Revision 2353
Added by Aaron Marcuse-Kubitza over 12 years ago
| lib/sql_gen.py | ||
|---|---|---|
| 174 | 174 |
|
| 175 | 175 |
join_same = object() # tells Join the left and right columns have the same name |
| 176 | 176 |
|
| 177 |
# Tells Join the left and right columns have the same name and are never NULL |
|
| 178 |
join_same_not_null = object() |
|
| 179 |
|
|
| 177 | 180 |
filter_out = object() # tells Join to filter out rows that match the join |
| 178 | 181 |
|
| 179 | 182 |
class Join(Code): |
| ... | ... | |
| 181 | 184 |
''' |
| 182 | 185 |
@param mapping dict(right_table_col=left_table_col, ...) |
| 183 | 186 |
* if left_table_col is join_same: left_table_col = right_table_col |
| 187 |
* Note that right_table_col must be a string |
|
| 188 |
* if left_table_col is join_same_not_null: |
|
| 189 |
left_table_col = right_table_col and both have NOT NULL constraint |
|
| 190 |
* Note that right_table_col must be a string |
|
| 184 | 191 |
@param type_ None (for plain join)|str (e.g. 'LEFT')|filter_out |
| 185 | 192 |
* filter_out: equivalent to 'LEFT' with the query filtered by |
| 186 | 193 |
`table_pkey IS NULL` (indicating no match) |
| ... | ... | |
| 193 | 200 |
self.type_ = type_ |
| 194 | 201 |
|
| 195 | 202 |
def to_str(self, db, left_table): |
| 203 |
# Switch order (left_table is on the right in the comparison) |
|
| 204 |
right_table = left_table |
|
| 205 |
left_table = self.table # note left_table is reassigned |
|
| 206 |
|
|
| 196 | 207 |
def join(entry): |
| 197 | 208 |
'''Parses non-USING joins''' |
| 198 | 209 |
right_table_col, left_table_col = entry |
| 199 |
# Note that right_table_col is on the left in the comparison |
|
| 200 | 210 |
|
| 211 |
# Switch order (right_table_col is on the left in the comparison) |
|
| 212 |
left = right_table_col |
|
| 213 |
right = left_table_col |
|
| 214 |
|
|
| 201 | 215 |
# Parse special values |
| 202 |
if left_table_col is join_same: left_table_col = right_table_col |
|
| 216 |
if right is join_same: right = left |
|
| 217 |
elif right is join_same_not_null: |
|
| 218 |
right = CompareCond(as_Col(left, right_table), '~=') |
|
| 203 | 219 |
|
| 204 |
cond = as_ValueCond(left_table_col, left_table)
|
|
| 205 |
return cond.to_str(db, as_Col(right_table_col, self.table))
|
|
| 220 |
right = as_ValueCond(right, right_table)
|
|
| 221 |
return right.to_str(db, as_Col(left, left_table))
|
|
| 206 | 222 |
|
| 207 | 223 |
# Create join condition |
| 208 | 224 |
type_ = self.type_ |
| ... | ... | |
| 218 | 234 |
if type_ is filter_out: type_ = 'LEFT' |
| 219 | 235 |
str_ = '' |
| 220 | 236 |
if type_ != None: str_ += type_+' ' |
| 221 |
str_ += 'JOIN '+self.table.to_str(db)+' '+join_cond
|
|
| 237 |
str_ += 'JOIN '+left_table.to_str(db)+' '+join_cond
|
|
| 222 | 238 |
return str_ |
| 223 | 239 |
|
| 224 | 240 |
def __str__(self): return self.to_str(mockDb, '') |
Also available in: Unified diff
sql_gen.py: Join: Added join_same_not_null. to_str(): Refactored to switch order of left and right tables and cols because left_table is on the right in the comparison, and using the sides of the comparison instead of the sides of the join makes the code clearer.