doc/man1/htsn-import.1

   1 .TH htsn-import 1
   2
   3 .SH NAME
   4 htsn-import \- Import XML files from The Sports Network into an RDBMS.
   5
   6 .SH SYNOPSIS
   7
   8 \fBhtsn-import\fR [OPTIONS] [FILES]
   9
  10 .SH DESCRIPTION
  11 .P
  12 The Sports Network <http://www.sportsnetwork.com/> offers an XML feed
  13 containing various sports news and statistics. Our sister program
  14 \fBhtsn\fR is capable of retrieving the feed and saving the individual
  15 XML documents contained therein. But what to do with them?
  16 .P
  17 The purpose of \fBhtsn-import\fR is to take these XML documents and
  18 get them into something we can use, a relational database management
  19 system (RDBMS), otherwise known as a SQL database. The structure of
  20 relational database, is, well, relational, and the feed XML is not. So
  21 there is some work to do before the data can be imported into the
  22 database.
  23 .P
  24 First, we must parse the XML. Each supported document type (see below)
  25 has a full pickle/unpickle implementation (\(dqpickle\(dq is simply a
  26 synonym for serialize here). That means that we parse the entire
  27 document into a data structure, and if we pickle (serialize) that data
  28 structure, we get the exact same XML document tha we started with.
  29 .P
  30 This is important for two reasons. First, it serves as a second level
  31 of validation. The first validation is performed by the XML parser,
  32 but if that succeeds and unpicking fails, we know that something is
  33 fishy. Second, we don't ever want to be surprised by some new element
  34 or attribute showing up in the XML. The fact that we can unpickle the
  35 whole thing now means that we won't be surprised in the future.
  36 .P
  37 The aforementioned feature is especially important because we
  38 automatically migrate the database schema every time we import a
  39 document. If you attempt to import a \(dqnewsxml.dtd\(dq document, all
  40 database objects relating to the news will be created if they do not
  41 exist. We don't want the schema to change out from under us without
  42 warning, so it's important that no XML be parsed that would result in
  43 a different schema than we had previously. Since we can
  44 pickle/unpickle everything already, this should be impossible.
  45
  46 .SH SUPPORTED DOCUMENT TYPES
  47 .P
  48 The XML document types obtained from the feed are uniquely identified
  49 by their DTDs. We currently support documents with the following DTDs:
  50 .IP \[bu] 2
  51 AutoRacingResultsXML.dtd
  52 .IP \[bu]
  53 Auto_Racing_Schedule_XML.dtd
  54 .IP \[bu]
  55 Heartbeat.dtd
  56 .IP \[bu]
  57 Injuries_Detail_XML.dtd
  58 .IP \[bu]
  59 injuriesxml.dtd
  60 .IP \[bu]
  61 newsxml.dtd
  62 .IP \[bu]
  63 Odds_XML.dtd
  64 .IP \[bu]
  65 scoresxml.dtd
  66 .IP \[bu]
  67 weatherxml.dtd
  68 .IP \[bu]
  69 GameInfo
  70 .RS
  71 .IP \[bu]
  72 CBASK_Lineup_XML.dtd
  73 .IP \[bu]
  74 cbaskpreviewxml.dtd
  75 .IP \[bu]
  76 cflpreviewxml.dtd
  77 .IP \[bu]
  78 Matchup_NBA_NHL_XML.dtd
  79 .IP \[bu]
  80 MLB_Gaming_Matchup_XML.dtd
  81 .IP \[bu]
  82 MLB_Lineup_XML.dtd
  83 .IP \[bu]
  84 MLB_Matchup_XML.dtd
  85 .IP \[bu]
  86 MLS_Preview_XML.dtd
  87 .IP \[bu]
  88 mlbpreviewxml.dtd
  89 .IP \[bu]
  90 NBA_Gaming_Matchup_XML.dtd
  91 .IP \[bu]
  92 NBA_Playoff_Matchup_XML.dtd
  93 .IP \[bu]
  94 NBALineupXML.dtd
  95 .IP \[bu]
  96 nbapreviewxml.dtd
  97 .IP \[bu]
  98 NCAA_FB_Preview_XML.dtd
  99 .IP \[bu]
 100 NFL_NCAA_FB_Matchup_XML.dtd
 101 .IP \[bu]
 102 nflpreviewxml.dtd
 103 .IP \[bu]
 104 nhlpreviewxml.dtd
 105 .IP \[bu]
 106 recapxml.dtd
 107 .IP \[bu]
 108 WorldBaseballPreviewXML.dtd
 109 .RE
 110 .IP \[bu]
 111 SportInfo
 112 .RS
 113 .IP \[bu]
 114 CBASK_3PPctXML.dtd
 115 .IP \[bu]
 116 Cbask_All_Tourn_Teams_XML.dtd
 117 .IP \[bu]
 118 CBASK_AssistsXML.dtd
 119 .IP \[bu]
 120 Cbask_Awards_XML.dtd
 121 .IP \[bu]
 122 CBASK_BlocksXML.dtd
 123 .IP \[bu]
 124 Cbask_Conf_Standings_XML.dtd
 125 .IP \[bu]
 126 Cbask_DivII_III_Indv_Stats_XML.dtd
 127 .IP \[bu]
 128 Cbask_DivII_Team_Stats_XML.dtd
 129 .IP \[bu]
 130 Cbask_DivIII_Team_Stats_XML.dtd
 131 .IP \[bu]
 132 CBASK_FGPctXML.dtd
 133 .IP \[bu]
 134 CBASK_FoulsXML.dtd
 135 .IP \[bu]
 136 CBASK_FTPctXML.dtd
 137 .IP \[bu]
 138 Cbask_Indv_Scoring_XML.dtd
 139 .IP \[bu]
 140 CBASK_MinutesXML.dtd
 141 .IP \[bu]
 142 Cbask_Polls_XML.dtd
 143 .IP \[bu]
 144 CBASK_ReboundsXML.dtd
 145 .IP \[bu]
 146 CBASK_ScoringLeadersXML.dtd
 147 .RE
 148 .P
 149 The GameInfo and SportInfo types do not have their own top-level
 150 tables in the database. Instead, their raw XML is stored in either the
 151 \(dqgame_info\(dq or \(dqsport_info\(dq table respectively.
 152
 153 .SH DATABASE SCHEMA
 154 .P
 155 At the top level (with two notable exceptions), we have one table for
 156 each of the XML document types that we import. For example, the
 157 documents corresponding to \fInewsxml.dtd\fR will have a table called
 158 \(dqnews\(dq. All top-level tables contain two important fields,
 159 \(dqxml_file_id\(dq and \(dqtime_stamp\(dq. The former is unique and
 160 prevents us from inserting the same data twice. The time stamp on the
 161 other hand lets us know when the data is old and can be removed. The
 162 database schema make it possible to delete only the outdated top-level
 163 records; all transient children should be removed by triggers.
 164 .P
 165 These top-level tables will often have children. For example, each
 166 news item has zero or more locations associated with it. The child
 167 table will be named <parent>_<children>, which in this case
 168 corresponds to \(dqnews_locations\(dq.
 169 .P
 170 To relate the two, a third table may exist with name
 171 <parent>__<child>. Note the two underscores. This prevents ambiguity
 172 when the child table itself contains underscores. The table joining
 173 \(dqnews\(dq with \(dqnews_locations\(dq is thus called
 174 \(dqnews__news_locations\(dq. This is necessary when the child table
 175 has a unique constraint; we don't want to blindly insert duplicate
 176 records keyed to the parent. Instead we'd like to use the third table
 177 to map an existing child to the new parent.
 178 .P
 179 Where it makes sense, children are kept unique to prevent pointless
 180 duplication. This slows down inserts, and speeds up reads (which are
 181 much more frequent). There is a tradeoff to be made, however. For a
 182 table with a small, fixed upper bound on the number of rows (like
 183 \(dqodds_casinos\(dq), there is great benefit to de-duplication. The
 184 total number of rows stays small, so inserts are still quick, and many
 185 duplicate rows are eliminated.
 186 .P
 187 But, with a table like \(dqodds_games\(dq, the number of games grows
 188 quickly and without bound. It is therefore more beneficial to be able
 189 to delete the old games (through an ON DELETE CASCADE, tied to
 190 \(dqodds\(dq) than it is to eliminate duplication. A table like
 191 \(dqnews_locations\(dq is somewhere in-between. It is hoped that the
 192 unique constraint in the top-level table's \(dqxml_file_id\(dq will
 193 prevent duplication in this case anyway.
 194 .P
 195 The aforementioned exceptions are the \(dqgame_info\(dq and
 196 \(dqsport_info\(dq tables. These tables contain the raw XML for a
 197 number of DTDs that are not handled individually. This is partially
 198 for backwards-compatibility with a legacy implementation, but is
 199 mostly a stopgap due to a lack of resources at the moment. These two
 200 tables (game_info and sport_info) still possess timestamps that allow
 201 us to prune old data.
 202 .P
 203 UML diagrams of the resulting database schema for each XML document
 204 type are provided with the \fBhtsn-import\fR documentation.
 205
 206 .SH XML Schema Oddities
 207 .P
 208 There are a number of problems with the XML on the wire. Even if we
 209 construct the DTDs ourselves, the results are sometimes
 210 inconsistent. Here we document a few of them.
 211
 212 .IP \[bu] 2
 213 Odds_XML.dtd
 214
 215 The <Notes> elements here are supposed to be associated with a set of
 216 <Game> elements, but since the pair
 217 (<Notes>...</Notes><Game>...</Game>) can appear zero or more times,
 218 this leads to ambiguity in parsing. We therefore ignore the notes
 219 entirely (although a hack is employed to facilitate parsing).
 220
 221 .IP \[bu]
 222 weatherxml.dtd
 223
 224 There appear to be two types of weather documents; the first has
 225 <listing> contained within <forecast> and the second has <forecast>
 226 contained within <listing>. While it would be possible to parse both,
 227 it would greatly complicate things. The first form is more common, so
 228 that's all we support for now.
 229
 230 .SH OPTIONS
 231
 232 .IP \fB\-\-backend\fR,\ \fB\-b\fR
 233 The RDBMS backend to use. Valid choices are \fISqlite\fR and
 234 \fIPostgres\fR. Capitalization is important, sorry.
 235
 236 Default: Sqlite
 237
 238 .IP \fB\-\-connection-string\fR,\ \fB\-c\fR
 239 The connection string used for connecting to the database backend
 240 given by the \fB\-\-backend\fR option. The default is appropriate for
 241 the \fISqlite\fR backend.
 242
 243 Default: \(dq:memory:\(dq
 244
 245 .IP \fB\-\-log-file\fR
 246 If you specify a file here, logs will be written to it (possibly in
 247 addition to syslog). Can be either a relative or absolute path. It
 248 will not be auto-rotated; use something like logrotate for that.
 249
 250 Default: none
 251
 252 .IP \fB\-\-log-level\fR
 253 How verbose should the logs be? We log notifications at four levels:
 254 DEBUG, INFO, WARN, and ERROR. Specify the \(dqmost boring\(dq level of
 255 notifications you would like to receive (in all-caps); more
 256 interesting notifications will be logged as well. The debug output is
 257 extremely verbose and will not be written to syslog even if you try.
 258
 259 Default: INFO
 260
 261 .IP \fB\-\-remove\fR,\ \fB\-r\fR
 262 Remove successfully processed files. If you enable this, you can see
 263 at a glance which XML files are not being processed, because they're
 264 all that should be left.
 265
 266 Default: disabled
 267
 268 .IP \fB\-\-syslog\fR,\ \fB\-s\fR
 269 Enable logging to syslog. On Windows this will attempt to communicate
 270 (over UDP) with a syslog daemon on localhost, which will most likely
 271 not work.
 272
 273 Default: disabled
 274
 275 .SH CONFIGURATION FILE
 276 .P
 277 Any of the command-line options mentioned above can be specified in a
 278 configuration file instead. We first look for \(dqhtsn-importrc\(dq in
 279 the system configuration directory. We then look for a file named
 280 \(dq.htsn-importrc\(dq in the user's home directory. The latter will
 281 override the former.
 282 .P
 283 The user's home directory is simply $HOME on Unix; on Windows it's
 284 wherever %APPDATA% points. The system configuration directory is
 285 determined by Cabal; the \(dqsysconfdir\(dq parameter during the
 286 \(dqconfigure\(dq step is used.
 287 .P
 288 The file's syntax is given by examples in the htsn-importrc.example file
 289 (included with \fBhtsn-import\fR).
 290 .P
 291 Options specified on the command-line override those in either
 292 configuration file.
 293
 294 .SH EXAMPLES
 295 .IP \[bu] 2
 296 Import newsxml.xml into a preexisting sqlite database named \(dqfoo.sqlite3\(dq:
 297
 298 .nf
 299 .I $ htsn-import --connection-string='foo.sqlite3' \\\\
 300 .I "              test/xml/newsxml.xml"
 301 Successfully imported test/xml/newsxml.xml.
 302 Imported 1 document(s) total.
 303 .fi
 304 .IP \[bu]
 305 Repeat the previous example, but delete newsxml.xml afterwards:
 306
 307 .nf
 308 .I $ htsn-import --connection-string='foo.sqlite3' \\\\
 309 .I "              --remove test/xml/newsxml.xml"
 310 Successfully imported test/xml/newsxml.xml.
 311 Imported 1 document(s) total.
 312 Removed processed file test/xml/newsxml.xml.
 313 .fi
 314 .IP \[bu]
 315 Use a Postgres database instead of the default Sqlite. This assumes
 316 that you have a database named \(dqhtsn\(dq accessible to user
 317 \(dqpostgres\(dq locally:
 318
 319 .nf
 320 .I $ htsn-import --connection-string='dbname=htsn user=postgres' \\\\
 321 .I "              --backend=Postgres test/xml/newsxml.xml"
 322 Successfully imported test/xml/newsxml.xml.
 323 Imported 1 document(s) total.
 324 .fi
 325
 326 .SH BUGS
 327
 328 .P
 329 Send bugs to michael@orlitzky.com.