Changeset 15836 for gsdl/trunk/lib/sqlitedbclass.cpp

Timestamp:

2008-05-30T16:00:47+12:00 (16 years ago)

Author:

mdewsnip

Message:

(Adding dynamic classifiers) Not sure if this is necessarily the best place to do this, but added the ability to request the documents from a "get_documents_with_metadata_value()" call to be sorted based on a certain metadata element. Thanks to John Thompson for the SQL statement help.

File:

• gsdl/trunk/lib/sqlitedbclass.cpp (modified) (2 diffs)

gsdl/trunk/lib/sqlitedbclass.cpp

@@ -100 +100 @@
 // returns array of document OIDs
 text_tarray sqlitedbclass::get_documents_with_metadata_value (const text_t &metadata_element_name,
-                                  const text_t &metadata_value)
+                                  const text_t &metadata_value,
+                                  const text_t &sort_by_metadata_element_name)
 {
   text_tarray document_OIDs;
@@ -111 +112 @@
 
   // Get the entries in the "document_metadata" table where the element and value matches those specified
-  text_t sql_cmd = "SELECT docOID FROM document_metadata WHERE element='" + metadata_element_name + "' AND value='" + metadata_value + "'";
+  text_t sql_cmd;
+  if (sort_by_metadata_element_name == "")
+  {
+    // No sorting required
+    sql_cmd = "SELECT docOID FROM document_metadata WHERE element='" + metadata_element_name + "' AND value='" + metadata_value + "'";
+  }
+  else
+  {
+    // Sort the documents by a certain metadata element
+    // John Thompson thinks this may not be the most efficient solution, and recommends using ON instead of WHERE
+    sql_cmd = "SELECT b.docOID FROM document_metadata AS a LEFT JOIN document_metadata AS b USING (docOID) WHERE a.element='" + metadata_element_name + "' AND a.value='" + metadata_value + "' AND b.element='" + sort_by_metadata_element_name + "' ORDER BY b.value";
+  }
   vector<text_tmap> sql_results;
   if (!sqlgetarray(sql_cmd, sql_results) || sql_results.size() == 0)