| 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. |
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