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 144 database schema make it possible to delete only the outdated top-level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