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 .RE
 124 .P
 125 The GameInfo and SportInfo types do not have their own top-level
 126 tables in the database. Instead, their raw XML is stored in either the
 127 \(dqgame_info\(dq or \(dqsport_info\(dq table respectively.
 128
 129 .SH DATABASE SCHEMA
 130 .P
 131 At the top level (with two notable exceptions), we have one table for
 132 each of the XML document types that we import. For example, the
 133 documents corresponding to \fInewsxml.dtd\fR will have a table called
 134 \(dqnews\(dq. All top-level tables contain two important fields,
 135 \(dqxml_file_id\(dq and \(dqtime_stamp\(dq. The former is unique and
 136 prevents us from inserting the same data twice. The time stamp on the
 137 other hand lets us know when the data is old and can be removed. The
 138 database schema make it possible to delete only the outdated top-level
 139 records; all transient children should be removed by triggers.
 140 .P
 141 These top-level tables will often have children. For example, each
 142 news item has zero or more locations associated with it. The child
 143 table will be named <parent>_<children>, which in this case
 144 corresponds to \(dqnews_locations\(dq.
 145 .P
 146 To relate the two, a third table may exist with name
 147 <parent>__<child>. Note the two underscores. This prevents ambiguity
 148 when the child table itself contains underscores. The table joining
 149 \(dqnews\(dq with \(dqnews_locations\(dq is thus called
 150 \(dqnews__news_locations\(dq. This is necessary when the child table
 151 has a unique constraint; we don't want to blindly insert duplicate
 152 records keyed to the parent. Instead we'd like to use the third table
 153 to map an existing child to the new parent.
 154 .P
 155 Where it makes sense, children are kept unique to prevent pointless
 156 duplication. This slows down inserts, and speeds up reads (which are
 157 much more frequent). There is a tradeoff to be made, however. For a
 158 table with a small, fixed upper bound on the number of rows (like
 159 \(dqodds_casinos\(dq), there is great benefit to de-duplication. The
 160 total number of rows stays small, so inserts are still quick, and many
 161 duplicate rows are eliminated.
 162 .P
 163 But, with a table like \(dqodds_games\(dq, the number of games grows
 164 quickly and without bound. It is therefore more beneficial to be able
 165 to delete the old games (through an ON DELETE CASCADE, tied to
 166 \(dqodds\(dq) than it is to eliminate duplication. A table like
 167 \(dqnews_locations\(dq is somewhere in-between. It is hoped that the
 168 unique constraint in the top-level table's \(dqxml_file_id\(dq will
 169 prevent duplication in this case anyway.
 170 .P
 171 The aforementioned exceptions are the \(dqgame_info\(dq and
 172 \(dqsport_info\(dq tables. These tables contain the raw XML for a
 173 number of DTDs that are not handled individually. This is partially
 174 for backwards-compatibility with a legacy implementation, but is
 175 mostly a stopgap due to a lack of resources at the moment. These two
 176 tables (game_info and sport_info) still possess timestamps that allow
 177 us to prune old data.
 178 .P
 179 UML diagrams of the resulting database schema for each XML document
 180 type are provided with the \fBhtsn-import\fR documentation.
 181
 182 .SH XML Schema Oddities
 183 .P
 184 There are a number of problems with the XML on the wire. Even if we
 185 construct the DTDs ourselves, the results are sometimes
 186 inconsistent. Here we document a few of them.
 187
 188 .IP \[bu] 2
 189 Odds_XML.dtd
 190
 191 The <Notes> elements here are supposed to be associated with a set of
 192 <Game> elements, but since the pair
 193 (<Notes>...</Notes><Game>...</Game>) can appear zero or more times,
 194 this leads to ambiguity in parsing. We therefore ignore the notes
 195 entirely (although a hack is employed to facilitate parsing).
 196
 197 .IP \[bu]
 198 weatherxml.dtd
 199
 200 There appear to be two types of weather documents; the first has
 201 <listing> contained within <forecast> and the second has <forecast>
 202 contained within <listing>. While it would be possible to parse both,
 203 it would greatly complicate things. The first form is more common, so
 204 that's all we support for now.
 205
 206 .SH OPTIONS
 207
 208 .IP \fB\-\-backend\fR,\ \fB\-b\fR
 209 The RDBMS backend to use. Valid choices are \fISqlite\fR and
 210 \fIPostgres\fR. Capitalization is important, sorry.
 211
 212 Default: Sqlite
 213
 214 .IP \fB\-\-connection-string\fR,\ \fB\-c\fR
 215 The connection string used for connecting to the database backend
 216 given by the \fB\-\-backend\fR option. The default is appropriate for
 217 the \fISqlite\fR backend.
 218
 219 Default: \(dq:memory:\(dq
 220
 221 .IP \fB\-\-log-file\fR
 222 If you specify a file here, logs will be written to it (possibly in
 223 addition to syslog). Can be either a relative or absolute path. It
 224 will not be auto-rotated; use something like logrotate for that.
 225
 226 Default: none
 227
 228 .IP \fB\-\-log-level\fR
 229 How verbose should the logs be? We log notifications at four levels:
 230 DEBUG, INFO, WARN, and ERROR. Specify the \(dqmost boring\(dq level of
 231 notifications you would like to receive (in all-caps); more
 232 interesting notifications will be logged as well. The debug output is
 233 extremely verbose and will not be written to syslog even if you try.
 234
 235 Default: INFO
 236
 237 .IP \fB\-\-remove\fR,\ \fB\-r\fR
 238 Remove successfully processed files. If you enable this, you can see
 239 at a glance which XML files are not being processed, because they're
 240 all that should be left.
 241
 242 Default: disabled
 243
 244 .IP \fB\-\-syslog\fR,\ \fB\-s\fR
 245 Enable logging to syslog. On Windows this will attempt to communicate
 246 (over UDP) with a syslog daemon on localhost, which will most likely
 247 not work.
 248
 249 Default: disabled
 250
 251 .SH CONFIGURATION FILE
 252 .P
 253 Any of the command-line options mentioned above can be specified in a
 254 configuration file instead. We first look for \(dqhtsn-importrc\(dq in
 255 the system configuration directory. We then look for a file named
 256 \(dq.htsn-importrc\(dq in the user's home directory. The latter will
 257 override the former.
 258 .P
 259 The user's home directory is simply $HOME on Unix; on Windows it's
 260 wherever %APPDATA% points. The system configuration directory is
 261 determined by Cabal; the \(dqsysconfdir\(dq parameter during the
 262 \(dqconfigure\(dq step is used.
 263 .P
 264 The file's syntax is given by examples in the htsn-importrc.example file
 265 (included with \fBhtsn-import\fR).
 266 .P
 267 Options specified on the command-line override those in either
 268 configuration file.
 269
 270 .SH EXAMPLES
 271 .IP \[bu] 2
 272 Import newsxml.xml into a preexisting sqlite database named \(dqfoo.sqlite3\(dq:
 273
 274 .nf
 275 .I $ htsn-import --connection-string='foo.sqlite3' \\\\
 276 .I "              test/xml/newsxml.xml"
 277 Successfully imported test/xml/newsxml.xml.
 278 Imported 1 document(s) total.
 279 .fi
 280 .IP \[bu]
 281 Repeat the previous example, but delete newsxml.xml afterwards:
 282
 283 .nf
 284 .I $ htsn-import --connection-string='foo.sqlite3' \\\\
 285 .I "              --remove test/xml/newsxml.xml"
 286 Successfully imported test/xml/newsxml.xml.
 287 Imported 1 document(s) total.
 288 Removed processed file test/xml/newsxml.xml.
 289 .fi
 290 .IP \[bu]
 291 Use a Postgres database instead of the default Sqlite. This assumes
 292 that you have a database named \(dqhtsn\(dq accessible to user
 293 \(dqpostgres\(dq locally:
 294
 295 .nf
 296 .I $ htsn-import --connection-string='dbname=htsn user=postgres' \\\\
 297 .I "              --backend=Postgres test/xml/newsxml.xml"
 298 Successfully imported test/xml/newsxml.xml.
 299 Imported 1 document(s) total.
 300 .fi
 301
 302 .SH BUGS
 303
 304 .P
 305 Send bugs to michael@orlitzky.com.