8.1</td>

170

      <td>null</td>

171

      <td>isRelatedTo</td>

172

      <td>berkley.5.3</td>

173

      <td>null</td>

174

    </tr>

175

    <tr>

176

      <td>4</td>

177

      <td>berkley.5</td>

178

      <td>-//NCEAS//eml-dataset-2.0//EN</td>

179

      <td>berkley.8.1</td>

180

      <td>null</td>

181

      <td>isRelatedTo</td>

182

      <td>berkley.6.1</td>

183

      <td>null</td>

184

    </tr>

185

    <tr>

186

      <td>5</td>

187

      <td>berkley.5</td>

188

      <td>-//NCEAS//eml-dataset-2.0//EN</td>

189

      <td>berkley.8.1</td>

190

      <td>null</td>

191

      <td>isRelatedTo</td>

192

      <td>berkley.7.1</td>

193

      <td>null</td>

194

    </tr>

195

    <tr>

196

      <td>6</td>

197

      <td>berkley.5</td>

198

      <td>-//NCEAS//eml-dataset-2.0//EN</td>

199

      <td>berkley.14.1</td>

200

      <td>null</td>

201

      <td>isRelatedTo</td>

202

      <td>berkley.6.1</td>

203

      <td>null</td>

204

    </tr>

205

  </table>

206

207

  <p>Once, the system has processed the package file and inserted the relations

208

  into the xml_relation table, the files relations are always returned to with it

209

  in the <a href="./metacatquery.html">resultset</a> of a query.</p>

210

211

  <b>Package Views (formerly known as 'backtracking')</b>

212

  <p>Package View is a feature that was intentionally left out of the

213

  <a href="./Metacatquery.html">Queries and Results</a> section.  Package views

214

  involves sending a doctype (called a returndoctype) along with a query request.

215

  When there is a hit from that query, the system will check the doctype of the

216

  hit document against the returndoctype.  If the doctypes do not match,

217

  the system checks the xml_relation table to see if that document has been packed

218

  by document of that doctype. If such package document exists, it

219

  is returned instead of the one which was originally hit.  If no such

220

  package document exists, then the document which was originally hit is returned.

221

  This allows a display system (such as a web browser) to try to display a

222

  certain type of document.</p>

223

  <p>For example:  Take our package file from above.  Say we do a query for

224

  "intertidal" which returns the document berkley.6 of type -//NCEAS//eml-entity-2.0//EN.

225

  However, we have set returndoctype equal to "-//NCEAS//eml-dataset-2.0//EN".

226

  When berkley.6 is hit, the system will check its package documents to see if

227

  it is of type -//NCEAS//eml-dataset-2.0//EN.  Since it is,

228

  (relationid 1, 2 and 4) document berkley.5 is returned instead of berkley.6.

229

  <p>From a client the returndoctype is a servlet parameter.

230

  A URL with a returndoctype would look something like: </p>

231

  <pre>http://server.domain.com/Metacat?action=query&amp;anyfield=%&amp;qformat=html&amp;returndoctype=-//NCEAS//eml-dataset-2.0//EN</pre>

232

  <p>The system then inserts the returndoctype parameter value into a pathquery

233

  document as illustrated in <a href="./metacatquery.html">Queries and Results</a>.

234

  </p>

235

236

237

  <br>

238

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

239

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

240

241

242

</BODY>

243

</HTML>

Project

General

Profile

Metacat

Project

General

Profile

Metacat

metacat/docs/user/packages.html @ 2518