render.rb in pg_graph-0.5.0

- old
+ new

@@ -14,34 +14,48 @@
     #   none - don't delete any data
     #   touched - delete data for tables in the fox file
     #   recursive - delete data for table in the fox file including recursively depending tables
     #   all - delete data from the whole database
     attr_reader :delete
-      
+
+    # Which data to truncate:
+    #   none - don't delete any data
+    #   touched - delete data for tables in the fox file
+    #   all - delete data from the whole database
+    attr_reader :truncate
+
     # +ids+ is a map from table UID to ID. Records with larger IDs will
     # be emitted as insert statements, records with IDs less or equal to the
     # given ID is emitted as update statements
     #
     # +delete+ control which tables are deleted. It can be :none, :touched,
     # :recursive, :all Only records with an ID greater than the corresponding
     # ID from +ids+ will be deleted
     #
+    # +truncate+ acts as +delete+ that has the major drawback that it doesn't
+    # delete records in dependency order (FIXME This is an error). You can use
+    # the SQL truncate statement instead of delete using this option but note
+    # that +ids+ should be empty for this to work
+    #
     # +files+ is a list of source file names to be included in the psql SQL
     # header as documentation. It can be set explicitly when #to_a or #to_h is
     # called (FIXME: is this used?)
-    def initialize(database, format, ids: {}, delete: :all, files: [])
+    def initialize(database, format, ids: {}, delete: :all, truncate: :none, files: [])
 #     puts "SqlRender#initialize"
 #     puts "  format: #{format.inspect}"
 #     puts "  ids: #{ids.inspect}"
 #     puts "  delete: #{delete.inspect}"
 #     puts "  files: #{files.inspect}"
       constrain database, Database
       constrain ids, { String => Integer }
+      constrain ids.empty? || truncate == :none, true
+      constrain delete == :none || truncate == :none, true
       @database = database
       self.format = format
       (@ids = ids.dup).default = 0
       @delete = delete
+      @truncate = truncate
       @files = files
 
       @tables = database.schemas.map(&:tables).flatten.sort
       @insert_tables = []
       @update_tables = []
@@ -77,10 +91,11 @@
 
     def to_h
       @to_h ||= {
         disable: render_triggers(:disable),
         delete: render_deletes(delete),
+        truncate: render_truncates(truncate),
         update: render_updates,
         insert: render_inserts,
         restart: render_restart_sequences,
         enable: render_triggers(:enable),
         refresh: render_refresh_materialized_views
@@ -88,11 +103,15 @@
     end
 
   protected
     # Returns a single-element array of array of SQL statements
     def to_sql
-      [to_h[:delete] + to_h[:update] + to_h[:insert]]
+      if delete != :none
+        [to_h[:delete] + to_h[:update] + to_h[:insert]]
+      else
+        [to_h[:truncate] + to_h[:update] + to_h[:insert]]
+      end
     end
 
     # Returns an array of non-empty arrays of SQL statements
     def to_exec() to_h.values.reject(&:empty?) end
 
@@ -144,16 +163,30 @@
               (tables.map(&:uid) + tables.map { |table| table.type.depending_tables.map(&:uid) }.flatten).uniq
             when :all; @tables.map(&:uid)
           else
             raise ArgumentError
           end
+
+      # FIXME: Not in dependency order
       table_uids.map { |uid|
         if !@ids.key?(uid)
           "delete from #{uid};"
         else
           "delete from #{uid} where id > #{@ids[uid]};"
         end
       }
+    end
+
+    def render_truncates(kind)
+      table_uids = 
+          case kind
+            when :none; []
+            when :touched; @tables.reject(&:empty?).map(&:uid)
+            when :all; @tables.map(&:uid)
+          else
+            raise ArgumentError
+          end
+      table_uids.map { |uid| "truncate #{uid} cascade;" }
     end
 
     def render_updates
       @update_records.map { |record|
         "update #{record.table.uid} set " \