diff options
Diffstat (limited to 'lib/sqlalchemy/engine/result.py')
| -rw-r--r-- | lib/sqlalchemy/engine/result.py | 204 |
1 files changed, 130 insertions, 74 deletions
diff --git a/lib/sqlalchemy/engine/result.py b/lib/sqlalchemy/engine/result.py index 3995942ef..6eca54a34 100644 --- a/lib/sqlalchemy/engine/result.py +++ b/lib/sqlalchemy/engine/result.py @@ -187,86 +187,142 @@ class ResultMetaData(object): context.""" def __init__(self, parent, metadata): - self._processors = processors = [] - - # We do not strictly need to store the processor in the key mapping, - # though it is faster in the Python version (probably because of the - # saved attribute lookup self._processors) - self._keymap = keymap = {} - self.keys = [] context = parent.context dialect = context.dialect typemap = dialect.dbapi_type_map translate_colname = context._translate_colname - self.case_sensitive = dialect.case_sensitive - - # high precedence key values. - primary_keymap = {} - - for i, rec in enumerate(metadata): - colname = rec[0] - coltype = rec[1] - - if dialect.description_encoding: - colname = dialect._description_decoder(colname) + self.case_sensitive = case_sensitive = dialect.case_sensitive + if context._result_columns: + num_ctx_cols = len(context._result_columns) + else: + num_ctx_cols = None + + if num_ctx_cols and \ + context.compiled._ordered_columns and \ + num_ctx_cols == len(metadata): + # case 1 - SQL expression statement, number of columns + # in result matches number of cols in compiled. This is the + # vast majority case for SQL expression constructs. In this + # case we don't bother trying to parse or match up to + # the colnames in the result description. + raw = [ + ( + idx, + key, + name.lower() if not case_sensitive else name, + context.get_result_processor( + type_, key, metadata[idx][1] + ), + obj, + None + ) for idx, (key, name, obj, type_) + in enumerate(context._result_columns) + ] + self.keys = [ + elem[1] for elem in context._result_columns + ] + else: + # case 2 - raw string, or number of columns in result does + # not match number of cols in compiled. The raw string case + # is very common. The latter can happen + # when text() is used with only a partial typemap, or + # in the extremely unlikely cases where the compiled construct + # has a single element with multiple col expressions in it + # (e.g. has commas embedded) or there's some kind of statement + # that is adding extra columns. + # In all these cases we fall back to the "named" approach + # that SQLAlchemy has used up through 0.9. + + raw = [] + self.keys = [] + untranslated = None + for idx, rec in enumerate(metadata): + colname = rec[0] + coltype = rec[1] + + if dialect.description_encoding: + colname = dialect._description_decoder(colname) + + if translate_colname: + colname, untranslated = translate_colname(colname) + + if dialect.requires_name_normalize: + colname = dialect.normalize_name(colname) + + self.keys.append(colname) + if not case_sensitive: + colname = colname.lower() + + if num_ctx_cols: + try: + ctx_rec = context.result_map[colname] + except KeyError: + mapped_type = typemap.get(coltype, sqltypes.NULLTYPE) + obj = None + else: + obj = ctx_rec[1] + mapped_type = ctx_rec[2] + else: + mapped_type = typemap.get(coltype, sqltypes.NULLTYPE) + obj = None + processor = context.get_result_processor( + mapped_type, colname, coltype) + + raw.append( + (idx, colname, colname, processor, obj, untranslated) + ) + + # keymap indexes by integer index... + self._keymap = dict([ + (elem[0], (elem[3], elem[4], elem[0])) + for elem in raw + ]) + + # processors in key order for certain per-row + # views like __iter__ and slices + self._processors = [elem[3] for elem in raw] + + if num_ctx_cols: + # keymap by primary string... + by_key = dict([ + (elem[2], (elem[3], elem[4], elem[0])) + for elem in raw + ]) + + # if by-primary-string dictionary smaller (or bigger?!) than + # number of columns, assume we have dupes, rewrite + # dupe records with "None" for index which results in + # ambiguous column exception when accessed. + if len(by_key) != num_ctx_cols: + seen = set() + for idx in range(num_ctx_cols): + key = raw[idx][1] + if key in seen: + by_key[key] = (None, by_key[key][1], None) + seen.add(key) + + # update keymap with secondary "object"-based keys + self._keymap.update([ + (obj_elem, by_key[elem[2]]) + for elem in raw if elem[4] + for obj_elem in elem[4] + ]) + + # update keymap with primary string names taking + # precedence + self._keymap.update(by_key) + else: + self._keymap.update([ + (elem[2], (elem[3], elem[4], elem[0])) + for elem in raw + ]) + # update keymap with "translated" names (sqlite-only thing) if translate_colname: - colname, untranslated = translate_colname(colname) - - if dialect.requires_name_normalize: - colname = dialect.normalize_name(colname) - - if context.result_map: - try: - name, obj, type_ = context.result_map[ - colname if self.case_sensitive else colname.lower()] - except KeyError: - name, obj, type_ = \ - colname, None, typemap.get(coltype, sqltypes.NULLTYPE) - else: - name, obj, type_ = \ - colname, None, typemap.get(coltype, sqltypes.NULLTYPE) - - processor = context.get_result_processor(type_, colname, coltype) - - processors.append(processor) - rec = (processor, obj, i) - - # indexes as keys. This is only needed for the Python version of - # RowProxy (the C version uses a faster path for integer indexes). - primary_keymap[i] = rec - - # populate primary keymap, looking for conflicts. - if primary_keymap.setdefault( - name if self.case_sensitive - else name.lower(), - rec) is not rec: - # place a record that doesn't have the "index" - this - # is interpreted later as an AmbiguousColumnError, - # but only when actually accessed. Columns - # colliding by name is not a problem if those names - # aren't used; integer access is always - # unambiguous. - primary_keymap[name - if self.case_sensitive - else name.lower()] = rec = (None, obj, None) - - self.keys.append(colname) - if obj: - for o in obj: - keymap[o] = rec - # technically we should be doing this but we - # are saving on callcounts by not doing so. - # if keymap.setdefault(o, rec) is not rec: - # keymap[o] = (None, obj, None) - - if translate_colname and \ - untranslated: - keymap[untranslated] = rec - - # overwrite keymap values with those of the - # high precedence keymap. - keymap.update(primary_keymap) + self._keymap.update([ + (elem[5], self._keymap[elem[2]]) + for elem in raw if elem[5] + ]) @util.pending_deprecation("0.8", "sqlite dialect uses " "_translate_colname() now") |