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 .RE
 144 .P
 145 The GameInfo and SportInfo types do not have their own top-level
 146 tables in the database. Instead, their raw XML is stored in either the
 147 \(dqgame_info\(dq or \(dqsport_info\(dq table respectively.
 148
 149 .SH DATABASE SCHEMA
 150 .P
 151 At the top level (with two notable exceptions), we have one table for
 152 each of the XML document types that we import. For example, the
 153 documents corresponding to \fInewsxml.dtd\fR will have a table called
 154 \(dqnews\(dq. All top-level tables contain two important fields,
 155 \(dqxml_file_id\(dq and \(dqtime_stamp\(dq. The former is unique and
 156 prevents us from inserting the same data twice. The time stamp on the
 157 other hand lets us know when the data is old and can be removed. The
 158 database schema make it possible to delete only the outdated top-level
 159 records; all transient children should be removed by triggers.
 160 .P
 161 These top-level tables will often have children. For example, each
 162 news item has zero or more locations associated with it. The child
 163 table will be named <parent>_<children>, which in this case
 164 corresponds to \(dqnews_locations\(dq.
 165 .P
 166 To relate the two, a third table may exist with name
 167 <parent>__<child>. Note the two underscores. This prevents ambiguity
 168 when the child table itself contains underscores. The table joining
 169 \(dqnews\(dq with \(dqnews_locations\(dq is thus called
 170 \(dqnews__news_locations\(dq. This is necessary when the child table
 171 has a unique constraint; we don't want to blindly insert duplicate
 172 records keyed to the parent. Instead we'd like to use the third table
 173 to map an existing child to the new parent.
 174 .P
 175 Where it makes sense, children are kept unique to prevent pointless
 176 duplication. This slows down inserts, and speeds up reads (which are
 177 much more frequent). There is a tradeoff to be made, however. For a
 178 table with a small, fixed upper bound on the number of rows (like
 179 \(dqodds_casinos\(dq), there is great benefit to de-duplication. The
 180 total number of rows stays small, so inserts are still quick, and many
 181 duplicate rows are eliminated.
 182 .P
 183 But, with a table like \(dqodds_games\(dq, the number of games grows
 184 quickly and without bound. It is therefore more beneficial to be able
 185 to delete the old games (through an ON DELETE CASCADE, tied to
 186 \(dqodds\(dq) than it is to eliminate duplication. A table like
 187 \(dqnews_locations\(dq is somewhere in-between. It is hoped that the
 188 unique constraint in the top-level table's \(dqxml_file_id\(dq will
 189 prevent duplication in this case anyway.
 190 .P
 191 The aforementioned exceptions are the \(dqgame_info\(dq and
 192 \(dqsport_info\(dq tables. These tables contain the raw XML for a
 193 number of DTDs that are not handled individually. This is partially
 194 for backwards-compatibility with a legacy implementation, but is
 195 mostly a stopgap due to a lack of resources at the moment. These two
 196 tables (game_info and sport_info) still possess timestamps that allow
 197 us to prune old data.
 198 .P
 199 UML diagrams of the resulting database schema for each XML document
 200 type are provided with the \fBhtsn-import\fR documentation.
 201
 202 .SH XML Schema Oddities
 203 .P
 204 There are a number of problems with the XML on the wire. Even if we
 205 construct the DTDs ourselves, the results are sometimes
 206 inconsistent. Here we document a few of them.
 207
 208 .IP \[bu] 2
 209 Odds_XML.dtd
 210
 211 The <Notes> elements here are supposed to be associated with a set of
 212 <Game> elements, but since the pair
 213 (<Notes>...</Notes><Game>...</Game>) can appear zero or more times,
 214 this leads to ambiguity in parsing. We therefore ignore the notes
 215 entirely (although a hack is employed to facilitate parsing).
 216
 217 .IP \[bu]
 218 weatherxml.dtd
 219
 220 There appear to be two types of weather documents; the first has
 221 <listing> contained within <forecast> and the second has <forecast>
 222 contained within <listing>. While it would be possible to parse both,
 223 it would greatly complicate things. The first form is more common, so
 224 that's all we support for now.
 225
 226 .SH OPTIONS
 227
 228 .IP \fB\-\-backend\fR,\ \fB\-b\fR
 229 The RDBMS backend to use. Valid choices are \fISqlite\fR and
 230 \fIPostgres\fR. Capitalization is important, sorry.
 231
 232 Default: Sqlite
 233
 234 .IP \fB\-\-connection-string\fR,\ \fB\-c\fR
 235 The connection string used for connecting to the database backend
 236 given by the \fB\-\-backend\fR option. The default is appropriate for
 237 the \fISqlite\fR backend.
 238
 239 Default: \(dq:memory:\(dq
 240
 241 .IP \fB\-\-log-file\fR
 242 If you specify a file here, logs will be written to it (possibly in
 243 addition to syslog). Can be either a relative or absolute path. It
 244 will not be auto-rotated; use something like logrotate for that.
 245
 246 Default: none
 247
 248 .IP \fB\-\-log-level\fR
 249 How verbose should the logs be? We log notifications at four levels:
 250 DEBUG, INFO, WARN, and ERROR. Specify the \(dqmost boring\(dq level of
 251 notifications you would like to receive (in all-caps); more
 252 interesting notifications will be logged as well. The debug output is
 253 extremely verbose and will not be written to syslog even if you try.
 254
 255 Default: INFO
 256
 257 .IP \fB\-\-remove\fR,\ \fB\-r\fR
 258 Remove successfully processed files. If you enable this, you can see
 259 at a glance which XML files are not being processed, because they're
 260 all that should be left.
 261
 262 Default: disabled
 263
 264 .IP \fB\-\-syslog\fR,\ \fB\-s\fR
 265 Enable logging to syslog. On Windows this will attempt to communicate
 266 (over UDP) with a syslog daemon on localhost, which will most likely
 267 not work.
 268
 269 Default: disabled
 270
 271 .SH CONFIGURATION FILE
 272 .P
 273 Any of the command-line options mentioned above can be specified in a
 274 configuration file instead. We first look for \(dqhtsn-importrc\(dq in
 275 the system configuration directory. We then look for a file named
 276 \(dq.htsn-importrc\(dq in the user's home directory. The latter will
 277 override the former.
 278 .P
 279 The user's home directory is simply $HOME on Unix; on Windows it's
 280 wherever %APPDATA% points. The system configuration directory is
 281 determined by Cabal; the \(dqsysconfdir\(dq parameter during the
 282 \(dqconfigure\(dq step is used.
 283 .P
 284 The file's syntax is given by examples in the htsn-importrc.example file
 285 (included with \fBhtsn-import\fR).
 286 .P
 287 Options specified on the command-line override those in either
 288 configuration file.
 289
 290 .SH EXAMPLES
 291 .IP \[bu] 2
 292 Import newsxml.xml into a preexisting sqlite database named \(dqfoo.sqlite3\(dq:
 293
 294 .nf
 295 .I $ htsn-import --connection-string='foo.sqlite3' \\\\
 296 .I "              test/xml/newsxml.xml"
 297 Successfully imported test/xml/newsxml.xml.
 298 Imported 1 document(s) total.
 299 .fi
 300 .IP \[bu]
 301 Repeat the previous example, but delete newsxml.xml afterwards:
 302
 303 .nf
 304 .I $ htsn-import --connection-string='foo.sqlite3' \\\\
 305 .I "              --remove test/xml/newsxml.xml"
 306 Successfully imported test/xml/newsxml.xml.
 307 Imported 1 document(s) total.
 308 Removed processed file test/xml/newsxml.xml.
 309 .fi
 310 .IP \[bu]
 311 Use a Postgres database instead of the default Sqlite. This assumes
 312 that you have a database named \(dqhtsn\(dq accessible to user
 313 \(dqpostgres\(dq locally:
 314
 315 .nf
 316 .I $ htsn-import --connection-string='dbname=htsn user=postgres' \\\\
 317 .I "              --backend=Postgres test/xml/newsxml.xml"
 318 Successfully imported test/xml/newsxml.xml.
 319 Imported 1 document(s) total.
 320 .fi
 321
 322 .SH BUGS
 323
 324 .P
 325 Send bugs to michael@orlitzky.com.