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我的情況,我需要跨越像in the Django database model查詢谷歌App Engine的實體關係是。我使用ListProperty
S代表一個一對多的關係,就像這樣:GQL查詢,以有效地跨越實體關係
class Foo(db.Model): bars = db.ListProperty(db.Key)
class Bar(db.Model): eggs = db.ListProperty(db.Key)
而且我想執行一個查詢,執行以下操作:
# Foo.filter('bars.eggs =', target_egg)
[foo
for egg in eggs if egg == target_egg
for eggs in bar.eggs
for bar in foo.bars
for foo in Foo.all()]
的理解似乎根本低效。我真的很想執行查詢作爲註釋部分,但它並不像the GQL syntax允許對屬性的屬性查詢:
SELECT * FROM <kind>
[WHERE <condition> [AND <condition> ...]]
[ORDER BY <property> [ASC | DESC] [, <property> [ASC | DESC] ...]]
[LIMIT [<offset>,]<count>]
[OFFSET <offset>]
<condition> := <property> {< | <= | > | >= | = | != } <value>
<condition> := <property> IN <list>
<condition> := ANCESTOR IS <entity or key>