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 Auto_Racing_Schedule_XML.dtd
  52 .IP \[bu]
  53 Heartbeat.dtd
  54 .IP \[bu]
  55 Injuries_Detail_XML.dtd
  56 .IP \[bu]
  57 injuriesxml.dtd
  58 .IP \[bu]
  59 newsxml.dtd
  60 .IP \[bu]
  61 Odds_XML.dtd
  62 .IP \[bu]
  63 scoresxml.dtd
  64 .IP \[bu]
  65 weatherxml.dtd
  66 .IP \[bu]
  67 GameInfo
  68 .RS
  69 .IP \[bu]
  70 CBASK_Lineup_XML.dtd
  71 .IP \[bu]
  72 cbaskpreviewxml.dtd
  73 .IP \[bu]
  74 cflpreviewxml.dtd
  75 .IP \[bu]
  76 Matchup_NBA_NHL_XML.dtd
  77 .IP \[bu]
  78 MLB_Gaming_Matchup_XML.dtd
  79 .IP \[bu]
  80 MLB_Lineup_XML.dtd
  81 .IP \[bu]
  82 MLB_Matchup_XML.dtd
  83 .IP \[bu]
  84 MLS_Preview_XML.dtd
  85 .IP \[bu]
  86 mlbpreviewxml.dtd
  87 .IP \[bu]
  88 NBA_Gaming_Matchup_XML.dtd
  89 .IP \[bu]
  90 NBA_Playoff_Matchup_XML.dtd
  91 .IP \[bu]
  92 NBALineupXML.dtd
  93 .IP \[bu]
  94 nbapreviewxml.dtd
  95 .IP \[bu]
  96 NCAA_FB_Preview_XML.dtd
  97 .IP \[bu]
  98 NFL_NCAA_FB_Matchup_XML.dtd
  99 .IP \[bu]
 100 nflpreviewxml.dtd
 101 .IP \[bu]
 102 nhlpreviewxml.dtd
 103 .IP \[bu]
 104 recapxml.dtd
 105 .IP \[bu]
 106 WorldBaseballPreviewXML.dtd
 107 .RE
 108 .IP \[bu]
 109 SportInfo
 110 .RS
 111 .IP \[bu]
 112 CBASK_3PPctXML.dtd
 113 .IP \[bu]
 114 Cbask_All_Tourn_Teams_XML.dtd
 115 .IP \[bu]
 116 CBASK_AssistsXML.dtd
 117 .IP \[bu]
 118 Cbask_Awards_XML.dtd
 119 .IP \[bu]
 120 CBASK_BlocksXML.dtd
 121 .RE
 122 .P
 123 The GameInfo and SportInfo types do not have their own top-level
 124 tables in the database. Instead, their raw XML is stored in either the
 125 \(dqgame_info\(dq or \(dqsport_info\(dq table respectively.
 126
 127 .SH DATABASE SCHEMA
 128 .P
 129 At the top level (with two notable exceptions), we have one table for
 130 each of the XML document types that we import. For example, the
 131 documents corresponding to \fInewsxml.dtd\fR will have a table called
 132 \(dqnews\(dq. All top-level tables contain two important fields,
 133 \(dqxml_file_id\(dq and \(dqtime_stamp\(dq. The former is unique and
 134 prevents us from inserting the same data twice. The time stamp on the
 135 other hand lets us know when the data is old and can be removed. The
 136 database schema make it possible to delete only the outdated top-level
 137 records; all transient children should be removed by triggers.
 138 .P
 139 These top-level tables will often have children. For example, each
 140 news item has zero or more locations associated with it. The child
 141 table will be named <parent>_<children>, which in this case
 142 corresponds to \(dqnews_locations\(dq.
 143 .P
 144 To relate the two, a third table may exist with name
 145 <parent>__<child>. Note the two underscores. This prevents ambiguity
 146 when the child table itself contains underscores. The table joining
 147 \(dqnews\(dq with \(dqnews_locations\(dq is thus called
 148 \(dqnews__news_locations\(dq. This is necessary when the child table
 149 has a unique constraint; we don't want to blindly insert duplicate
 150 records keyed to the parent. Instead we'd like to use the third table
 151 to map an existing child to the new parent.
 152 .P
 153 Where it makes sense, children are kept unique to prevent pointless
 154 duplication. This slows down inserts, and speeds up reads (which are
 155 much more frequent). There is a tradeoff to be made, however. For a
 156 table with a small, fixed upper bound on the number of rows (like
 157 \(dqodds_casinos\(dq), there is great benefit to de-duplication. The
 158 total number of rows stays small, so inserts are still quick, and many
 159 duplicate rows are eliminated.
 160 .P
 161 But, with a table like \(dqodds_games\(dq, the number of games grows
 162 quickly and without bound. It is therefore more beneficial to be able
 163 to delete the old games (through an ON DELETE CASCADE, tied to
 164 \(dqodds\(dq) than it is to eliminate duplication. A table like
 165 \(dqnews_locations\(dq is somewhere in-between. It is hoped that the
 166 unique constraint in the top-level table's \(dqxml_file_id\(dq will
 167 prevent duplication in this case anyway.
 168 .P
 169 The aforementioned exceptions are the \(dqgame_info\(dq and
 170 \(dqsport_info\(dq tables. These tables contain the raw XML for a
 171 number of DTDs that are not handled individually. This is partially
 172 for backwards-compatibility with a legacy implementation, but is
 173 mostly a stopgap due to a lack of resources at the moment. These two
 174 tables (game_info and sport_info) still possess timestamps that allow
 175 us to prune old data.
 176 .P
 177 UML diagrams of the resulting database schema for each XML document
 178 type are provided with the \fBhtsn-import\fR documentation.
 179
 180 .SH XML Schema Oddities
 181 .P
 182 There are a number of problems with the XML on the wire. Even if we
 183 construct the DTDs ourselves, the results are sometimes
 184 inconsistent. Here we document a few of them.
 185
 186 .IP \[bu] 2
 187 Odds_XML.dtd
 188
 189 The <Notes> elements here are supposed to be associated with a set of
 190 <Game> elements, but since the pair
 191 (<Notes>...</Notes><Game>...</Game>) can appear zero or more times,
 192 this leads to ambiguity in parsing. We therefore ignore the notes
 193 entirely (although a hack is employed to facilitate parsing).
 194
 195 .IP \[bu]
 196 weatherxml.dtd
 197
 198 There appear to be two types of weather documents; the first has
 199 <listing> contained within <forecast> and the second has <forecast>
 200 contained within <listing>. While it would be possible to parse both,
 201 it would greatly complicate things. The first form is more common, so
 202 that's all we support for now.
 203
 204 .SH OPTIONS
 205
 206 .IP \fB\-\-backend\fR,\ \fB\-b\fR
 207 The RDBMS backend to use. Valid choices are \fISqlite\fR and
 208 \fIPostgres\fR. Capitalization is important, sorry.
 209
 210 Default: Sqlite
 211
 212 .IP \fB\-\-connection-string\fR,\ \fB\-c\fR
 213 The connection string used for connecting to the database backend
 214 given by the \fB\-\-backend\fR option. The default is appropriate for
 215 the \fISqlite\fR backend.
 216
 217 Default: \(dq:memory:\(dq
 218
 219 .IP \fB\-\-log-file\fR
 220 If you specify a file here, logs will be written to it (possibly in
 221 addition to syslog). Can be either a relative or absolute path. It
 222 will not be auto-rotated; use something like logrotate for that.
 223
 224 Default: none
 225
 226 .IP \fB\-\-log-level\fR
 227 How verbose should the logs be? We log notifications at four levels:
 228 DEBUG, INFO, WARN, and ERROR. Specify the \(dqmost boring\(dq level of
 229 notifications you would like to receive (in all-caps); more
 230 interesting notifications will be logged as well. The debug output is
 231 extremely verbose and will not be written to syslog even if you try.
 232
 233 Default: INFO
 234
 235 .IP \fB\-\-remove\fR,\ \fB\-r\fR
 236 Remove successfully processed files. If you enable this, you can see
 237 at a glance which XML files are not being processed, because they're
 238 all that should be left.
 239
 240 Default: disabled
 241
 242 .IP \fB\-\-syslog\fR,\ \fB\-s\fR
 243 Enable logging to syslog. On Windows this will attempt to communicate
 244 (over UDP) with a syslog daemon on localhost, which will most likely
 245 not work.
 246
 247 Default: disabled
 248
 249 .SH CONFIGURATION FILE
 250 .P
 251 Any of the command-line options mentioned above can be specified in a
 252 configuration file instead. We first look for \(dqhtsn-importrc\(dq in
 253 the system configuration directory. We then look for a file named
 254 \(dq.htsn-importrc\(dq in the user's home directory. The latter will
 255 override the former.
 256 .P
 257 The user's home directory is simply $HOME on Unix; on Windows it's
 258 wherever %APPDATA% points. The system configuration directory is
 259 determined by Cabal; the \(dqsysconfdir\(dq parameter during the
 260 \(dqconfigure\(dq step is used.
 261 .P
 262 The file's syntax is given by examples in the htsn-importrc.example file
 263 (included with \fBhtsn-import\fR).
 264 .P
 265 Options specified on the command-line override those in either
 266 configuration file.
 267
 268 .SH EXAMPLES
 269 .IP \[bu] 2
 270 Import newsxml.xml into a preexisting sqlite database named \(dqfoo.sqlite3\(dq:
 271
 272 .nf
 273 .I $ htsn-import --connection-string='foo.sqlite3' \\\\
 274 .I "              test/xml/newsxml.xml"
 275 Successfully imported test/xml/newsxml.xml.
 276 Imported 1 document(s) total.
 277 .fi
 278 .IP \[bu]
 279 Repeat the previous example, but delete newsxml.xml afterwards:
 280
 281 .nf
 282 .I $ htsn-import --connection-string='foo.sqlite3' \\\\
 283 .I "              --remove test/xml/newsxml.xml"
 284 Successfully imported test/xml/newsxml.xml.
 285 Imported 1 document(s) total.
 286 Removed processed file test/xml/newsxml.xml.
 287 .fi
 288 .IP \[bu]
 289 Use a Postgres database instead of the default Sqlite. This assumes
 290 that you have a database named \(dqhtsn\(dq accessible to user
 291 \(dqpostgres\(dq locally:
 292
 293 .nf
 294 .I $ htsn-import --connection-string='dbname=htsn user=postgres' \\\\
 295 .I "              --backend=Postgres test/xml/newsxml.xml"
 296 Successfully imported test/xml/newsxml.xml.
 297 Imported 1 document(s) total.
 298 .fi
 299
 300 .SH BUGS
 301
 302 .P
 303 Send bugs to michael@orlitzky.com.