/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/transientdb.py
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revision 1026 by frank, Mon May 26 11:46:42 2003 UTC revision 1381 by bh, Tue Jul 8 16:37:46 2003 UTC
# Line 245  class TransientTableBase(table.OldTableI Line 245  class TransientTableBase(table.OldTableI
245      def Width(self, col):      def Width(self, col):
246          """Return the maximum width of values in the column          """Return the maximum width of values in the column
247    
248          The return value is the the maximum length of string representation          The return value is the the maximum length of string
249          of the values in the column (represented by index or name)."""          representation of the values in the column (represented by index
250            or name).
251            """
252          max = 0          max = 0
253            
254          type  = self.column_map[col].type          type  = self.column_map[col].type
255          iname = self.column_map[col].internal_name          iname = self.column_map[col].internal_name
256          cursor = self.db.cursor()          cursor = self.db.cursor()
# Line 257  class TransientTableBase(table.OldTableI Line 259  class TransientTableBase(table.OldTableI
259          if not values:          if not values:
260              return None              return None
261    
262          if type == sql_type_map[table.FIELDTYPE_DOUBLE]:          if type == table.FIELDTYPE_DOUBLE:
263              prec = self.Precision(col)              format = "%.12f"
264              format = "%%.%df" % prec          elif type == table.FIELDTYPE_INT:
         elif type == sql_type_map[table.FIELDTYPE_INT]:  
265              format = "%d"              format = "%d"
266          else:          else:
267              format = "%s"              format = "%s"
# Line 272  class TransientTableBase(table.OldTableI Line 273  class TransientTableBase(table.OldTableI
273    
274          return max          return max
275    
     def Precision(self, col):  
         """Return the precision of the column  
   
         The return value is the maximum number of numeric characters after the  
         decimal if column type is double. Else precision zero is returned.  
         The column can be represented by index or name.  
         """  
       
         type  = self.column_map[col].type  
         if type == sql_type_map[table.FIELDTYPE_DOUBLE]:  
             iname = self.column_map[col].internal_name  
             cursor = self.db.cursor()  
             cursor.execute("SELECT %s FROM %s;" % (iname, self.tablename))  
             values = [ i[0] for i in cursor.fetchall()]  
             if not values:  
                 return 0  
               
             max = 0  
             for value in values:  
                 if value is None: continue  
                 l = len(str(value % 1))  
                 if l > max:  
                     max = l  
             if max > 2:  
                 return max - 2  
             else:  
                 return 0  
         else:  
             return 0  
   
276      def SimpleQuery(self, left, comparison, right):      def SimpleQuery(self, left, comparison, right):
277          """Return the indices of all rows that matching a condition.          """Return the indices of all rows that matching a condition.
278    
# Line 410  class TransientJoinedTable(TitledObject, Line 381  class TransientJoinedTable(TitledObject,
381          that the value of the left_field column the the left table is          that the value of the left_field column the the left table is
382          equal to the value of the right_field in the right_table.          equal to the value of the right_field in the right_table.
383    
384          The joined table contains all columns of the input tables with          The joined table contains all columns of the input tables,
385          one exception: Any column in the right_table with the same name          however, the column names of the right table may be changed
386          as one of the columns in the left_table will be omitted. This is          slightly to make them unique in the joined table. This is
387          somewhat of an implementation detail, but is done so that the          currently done by appending a sufficient number of underscores
388          column names of the joined table can be the same as the column          ('_').
         names of the input tables without having to create prefixes.  
389          """          """
390          TransientTableBase.__init__(self, transient_db)          TransientTableBase.__init__(self, transient_db)
391          self.dependencies = (left_table, right_table)          self.dependencies = (left_table, right_table)
# Line 441  class TransientJoinedTable(TitledObject, Line 411  class TransientJoinedTable(TitledObject,
411    
412          self.right_table.ensure_index(self.right_field)          self.right_table.ensure_index(self.right_field)
413    
414            # determine the internal column names to join on before
415            # coalescing the column information because if the external
416            # column names are the same they will be mapped to the same
417            # internal name afterwards.
418            internal_left_col = self.left_table.orig_to_internal[self.left_field]
419            internal_right_col =self.right_table.orig_to_internal[self.right_field]
420    
421          # Coalesce the column information          # Coalesce the column information
422          visited = {}          visited = {}
423          columns = []          columns = []
424          for col in self.left_table.columns + self.right_table.columns:          newcolumns = []
425              if col.name in visited:          for table in (self.left_table, self.right_table):
426                  # We can't allow multiple columns with the same original              for col in table.Columns():
427                  # name, so omit this one. FIXME: There should be a                  colname = col.name
428                  # better solution.                  # We can't allow multiple columns with the same
429                  continue                  # original name, so append '_' to this one until
430              columns.append(col)                  # it is unique.
431          TransientTableBase.create(self, columns)                  # FIXME: There should be a better solution.
432                    while colname in visited:
433                        colname = colname + '_'
434                    columns.append((table.tablename, col))
435                    newcol = ColumnReference(colname, col.type,
436                                                "Col%03d" % (len(newcolumns)+1))
437                    newcolumns.append(newcol)
438                    visited[colname] = 1
439            TransientTableBase.create(self, newcolumns)
440    
441          # Copy the joined data to the table.          # Copy the joined data to the table.
442          internal_names = [col.internal_name for col in self.columns]          newinternal_names = [col.internal_name for col in self.columns]
443            internal_references = ["%s.%s" % (table, col.internal_name)
444                                                        for table, col in columns]
445          if self.outer_join:          if self.outer_join:
446              join_operator = 'LEFT OUTER JOIN'              join_operator = 'LEFT OUTER JOIN'
447          else:          else:
448              join_operator = 'JOIN'              join_operator = 'JOIN'
449          stmt = ("INSERT INTO %s (id, %s) SELECT %s.id, %s FROM %s"          stmt = ("INSERT INTO %s (id, %s) SELECT %s.id, %s FROM %s"
450                  " %s %s ON %s = %s;"                  " %s %s ON %s.%s = %s.%s;"
451                  % (self.tablename,                  % (self.tablename,
452                     ", ".join(internal_names),                     ", ".join(newinternal_names),
453                     self.left_table.tablename,                     self.left_table.tablename,
454                     ", ".join(internal_names),                     ", ".join(internal_references),
455                     self.left_table.tablename,                     self.left_table.tablename,
456                     join_operator,                     join_operator,
457                     self.right_table.tablename,                     self.right_table.tablename,
458                     self.orig_to_internal[self.left_field],                     self.left_table.tablename,
459                     self.orig_to_internal[self.right_field]))                     internal_left_col,
460                       self.right_table.tablename,
461                       internal_right_col))
462          self.db.execute(stmt)          self.db.execute(stmt)
463    
464      def Dependencies(self):      def Dependencies(self):
465          """Return a tuple with the two tables the join depends on."""          """Return a tuple with the two tables the join depends on."""
466          return self.dependencies          return self.dependencies
467    
468        def JoinType(self):
469            """Return the type of the join (either 'INNER' or 'LEFT OUTER')"""
470            if self.outer_join:
471                return "LEFT OUTER"
472            else:
473                return "INNER"
474    
475    
476  class AutoTransientTable(TitledObject, table.OldTableInterfaceMixin):  class AutoTransientTable(TitledObject, table.OldTableInterfaceMixin):
477    
# Line 566  class AutoTransientTable(TitledObject, t Line 562  class AutoTransientTable(TitledObject, t
562          """Return a tuple containing the original table"""          """Return a tuple containing the original table"""
563          return (self.table,)          return (self.table,)
564    
565        def Width(self, col):
566            return self.table.Width(col)
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