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 146 database schema make it possible to delete only the outdated top-level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