Difference between revisions of "Semantic MediaWiki/data"

Revision as of 23:08, 10 July 2020

Tables

All of this information has been reverse-engineered, mostly from examination of data in a single SMW instance. I was not able to find any data-structure documentation in the official code docs.

Note that the schema version numbers are generally higher than the corresponding SMW version^[1].

schema version 3

These are present in SMW version 1.9 alpha^[1]:

schema version 2

These were present in SMW version 1.7, and may also be valid for 1.8 (but not 1.9):

/smw_atts2: relationships where the value is numerically/logically significant, or a "string" (non-page type)
/smw_conc2: not sure; probably concepts
/smw_conccache: not sure; presumably a cache for concepts
/smw_ids: assigns IDs to all properties, and values that map to a (potential) wiki page
/smw_inst2: not sure
/smw_redi2: not sure; redirects?
/smw_rels2: relationships where the value refers to a (potential) wiki page
/smw_spec2: URLs to SWiVT specs
/smw_subp2: not sure; sub-property map?
/smw_subs2: not sure; looks like a mapping of categories to sub-categories
/smw_text2: relationships where the value is a long text/data blob

Core tables are boldfaced; the others seem to be primarily for optimization or auxiliary purposes.

Explanations

Semantic relationships are defined in /smw rels2, /smw_text2, and /smw_atts2.
Correspondence between SMW entities (property names and some property values) and MediaWiki pages is defined in /smw_ids
Presumably the type of storage can be determined by looking up the SMW ID in /smw_spec2, making it unnecessary to check multiple tables (rels2, text2, atts2) for each property. but it does not seem to have been designed for this purpose.

Footnote

↑ ^1.0 ^1.1 I'm presuming that there was a schema version 1 based on the naming of the version 2 tables (they all end in '2'), but this may be incorrect. In any case, schema version 2 corresponds approximately to SMW v1.x, and schema version 3 to SMW 2.x (and some high-numbered 1.x beta releases).

[versions-1] 1.0 ^1.1 I'm presuming that there was a schema version 1 based on the naming of the version 2 tables (they all end in '2'), but this may be incorrect. In any case, schema version 2 corresponds approximately to SMW v1.x, and schema version 3 to SMW 2.x (and some high-numbered 1.x beta releases).

[1]

@@ Line 1: / Line 1: @@
 ==Tables==
-I'm presuming that there was a schema version 1 based on the naming of the version 2 tables (they all end in '2'), but this may be incorrect. In any case, schema version 2 corresponds approximately to SMW v1.x, and schema version 3 to SMW 2.x (and some high-numbered 1.x beta releases).
+All of this information has been reverse-engineered, mostly from examination of data in a single SMW instance. I was not able to find any data-structure documentation in the [https://doc.semantic-mediawiki.org/index.html official code docs].
+Note that the ''schema'' version numbers are generally higher than the corresponding SMW version<ref name=versions />.
 {|
 |-
 | valign=top |
 ===schema version 3===
-These are present in SMW version <s>1.9 alpha</s> (I think I ''must'' have meant 2.9 alpha):
+These are present in SMW version 1.9 alpha<ref name=versions />:
-* [[/smw_di_*]]:
+* '''[[/smw_di_*]]''':
 ** [[/smw_di_blob]]
 ** [[/smw_di_bool]]
@@ Line 63: / Line 65: @@
 * Presumably the type of storage can be determined by looking up the SMW ID in [[/smw_spec2]], making it unnecessary to check multiple tables (rels2, text2, atts2) for each property. but it does not seem to have been designed for this purpose.
 |}
+==Footnote==
+<references>
+<ref name=versions>I'm presuming that there was a schema version 1 based on the naming of the version 2 tables (they all end in '2'), but this may be incorrect. In any case, schema version 2 corresponds approximately to SMW v1.x, and schema version 3 to SMW 2.x (and some high-numbered 1.x beta releases).</ref>
+</references>