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 |
|
|
382 |
The joined table contains all columns of the input tables with |
The joined table contains all columns of the input tables, |
383 |
one exception: Any column in the right_table with the same name |
however, the column names of the right table may be changed |
384 |
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 |
385 |
somewhat of an implementation detail, but is done so that the |
currently done by appending a sufficient number of underscores |
386 |
column names of the joined table can be the same as the column |
('_'). |
|
names of the input tables without having to create prefixes. |
|
387 |
""" |
""" |
388 |
TransientTableBase.__init__(self, transient_db) |
TransientTableBase.__init__(self, transient_db) |
389 |
self.dependencies = (left_table, right_table) |
self.dependencies = (left_table, right_table) |
414 |
# column names are the same they will be mapped to the same |
# column names are the same they will be mapped to the same |
415 |
# internal name afterwards. |
# internal name afterwards. |
416 |
internal_left_col = self.left_table.orig_to_internal[self.left_field] |
internal_left_col = self.left_table.orig_to_internal[self.left_field] |
417 |
internal_right_col = self.right_table.orig_to_internal[self.right_field] |
internal_right_col =self.right_table.orig_to_internal[self.right_field] |
418 |
|
|
419 |
# Coalesce the column information |
# Coalesce the column information |
420 |
visited = {} |
visited = {} |
421 |
columns = [] |
columns = [] |
422 |
newcolumns = [] |
newcolumns = [] |
423 |
for table, col in ( |
for table in (self.left_table, self.right_table): |
424 |
[ (self.left_table.tablename, c) for c in self.left_table.columns ] |
for col in table.Columns(): |
425 |
+ [ (self.right_table.tablename, c) for c in self.right_table.columns]): |
colname = col.name |
426 |
if col.name in visited: |
# We can't allow multiple columns with the same |
427 |
if col.name == self.left_field: |
# original name, so append '_' to this one until |
428 |
continue |
# it is unique. |
429 |
else: |
# FIXME: There should be a better solution. |
430 |
# We can't allow multiple columns with the same original |
while colname in visited: |
431 |
# name, so append '_' to this one until it is unique. |
colname = colname + '_' |
432 |
# FIXME: There should be a better solution. |
columns.append((table.tablename, col)) |
433 |
while col.name in visited: |
newcol = ColumnReference(colname, col.type, |
434 |
col.name = col.name + '_' |
"Col%03d" % (len(newcolumns)+1)) |
435 |
columns.append((table, col)) |
newcolumns.append(newcol) |
436 |
newcol = ColumnReference(col.name, col.type, |
visited[colname] = 1 |
|
"Col%03d" % (len(newcolumns)+1)) |
|
|
newcolumns.append(newcol) |
|
|
visited[col.name] = 1 |
|
437 |
TransientTableBase.create(self, newcolumns) |
TransientTableBase.create(self, newcolumns) |
438 |
|
|
439 |
# Copy the joined data to the table. |
# Copy the joined data to the table. |
463 |
"""Return a tuple with the two tables the join depends on.""" |
"""Return a tuple with the two tables the join depends on.""" |
464 |
return self.dependencies |
return self.dependencies |
465 |
|
|
466 |
|
def JoinType(self): |
467 |
|
"""Return the type of the join (either 'INNER' or 'LEFT OUTER')""" |
468 |
|
if self.outer_join: |
469 |
|
return "LEFT OUTER" |
470 |
|
else: |
471 |
|
return "INNER" |
472 |
|
|
473 |
|
|
474 |
class AutoTransientTable(TitledObject, table.OldTableInterfaceMixin): |
class AutoTransientTable(TitledObject, table.OldTableInterfaceMixin): |
475 |
|
|