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 .RE
 134 .P
 135 The GameInfo and SportInfo types do not have their own top-level
 136 tables in the database. Instead, their raw XML is stored in either the
 137 \(dqgame_info\(dq or \(dqsport_info\(dq table respectively.
 138
 139 .SH DATABASE SCHEMA
 140 .P
 141 At the top level (with two notable exceptions), we have one table for
 142 each of the XML document types that we import. For example, the
 143 documents corresponding to \fInewsxml.dtd\fR will have a table called
 144 \(dqnews\(dq. All top-level tables contain two important fields,
 145 \(dqxml_file_id\(dq and \(dqtime_stamp\(dq. The former is unique and
 146 prevents us from inserting the same data twice. The time stamp on the
 147 other hand lets us know when the data is old and can be removed. The
 148 database schema make it possible to delete only the outdated top-level
 149 records; all transient children should be removed by triggers.
 150 .P
 151 These top-level tables will often have children. For example, each
 152 news item has zero or more locations associated with it. The child
 153 table will be named <parent>_<children>, which in this case
 154 corresponds to \(dqnews_locations\(dq.
 155 .P
 156 To relate the two, a third table may exist with name
 157 <parent>__<child>. Note the two underscores. This prevents ambiguity
 158 when the child table itself contains underscores. The table joining
 159 \(dqnews\(dq with \(dqnews_locations\(dq is thus called
 160 \(dqnews__news_locations\(dq. This is necessary when the child table
 161 has a unique constraint; we don't want to blindly insert duplicate
 162 records keyed to the parent. Instead we'd like to use the third table
 163 to map an existing child to the new parent.
 164 .P
 165 Where it makes sense, children are kept unique to prevent pointless
 166 duplication. This slows down inserts, and speeds up reads (which are
 167 much more frequent). There is a tradeoff to be made, however. For a
 168 table with a small, fixed upper bound on the number of rows (like
 169 \(dqodds_casinos\(dq), there is great benefit to de-duplication. The
 170 total number of rows stays small, so inserts are still quick, and many
 171 duplicate rows are eliminated.
 172 .P
 173 But, with a table like \(dqodds_games\(dq, the number of games grows
 174 quickly and without bound. It is therefore more beneficial to be able
 175 to delete the old games (through an ON DELETE CASCADE, tied to
 176 \(dqodds\(dq) than it is to eliminate duplication. A table like
 177 \(dqnews_locations\(dq is somewhere in-between. It is hoped that the
 178 unique constraint in the top-level table's \(dqxml_file_id\(dq will
 179 prevent duplication in this case anyway.
 180 .P
 181 The aforementioned exceptions are the \(dqgame_info\(dq and
 182 \(dqsport_info\(dq tables. These tables contain the raw XML for a
 183 number of DTDs that are not handled individually. This is partially
 184 for backwards-compatibility with a legacy implementation, but is
 185 mostly a stopgap due to a lack of resources at the moment. These two
 186 tables (game_info and sport_info) still possess timestamps that allow
 187 us to prune old data.
 188 .P
 189 UML diagrams of the resulting database schema for each XML document
 190 type are provided with the \fBhtsn-import\fR documentation.
 191
 192 .SH XML Schema Oddities
 193 .P
 194 There are a number of problems with the XML on the wire. Even if we
 195 construct the DTDs ourselves, the results are sometimes
 196 inconsistent. Here we document a few of them.
 197
 198 .IP \[bu] 2
 199 Odds_XML.dtd
 200
 201 The <Notes> elements here are supposed to be associated with a set of
 202 <Game> elements, but since the pair
 203 (<Notes>...</Notes><Game>...</Game>) can appear zero or more times,
 204 this leads to ambiguity in parsing. We therefore ignore the notes
 205 entirely (although a hack is employed to facilitate parsing).
 206
 207 .IP \[bu]
 208 weatherxml.dtd
 209
 210 There appear to be two types of weather documents; the first has
 211 <listing> contained within <forecast> and the second has <forecast>
 212 contained within <listing>. While it would be possible to parse both,
 213 it would greatly complicate things. The first form is more common, so
 214 that's all we support for now.
 215
 216 .SH OPTIONS
 217
 218 .IP \fB\-\-backend\fR,\ \fB\-b\fR
 219 The RDBMS backend to use. Valid choices are \fISqlite\fR and
 220 \fIPostgres\fR. Capitalization is important, sorry.
 221
 222 Default: Sqlite
 223
 224 .IP \fB\-\-connection-string\fR,\ \fB\-c\fR
 225 The connection string used for connecting to the database backend
 226 given by the \fB\-\-backend\fR option. The default is appropriate for
 227 the \fISqlite\fR backend.
 228
 229 Default: \(dq:memory:\(dq
 230
 231 .IP \fB\-\-log-file\fR
 232 If you specify a file here, logs will be written to it (possibly in
 233 addition to syslog). Can be either a relative or absolute path. It
 234 will not be auto-rotated; use something like logrotate for that.
 235
 236 Default: none
 237
 238 .IP \fB\-\-log-level\fR
 239 How verbose should the logs be? We log notifications at four levels:
 240 DEBUG, INFO, WARN, and ERROR. Specify the \(dqmost boring\(dq level of
 241 notifications you would like to receive (in all-caps); more
 242 interesting notifications will be logged as well. The debug output is
 243 extremely verbose and will not be written to syslog even if you try.
 244
 245 Default: INFO
 246
 247 .IP \fB\-\-remove\fR,\ \fB\-r\fR
 248 Remove successfully processed files. If you enable this, you can see
 249 at a glance which XML files are not being processed, because they're
 250 all that should be left.
 251
 252 Default: disabled
 253
 254 .IP \fB\-\-syslog\fR,\ \fB\-s\fR
 255 Enable logging to syslog. On Windows this will attempt to communicate
 256 (over UDP) with a syslog daemon on localhost, which will most likely
 257 not work.
 258
 259 Default: disabled
 260
 261 .SH CONFIGURATION FILE
 262 .P
 263 Any of the command-line options mentioned above can be specified in a
 264 configuration file instead. We first look for \(dqhtsn-importrc\(dq in
 265 the system configuration directory. We then look for a file named
 266 \(dq.htsn-importrc\(dq in the user's home directory. The latter will
 267 override the former.
 268 .P
 269 The user's home directory is simply $HOME on Unix; on Windows it's
 270 wherever %APPDATA% points. The system configuration directory is
 271 determined by Cabal; the \(dqsysconfdir\(dq parameter during the
 272 \(dqconfigure\(dq step is used.
 273 .P
 274 The file's syntax is given by examples in the htsn-importrc.example file
 275 (included with \fBhtsn-import\fR).
 276 .P
 277 Options specified on the command-line override those in either
 278 configuration file.
 279
 280 .SH EXAMPLES
 281 .IP \[bu] 2
 282 Import newsxml.xml into a preexisting sqlite database named \(dqfoo.sqlite3\(dq:
 283
 284 .nf
 285 .I $ htsn-import --connection-string='foo.sqlite3' \\\\
 286 .I "              test/xml/newsxml.xml"
 287 Successfully imported test/xml/newsxml.xml.
 288 Imported 1 document(s) total.
 289 .fi
 290 .IP \[bu]
 291 Repeat the previous example, but delete newsxml.xml afterwards:
 292
 293 .nf
 294 .I $ htsn-import --connection-string='foo.sqlite3' \\\\
 295 .I "              --remove test/xml/newsxml.xml"
 296 Successfully imported test/xml/newsxml.xml.
 297 Imported 1 document(s) total.
 298 Removed processed file test/xml/newsxml.xml.
 299 .fi
 300 .IP \[bu]
 301 Use a Postgres database instead of the default Sqlite. This assumes
 302 that you have a database named \(dqhtsn\(dq accessible to user
 303 \(dqpostgres\(dq locally:
 304
 305 .nf
 306 .I $ htsn-import --connection-string='dbname=htsn user=postgres' \\\\
 307 .I "              --backend=Postgres test/xml/newsxml.xml"
 308 Successfully imported test/xml/newsxml.xml.
 309 Imported 1 document(s) total.
 310 .fi
 311
 312 .SH BUGS
 313
 314 .P
 315 Send bugs to michael@orlitzky.com.