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Started playing with m2m options

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This query is really slow. I think this pattern would be faster:

	select ads.id, ads.text, ads.url
	from ads
	  inner join ad_targets ad_targets_1 on ad_targets_1.ad_id = ads.id
	  inner join ad_targets ad_targets_2 on ad_targets_2.ad_id = ads.id
	  where ad_targets_1.target_id = "cd0d0"
	  and ad_targets_2.target_id = "26eb3"
	order by ads.id
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Simon Willison 2018-07-30 08:16:56 -07:00
commit 0cf91e3f88
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1 changed files with 25 additions and 1 deletions
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26
datasette/views/table.py
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@ -269,7 +269,7 @@ class TableView(RowTableShared):
special_args_lists = {}
other_args = {}
for key, value in args.items():
if key.startswith("_") and "__" not in key:
if (key.startswith("_") and "__" not in key) or key.startswith("_m2m_"):
special_args[key] = value[0]
special_args_lists[key] = value
else:
@ -304,6 +304,30 @@ class TableView(RowTableShared):
filters = Filters(sorted(other_args.items()), units, ureg)
where_clauses, params = filters.build_where_clauses()
# Hacky thing for ?_m2m_ad_targets__target_id=9a8c6
for m2m_key in special_args:
if m2m_key.startswith("_m2m_"):
rest = m2m_key.split("_m2m_", 1)[1]
m2m_table, other_column = rest.split("__", 1)
m2m_table_info = self.ds.inspect()[name]["tables"][m2m_table]
outgoing_fks = m2m_table_info["foreign_keys"]["outgoing"]
fk_to_us = [fk for fk in outgoing_fks if fk["other_table"] == table][0]
# fk_to_other = [
# fk for fk in outgoing_fks
# if fk["other_table"] != table
# and fk["other_column"] == other_column
# ][0]
value = special_args[m2m_key]
# Figure out what the columns are in that m2m table
where_clauses.append(
'{our_pk} in (select {our_pk} from {m2m_table} where {other_column} = "{value}")'.format(
m2m_table=escape_sqlite(m2m_table),
our_pk=fk_to_us["other_column"],
other_column=escape_sqlite(other_column),
value=value,
)
)
# _search support:
fts_table = info[name]["tables"].get(table, {}).get("fts_table")
search_args = dict(