github/datasette
1
0
Fork 0
mirror of https://github.com/simonw/datasette.git synced 2025-12-10 16:51:24 +01:00
Code Issues Projects Releases Packages Wiki Activity

Fixed bug with keyset pagination over compound primary keys

Browse source 
Closes #190
This commit is contained in:
Simon Willison 2018-03-29 22:10:09 -07:00
commit 31f63d1672
No known key found for this signature in database
GPG key ID: 17E2DEA2588B7F52
5 changed files with 88 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

14
datasette/app.py
View file

@ -20,6 +20,7 @@ from .utils import (
Filters,
compound_pks_from_path,
CustomJSONEncoder,
compound_keys_after_sql,
detect_fts_sql,
escape_css_string,
escape_sqlite_table_name,
@ -592,15 +593,10 @@ class TableView(RowTableShared):
else:
pk_values = compound_pks_from_path(next)
if len(pk_values) == len(pks):
param_counter = len(params)
for pk, value in zip(pks, pk_values):
where_clauses.append(
'"{}" > :p{}'.format(
pk, param_counter,
)
)
params['p{}'.format(param_counter)] = value
param_counter += 1
where_clauses.append(compound_keys_after_sql(pks))
param_len = len(params)
for i, pk_value in enumerate(pk_values):
params['p{}'.format(param_len + i)] = pk_value
where_clause = ''
if where_clauses:

28
datasette/utils.py
View file

@ -29,6 +29,34 @@ def path_from_row_pks(row, pks, use_rowid):
return ','.join(bits)
def compound_keys_after_sql(pks):
# Implementation of keyset pagination
# See https://github.com/simonw/datasette/issues/190
# For pk1/pk2/pk3 returns:
#
# ([pk1] > :p0)
# or
# ([pk1] = :p0 and [pk2] > :p1)
# or
# ([pk1] = :p0 and [pk2] = :p1 and [pk3] > :p2)
or_clauses = []
pks_left = pks[:]
while pks_left:
and_clauses = []
last = pks_left[-1]
rest = pks_left[:-1]
and_clauses = ['[{}] = :p{}'.format(
pk, i
) for i, pk in enumerate(rest)]
and_clauses.append('[{}] > :p{}'.format(
last, len(rest)
))
or_clauses.append('({})'.format(' and '.join(and_clauses)))
pks_left.pop()
or_clauses.reverse()
return '\n or\n'.join(or_clauses)
class CustomJSONEncoder(json.JSONEncoder):
def default(self, obj):
if isinstance(obj, sqlite3.Row):