/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/transientdb.py
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revision 849 by bh, Wed May 7 11:55:31 2003 UTC revision 1328 by bh, Tue Jul 1 12:01:58 2003 UTC
# Line 22  import os Line 22  import os
22  import weakref  import weakref
23  from sqlite import connect  from sqlite import connect
24    
25    from base import TitledObject
26    
27  import table  import table
28    
29  sql_type_map = {  sql_type_map = {
# Line 240  class TransientTableBase(table.OldTableI Line 242  class TransientTableBase(table.OldTableI
242              result.append(row[0])              result.append(row[0])
243          return result          return result
244    
245        def Width(self, col):
246            """Return the maximum width of values in the column
247    
248            The return value is the the maximum length of string representation
249            of the values in the column (represented by index or name)."""
250            max = 0
251            
252            type  = self.column_map[col].type
253            iname = self.column_map[col].internal_name
254            cursor = self.db.cursor()
255            cursor.execute("SELECT %s FROM %s;" % (iname, self.tablename))
256            values = [ i[0] for i in cursor.fetchall()]
257            if not values:
258                return None
259    
260            if type == sql_type_map[table.FIELDTYPE_DOUBLE]:
261                format = "%.12f"
262            elif type == sql_type_map[table.FIELDTYPE_INT]:
263                format = "%d"
264            else:
265                format = "%s"
266            for value in values:
267                if value is None: continue
268                l = len(format % value)
269                if l > max:
270                    max = l
271    
272            return max
273    
274      def SimpleQuery(self, left, comparison, right):      def SimpleQuery(self, left, comparison, right):
275          """Return the indices of all rows that matching a condition.          """Return the indices of all rows that matching a condition.
276    
# Line 280  class TransientTableBase(table.OldTableI Line 311  class TransientTableBase(table.OldTableI
311              result.append(row[0])              result.append(row[0])
312          return result          return result
313    
314        def Dependencies(self):
315            """Placeholder for a method in a derived class.
316    
317            Return a sequence with the tables and other data objects that
318            self depends on.
319            """
320            raise NotImplementedError
321    
322    
323  class TransientTable(TransientTableBase):  class TransientTable(TitledObject, TransientTableBase):
324    
325      """A Table in a transient DB that starts as the copy of a Thuban Table."""      """A Table in a transient DB that starts as the copy of a Thuban Table."""
326    
# Line 292  class TransientTable(TransientTableBase) Line 331  class TransientTable(TransientTableBase)
331          interface.          interface.
332          """          """
333          TransientTableBase.__init__(self, transient_db)          TransientTableBase.__init__(self, transient_db)
334            TitledObject.__init__(self, table.Title())
335          self.create(table)          self.create(table)
336    
337      def create(self, table):      def create(self, table):
# Line 325  class TransientTable(TransientTableBase) Line 365  class TransientTable(TransientTableBase)
365    
366    
367    
368  class TransientJoinedTable(TransientTableBase):  class TransientJoinedTable(TitledObject, TransientTableBase):
369    
370      """A Table in the transient DB that contains a join of two tables"""      """A Table in the transient DB that contains a join of two tables"""
371    
372      def __init__(self, transient_db, left_table, left_field,      def __init__(self, transient_db, left_table, left_field,
373                   right_table, right_field = None):                   right_table, right_field = None, outer_join = False):
374          """Create a new table in the transient DB as a join of two tables.          """Create a new table in the transient DB as a join of two tables.
375    
376          Both input tables, left_table and right_table must have a          Both input tables, left_table and right_table must have a
377          transient_table method that returns a table object for a table          transient_table method that returns a table object for a table
378          in the trnsient database. The join is performed on the condition          in the transient database. The join is performed on the condition
379          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
380          equal to the value of the right_field in the right_table.          equal to the value of the right_field in the right_table.
381    
# Line 347  class TransientJoinedTable(TransientTabl Line 387  class TransientJoinedTable(TransientTabl
387          names of the input tables without having to create prefixes.          names of the input tables without having to create prefixes.
388          """          """
389          TransientTableBase.__init__(self, transient_db)          TransientTableBase.__init__(self, transient_db)
390            self.dependencies = (left_table, right_table)
391          self.left_table = left_table.transient_table()          self.left_table = left_table.transient_table()
392          self.left_field = left_field          self.left_field = left_field
393          self.right_table = right_table.transient_table()          self.right_table = right_table.transient_table()
# Line 354  class TransientJoinedTable(TransientTabl Line 395  class TransientJoinedTable(TransientTabl
395              self.right_field = right_field              self.right_field = right_field
396          else:          else:
397              self.right_field = self.left_field              self.right_field = self.left_field
398            self.outer_join = outer_join
399    
400            title = "Join of %(left)s and %(right)s" \
401                    % {"left": self.left_table.Title(),
402                       "right": self.right_table.Title()}
403            TitledObject.__init__(self, title)
404    
405          self.create()          self.create()
406    
407      def create(self):      def create(self):
# Line 362  class TransientJoinedTable(TransientTabl Line 410  class TransientJoinedTable(TransientTabl
410    
411          self.right_table.ensure_index(self.right_field)          self.right_table.ensure_index(self.right_field)
412    
413            # determine the internal column names to join on before
414            # coalescing the column information because if the external
415            # column names are the same they will be mapped to the same
416            # internal name afterwards.
417            internal_left_col = self.left_table.orig_to_internal[self.left_field]
418            internal_right_col =self.right_table.orig_to_internal[self.right_field]
419    
420          # Coalesce the column information          # Coalesce the column information
421          visited = {}          visited = {}
422          columns = []          columns = []
# Line 372  class TransientJoinedTable(TransientTabl Line 427  class TransientJoinedTable(TransientTabl
427                  # better solution.                  # better solution.
428                  continue                  continue
429              columns.append(col)              columns.append(col)
430                visited[col.name] = 1
431          TransientTableBase.create(self, columns)          TransientTableBase.create(self, columns)
432    
433          # Copy the joined data to the table.          # Copy the joined data to the table.
434          internal_names = [col.internal_name for col in self.columns]          internal_names = [col.internal_name for col in self.columns]
435            if self.outer_join:
436                join_operator = 'LEFT OUTER JOIN'
437            else:
438                join_operator = 'JOIN'
439          stmt = ("INSERT INTO %s (id, %s) SELECT %s.id, %s FROM %s"          stmt = ("INSERT INTO %s (id, %s) SELECT %s.id, %s FROM %s"
440                  " JOIN %s ON %s = %s;"                  " %s %s ON %s = %s;"
441                  % (self.tablename,                  % (self.tablename,
442                     ", ".join(internal_names),                     ", ".join(internal_names),
443                     self.left_table.tablename,                     self.left_table.tablename,
444                     ", ".join(internal_names),                     ", ".join(internal_names),
445                     self.left_table.tablename,                     self.left_table.tablename,
446                       join_operator,
447                     self.right_table.tablename,                     self.right_table.tablename,
448                     self.orig_to_internal[self.left_field],                     internal_left_col,
449                     self.orig_to_internal[self.right_field]))                     internal_right_col))
450          self.db.execute(stmt)          self.db.execute(stmt)
451    
452        def Dependencies(self):
453            """Return a tuple with the two tables the join depends on."""
454            return self.dependencies
455    
456  class AutoTransientTable(table.OldTableInterfaceMixin):  
457    class AutoTransientTable(TitledObject, table.OldTableInterfaceMixin):
458    
459      """Table that copies data to a transient table on demand.      """Table that copies data to a transient table on demand.
460    
# Line 398  class AutoTransientTable(table.OldTableI Line 463  class AutoTransientTable(table.OldTableI
463      """      """
464    
465      def __init__(self, transient_db, table):      def __init__(self, transient_db, table):
466            TitledObject.__init__(self, table.Title())
467          self.transient_db = transient_db          self.transient_db = transient_db
468          self.table = table          self.table = table
469          self.t_table = None          self.t_table = None
# Line 465  class AutoTransientTable(table.OldTableI Line 531  class AutoTransientTable(table.OldTableI
531          # Make sure to use the column object of the transient table. The          # Make sure to use the column object of the transient table. The
532          # left argument is always a column object so we can just ask the          # left argument is always a column object so we can just ask the
533          # t_table for the right object.          # t_table for the right object.
534          return self.t_table.SimpleQuery(self.t_table.Column(left.name),          if hasattr(right, "name"):
535                                          comparison, right)              return self.t_table.SimpleQuery(self.t_table.Column(left.name),
536                                                comparison,
537                                                self.t_table.Column(right.name))
538            else:
539                return self.t_table.SimpleQuery(self.t_table.Column(left.name),
540                                                comparison, right)
541    
542        def Dependencies(self):
543            """Return a tuple containing the original table"""
544            return (self.table,)
545    
546        def Width(self, col):
547            return self.table.Width(col)
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