args = sys.argv[2:]
# Find the command as a function in this file
- func = globals().get(command, None)
- if func and callable(func) and command != 'main':
+ func = globals().get("command_%s" % command, None)
+ if func:
func(*args)
else:
- help()
+ command_help()
-def csvimport(engine_uri, directory='.'):
+def command_csvimport(engine_uri, directory='.'):
import csv
from sqlalchemy.orm.attributes import instrumentation_registry
- # Use autocommit in case rows fail due to foreign key incest
- session = connect(engine_uri, autocommit=True, autoflush=False)
+ session = connect(engine_uri)
metadata.create_all()
reader = csv.reader(csvfile, lineterminator='\n')
column_names = [unicode(column) for column in reader.next()]
- # Self-referential tables may contain rows with foreign keys of
- # other rows in the same table that do not yet exist. We'll keep
- # a running list of these and try inserting them again after the
- # rest are done
- failed_rows = []
+ # Self-referential tables may contain rows with foreign keys of other
+ # rows in the same table that do not yet exist. Pull these out and add
+ # them to the session last
+ # ASSUMPTION: Self-referential tables have a single PK called "id"
+ deferred_rows = [] # ( row referring to id, [foreign ids we need] )
+ seen_ids = {} # primary key we've seen => 1
+
+ # Fetch foreign key columns that point at this table, if any
+ self_ref_columns = []
+ for column in table_obj.c:
+ if any(_.references(table_obj) for _ in column.foreign_keys):
+ self_ref_columns.append(column)
for csvs in reader:
row = table_class()
setattr(row, column_name, value)
- try:
- session.add(row)
- session.flush()
- except IntegrityError as e:
- failed_rows.append(row)
-
- # Loop over the failed rows and keep trying to insert them. If a loop
- # doesn't manage to insert any rows, bail.
- do_another_loop = True
- while failed_rows and do_another_loop:
- do_another_loop = False
-
- for i, row in enumerate(failed_rows):
- try:
- session.add(row)
- session.flush()
-
- # Success!
- del failed_rows[i]
- do_another_loop = True
- except IntegrityError as e:
- pass
-
- if failed_rows:
- print len(failed_rows), "rows failed"
- else:
- print 'loaded'
-
-def csvexport(engine_uri, directory='.'):
+ # May need to stash this row and add it later if it refers to a
+ # later row in this table
+ if self_ref_columns:
+ foreign_ids = [getattr(row, _.name) for _ in self_ref_columns]
+ foreign_ids = [_ for _ in foreign_ids if _] # remove NULL ids
+
+ if not foreign_ids:
+ # NULL key. Remember this row and add as usual.
+ seen_ids[row.id] = 1
+
+ elif all(_ in seen_ids for _ in foreign_ids):
+ # Non-NULL key we've already seen. Remember it and commit
+ # so we know the old row exists when we add the new one
+ session.commit()
+ seen_ids[row.id] = 1
+
+ else:
+ # Non-NULL future id. Save this and insert it later!
+ deferred_rows.append((row, foreign_ids))
+ continue
+
+ session.add(row)
+
+ session.commit()
+
+ # Attempt to add any spare rows we've collected
+ for row, foreign_ids in deferred_rows:
+ if not all(_ in seen_ids for _ in foreign_ids):
+ # Could happen if row A refers to B which refers to C.
+ # This is ridiculous and doesn't happen in my data so far
+ raise ValueError("Too many levels of self-reference! "
+ "Row was: " + str(row.__dict__))
+
+ session.add(row)
+ seen_ids[row.id] = 1
+ session.commit()
+
+ print 'loaded'
+
+def command_csvexport(engine_uri, directory='.'):
import csv
session = connect(engine_uri)
columns = [col.name for col in table.columns]
writer.writerow(columns)
- for row in session.query(table).all():
+ primary_key = table.primary_key
+ for row in session.query(table).order_by(*primary_key).all():
csvs = []
for col in columns:
# Convert Pythony values to something more universal
writer.writerow(csvs)
-def lookup(engine_uri, name):
+def command_lookup(engine_uri, name):
# XXX don't require uri! somehow
session = connect(engine_uri)
print object.__tablename__, object.name
-def help():
+def command_help():
print u"""pokedex -- a command-line Pokédex interface
help Displays this message.
csvexport {uri} [dir] Export data from the database given by the URI
to a set of CSVs.
Directory defaults to cwd.
-"""
+""".encode(sys.getdefaultencoding(), 'replace')
sys.exit(0)
projects / zzz-pokedex.git / blobdiff