Add an Database#sqlite_version method when connecting to SQLite, used…

… to determine feature support

Currently, the only feature that uses this is the savepoint support,
which now checks that the SQLite version is at least 3.6.8 before
attempting to use savepoints.

CHANGELOG

@@ -1,5 +1,7 @@
 === HEAD
 
+* Add an Database#sqlite_version method when connecting to SQLite, used to determine feature support (jeremyevans)
+
 * Fix rolling back transactions when connecting to Oracle via JDBC (jeremyevans)
 
 * Fix syntax errors when connecting to MSSQL via the dbi adapter (jeremyevans) (#292)

lib/sequel/adapters/shared/sqlite.rb

@@ -65,9 +65,21 @@ def pragma_set(name, value)
         execute_ddl("PRAGMA #{name} = #{value}")
       end
 
-      # SQLite supports savepoints
+      # The version of the server as an integer, where 3.6.19 = 30619.
+      # If the server version can't be determined, 0 is used.
+      def sqlite_version
+        return @server_version if defined?(@server_version)
+        @server_version = begin
+          v = get{sqlite_version{}}
+          [10000, 100, 1].zip(v.split('.')).inject(0){|a, m| a + m[0] * Integer(m[1])}
+        rescue
+          0
+        end
+      end
+
+      # SQLite 3.6.8+ supports savepoints. 
       def supports_savepoints?
-        true
+        sqlite_version >= 30608
       end
 
       # A symbol signifying the value of the synchronous PRAGMA.