4 htsn-import \- Import XML files from The Sports Network into an RDBMS.
8 \fBhtsn-import\fR [OPTIONS] [FILES]
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?
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
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.
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.
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.
46 .SH SUPPORTED DOCUMENT TYPES
48 The XML document types obtained from the feed are uniquely identified
49 by their DTDs. We currently support documents with the following DTDs:
51 AutoRacingResultsXML.dtd
53 Auto_Racing_Schedule_XML.dtd
57 Injuries_Detail_XML.dtd
78 Matchup_NBA_NHL_XML.dtd
80 MLB_Gaming_Matchup_XML.dtd
90 NBA_Gaming_Matchup_XML.dtd
92 NBA_Playoff_Matchup_XML.dtd
98 NCAA_FB_Preview_XML.dtd
100 NFL_NCAA_FB_Matchup_XML.dtd
108 WorldBaseballPreviewXML.dtd
116 Cbask_All_Tourn_Teams_XML.dtd
124 Cbask_Conf_Standings_XML.dtd
126 Cbask_DivII_III_Indv_Stats_XML.dtd
128 Cbask_DivII_Team_Stats_XML.dtd
130 Cbask_DivIII_Team_Stats_XML.dtd
138 Cbask_Indv_Scoring_XML.dtd
144 CBASK_ReboundsXML.dtd
146 CBASK_ScoringLeadersXML.dtd
148 Cbask_Team_ThreePT_Made_XML.dtd
150 Cbask_Team_ThreePT_PCT_XML.dtd
152 Cbask_Team_Win_Pct_XML.dtd
154 Cbask_Top_Twenty_Five_XML.dtd
156 CBASK_TopTwentyFiveResult_XML.dtd
158 Cbask_Tourn_Awards_XML.dtd
160 Cbask_Tourn_Champs_XML.dtd
162 Cbask_Tourn_Indiv_XML.dtd
164 Cbask_Tourn_Leaders_XML.dtd
166 Cbask_Tourn_MVP_XML.dtd
168 Cbask_Tourn_Records_XML.dtd
170 LeagueScheduleXML.dtd
174 Minor_Baseball_League_Leaders_XML.dtd
176 Minor_Baseball_Standings_XML.dtd
178 Minor_Baseball_Transactions_XML.dtd
182 mlbdoublesleadersxml.dtd
184 MLBGamesPlayedXML.dtd
190 mlbhitsleadersxml.dtd
208 mlbrunsleadersxml.dtd
216 mlbsluggingpctxml.dtd
220 mlbstandxml_preseason.dtd
225 The GameInfo and SportInfo types do not have their own top-level
226 tables in the database. Instead, their raw XML is stored in either the
227 \(dqgame_info\(dq or \(dqsport_info\(dq table respectively.
231 At the top level (with two notable exceptions), we have one table for
232 each of the XML document types that we import. For example, the
233 documents corresponding to \fInewsxml.dtd\fR will have a table called
234 \(dqnews\(dq. All top-level tables contain two important fields,
235 \(dqxml_file_id\(dq and \(dqtime_stamp\(dq. The former is unique and
236 prevents us from inserting the same data twice. The time stamp on the
237 other hand lets us know when the data is old and can be removed. The
238 database schema make it possible to delete only the outdated top-level
239 records; all transient children should be removed by triggers.
241 These top-level tables will often have children. For example, each
242 news item has zero or more locations associated with it. The child
243 table will be named <parent>_<children>, which in this case
244 corresponds to \(dqnews_locations\(dq.
246 To relate the two, a third table may exist with name
247 <parent>__<child>. Note the two underscores. This prevents ambiguity
248 when the child table itself contains underscores. The table joining
249 \(dqnews\(dq with \(dqnews_locations\(dq is thus called
250 \(dqnews__news_locations\(dq. This is necessary when the child table
251 has a unique constraint; we don't want to blindly insert duplicate
252 records keyed to the parent. Instead we'd like to use the third table
253 to map an existing child to the new parent.
255 Where it makes sense, children are kept unique to prevent pointless
256 duplication. This slows down inserts, and speeds up reads (which are
257 much more frequent). There is a tradeoff to be made, however. For a
258 table with a small, fixed upper bound on the number of rows (like
259 \(dqodds_casinos\(dq), there is great benefit to de-duplication. The
260 total number of rows stays small, so inserts are still quick, and many
261 duplicate rows are eliminated.
263 But, with a table like \(dqodds_games\(dq, the number of games grows
264 quickly and without bound. It is therefore more beneficial to be able
265 to delete the old games (through an ON DELETE CASCADE, tied to
266 \(dqodds\(dq) than it is to eliminate duplication. A table like
267 \(dqnews_locations\(dq is somewhere in-between. It is hoped that the
268 unique constraint in the top-level table's \(dqxml_file_id\(dq will
269 prevent duplication in this case anyway.
271 The aforementioned exceptions are the \(dqgame_info\(dq and
272 \(dqsport_info\(dq tables. These tables contain the raw XML for a
273 number of DTDs that are not handled individually. This is partially
274 for backwards-compatibility with a legacy implementation, but is
275 mostly a stopgap due to a lack of resources at the moment. These two
276 tables (game_info and sport_info) still possess timestamps that allow
277 us to prune old data.
279 UML diagrams of the resulting database schema for each XML document
280 type are provided with the \fBhtsn-import\fR documentation.
282 .SH XML Schema Oddities
284 There are a number of problems with the XML on the wire. Even if we
285 construct the DTDs ourselves, the results are sometimes
286 inconsistent. Here we document a few of them.
291 The <Notes> elements here are supposed to be associated with a set of
292 <Game> elements, but since the pair
293 (<Notes>...</Notes><Game>...</Game>) can appear zero or more times,
294 this leads to ambiguity in parsing. We therefore ignore the notes
295 entirely (although a hack is employed to facilitate parsing).
300 There appear to be two types of weather documents; the first has
301 <listing> contained within <forecast> and the second has <forecast>
302 contained within <listing>. While it would be possible to parse both,
303 it would greatly complicate things. The first form is more common, so
304 that's all we support for now.
308 .IP \fB\-\-backend\fR,\ \fB\-b\fR
309 The RDBMS backend to use. Valid choices are \fISqlite\fR and
310 \fIPostgres\fR. Capitalization is important, sorry.
314 .IP \fB\-\-connection-string\fR,\ \fB\-c\fR
315 The connection string used for connecting to the database backend
316 given by the \fB\-\-backend\fR option. The default is appropriate for
317 the \fISqlite\fR backend.
319 Default: \(dq:memory:\(dq
321 .IP \fB\-\-log-file\fR
322 If you specify a file here, logs will be written to it (possibly in
323 addition to syslog). Can be either a relative or absolute path. It
324 will not be auto-rotated; use something like logrotate for that.
328 .IP \fB\-\-log-level\fR
329 How verbose should the logs be? We log notifications at four levels:
330 DEBUG, INFO, WARN, and ERROR. Specify the \(dqmost boring\(dq level of
331 notifications you would like to receive (in all-caps); more
332 interesting notifications will be logged as well. The debug output is
333 extremely verbose and will not be written to syslog even if you try.
337 .IP \fB\-\-remove\fR,\ \fB\-r\fR
338 Remove successfully processed files. If you enable this, you can see
339 at a glance which XML files are not being processed, because they're
340 all that should be left.
344 .IP \fB\-\-syslog\fR,\ \fB\-s\fR
345 Enable logging to syslog. On Windows this will attempt to communicate
346 (over UDP) with a syslog daemon on localhost, which will most likely
351 .SH CONFIGURATION FILE
353 Any of the command-line options mentioned above can be specified in a
354 configuration file instead. We first look for \(dqhtsn-importrc\(dq in
355 the system configuration directory. We then look for a file named
356 \(dq.htsn-importrc\(dq in the user's home directory. The latter will
359 The user's home directory is simply $HOME on Unix; on Windows it's
360 wherever %APPDATA% points. The system configuration directory is
361 determined by Cabal; the \(dqsysconfdir\(dq parameter during the
362 \(dqconfigure\(dq step is used.
364 The file's syntax is given by examples in the htsn-importrc.example file
365 (included with \fBhtsn-import\fR).
367 Options specified on the command-line override those in either
372 Import newsxml.xml into a preexisting sqlite database named \(dqfoo.sqlite3\(dq:
375 .I $ htsn-import --connection-string='foo.sqlite3' \\\\
376 .I " test/xml/newsxml.xml"
377 Successfully imported test/xml/newsxml.xml.
378 Imported 1 document(s) total.
381 Repeat the previous example, but delete newsxml.xml afterwards:
384 .I $ htsn-import --connection-string='foo.sqlite3' \\\\
385 .I " --remove test/xml/newsxml.xml"
386 Successfully imported test/xml/newsxml.xml.
387 Imported 1 document(s) total.
388 Removed processed file test/xml/newsxml.xml.
391 Use a Postgres database instead of the default Sqlite. This assumes
392 that you have a database named \(dqhtsn\(dq accessible to user
393 \(dqpostgres\(dq locally:
396 .I $ htsn-import --connection-string='dbname=htsn user=postgres' \\\\
397 .I " --backend=Postgres test/xml/newsxml.xml"
398 Successfully imported test/xml/newsxml.xml.
399 Imported 1 document(s) total.
405 Send bugs to michael@orlitzky.com.