db.rb in picky-1.5.3

- old
+ new

@@ -1,7 +1,7 @@
 module Sources
-  
+
   # Describes a database source. Needs a SELECT statement
   # (with id in it), and a file option or the options from an AR config file.
   #
   # The select statement can be as complicated as you want,
   # as long as it has an id in it and as long as it can be
@@ -13,42 +13,48 @@
   #  Sources::DB.new('SELECT id, title, author, year FROM books', file: 'app/some_db.yml')
   #  Sources::DB.new('SELECT b.id, b.title, b.author, b.publishing_year as year FROM books b INNER JOIN ON ...', file: 'app/some_db.yml')
   #  Sources::DB.new('SELECT id, title, author, year FROM books', adapter: 'mysql', host:'localhost', ...)
   #
   class DB < Base
-    
+
     # The select statement that was passed in.
     #
     attr_reader :select_statement
-    
+
     # The database adapter.
     #
     attr_reader :database
-    
+
     # The database connection options that were either passed in or loaded from the given file.
     #
-    attr_reader :connection_options
-    
+    attr_reader :connection_options, :options
+
     @@traversal_id = :__picky_id
-    
+
     def initialize select_statement, options = { file: 'app/db.yml' }
       @select_statement = select_statement
       @database         = create_database_adapter
       @options          = options
     end
-    
+
+    def to_s
+      parameters = [select_statement.inspect]
+      parameters << options unless options.empty?
+      %Q{#{self.class.name}(#{parameters.join(', ')})}
+    end
+
     # Creates a database adapter for use with this source.
     def create_database_adapter # :nodoc:
       # TODO Do not use ActiveRecord directly.
       #
       # TODO Use set_table_name etc.
       #
       adapter_class = Class.new ActiveRecord::Base
       adapter_class.abstract_class = true
       adapter_class
     end
-    
+
     # Configure the backend.
     #
     # Options:
     #  Either
     #  * file => 'some/filename.yml' # With an active record configuration.
@@ -61,78 +67,78 @@
       else
         options
       end
       self
     end
-    
+
     # Connect the backend.
     #
     # Will raise unless connection options have been given.
     #
     def connect_backend
       configure @options
       raise "Database backend not configured" unless connection_options
       database.establish_connection connection_options
     end
-    
+
     # Take a snapshot of the data.
     #
     # Uses CREATE TABLE AS with the given SELECT statement to create a snapshot of the data.
     #
     def take_snapshot index
       connect_backend
-      
+
       origin = snapshot_table_name index
       on_database = database.connection
-      
+
       # Drop the table if it exists.
       #
       on_database.drop_table origin if on_database.table_exists?(origin)
-      
+
       # The adapters currently do not support this.
       #
       on_database.execute "CREATE TABLE #{origin} AS #{select_statement}"
-      
+
       # Add a column that Picky uses to traverse the table's entries.
       #
       on_database.add_column origin, @@traversal_id, :primary_key, :null => :false
-      
+
       # Execute any special queries this index needs executed.
       #
       on_database.execute index.after_indexing if index.after_indexing
     end
-    
+
     # Counts all the entries that are used for the index.
     #
     def count index
       connect_backend
-      
+
       database.connection.select_value("SELECT COUNT(#{@@traversal_id}) FROM #{snapshot_table_name(index)}").to_i
     end
-    
+
     # The name of the snapshot table created by Picky.
     #
     def snapshot_table_name index
       "picky_#{index.name}_index"
     end
-    
+
     # Harvests the data to index in chunks.
     #
     def harvest index, category, &block
       connect_backend
-      
+
       (0..count(index)).step(chunksize) do |offset|
         get_data index, category, offset, &block
       end
     end
-    
+
     # Gets the data from the backend.
     #
     def get_data index, category, offset, &block # :nodoc:
-      
+
       select_statement = harvest_statement_with_offset index, category, offset
-      
+
       # TODO Rewrite ASAP.
       #
       if database.connection.adapter_name == "PostgreSQL"
         id_key   = 'id'
         text_key = category.from.to_s
@@ -144,31 +150,31 @@
         database.connection.execute(select_statement).each do |id, text|
           yield id, text if text
         end
       end
     end
-    
+
     # Builds a harvest statement for getting data to index.
     #
     def harvest_statement_with_offset index, category, offset
       statement = harvest_statement index, category
-      
+
       statement += statement.include?('WHERE') ? ' AND' : ' WHERE'
-      
+
       "#{statement} st.#{@@traversal_id} > #{offset} LIMIT #{chunksize}"
     end
-    
+
     # The harvest statement used to pull data from the snapshot table.
     #
     def harvest_statement index, category
       "SELECT id, #{category.from} FROM #{snapshot_table_name(index)} st"
     end
-    
+
     # The amount of records that are loaded each chunk.
     #
     def chunksize
       25_000
     end
-    
+
   end
-  
+
 end
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